--- /dev/null
+/* pam-cgfs
+ *
+ * Copyright © 2016 Canonical, Inc
+ * Author: Serge Hallyn <serge.hallyn@ubuntu.com>
+ * Author: Christian Brauner <christian.brauner@ubuntu.com>
+ *
+ * When a user logs in, this pam module will create cgroups which the user may
+ * administer. It handles both pure cgroupfs v1 and pure cgroupfs v2, as well as
+ * mixed mounts, where some controllers are mounted in a standard cgroupfs v1
+ * hierarchy location (/sys/fs/cgroup/<controller>) and others are in the
+ * cgroupfs v2 hierarchy.
+ * Writeable cgroups are either created for all controllers or, if specified,
+ * for any controllers listed on the command line.
+ * The cgroup created will be "user/$user/0" for the first session,
+ * "user/$user/1" for the second, etc.
+ *
+ * Systems with a systemd init system are treated specially, both with respect
+ * to cgroupfs v1 and cgroupfs v2. For both, cgroupfs v1 and cgroupfs v2, We
+ * check whether systemd already placed us in a cgroup it created:
+ *
+ * user.slice/user-uid.slice/session-n.scope
+ *
+ * by checking whether uid == our uid. If it did, we simply chown the last
+ * part (session-n.scope). If it did not we create a cgroup as outlined above
+ * (user/$user/n) and chown it to our uid.
+ * The same holds for cgroupfs v2 where this assumptions becomes crucial:
+ * We __have to__ be placed in our under the cgroup systemd created for us on
+ * login, otherwise things like starting an xserver or similar will not work.
+ *
+ * All requested cgroups must be mounted under /sys/fs/cgroup/$controller,
+ * no messing around with finding mountpoints.
+ *
+ * See COPYING file for details.
+ */
+
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <linux/unistd.h>
+#include <sys/mount.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+
+#define PAM_SM_SESSION
+#include <security/_pam_macros.h>
+#include <security/pam_modules.h>
+
+#include "utils.h"
+
+#define pam_cgfs_debug_stream(stream, format, ...) \
+ do { \
+ fprintf(stream, "%s: %d: %s: " format, __FILE__, __LINE__, \
+ __func__, __VA_ARGS__); \
+ } while (false)
+
+#define pam_cgfs_error(format, ...) pam_cgfs_debug_stream(stderr, format, __VA_ARGS__)
+
+#ifdef DEBUG
+#define pam_cgfs_debug(format, ...) pam_cgfs_error(format, __VA_ARGS__)
+#else
+#define pam_cgfs_debug(format, ...)
+#endif /* DEBUG */
+
+/* Taken over modified from the kernel sources. */
+#define NBITS 32 /* bits in uint32_t */
+#define DIV_ROUND_UP(n, d) (((n) + (d)-1) / (d))
+#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, NBITS)
+
+static enum cg_mount_mode {
+ CGROUP_UNKNOWN = -1,
+ CGROUP_MIXED = 0,
+ CGROUP_PURE_V1 = 1,
+ CGROUP_PURE_V2 = 2,
+ CGROUP_UNINITIALIZED = 3,
+} cg_mount_mode = CGROUP_UNINITIALIZED;
+
+/* Common helper functions. Most of these have been taken from LXC. */
+static void append_line(char **dest, size_t oldlen, char *new, size_t newlen);
+static int append_null_to_list(void ***list);
+static void batch_realloc(char **mem, size_t oldlen, size_t newlen);
+static inline void clear_bit(unsigned bit, uint32_t *bitarr)
+{
+ bitarr[bit / NBITS] &= ~(1 << (bit % NBITS));
+}
+static char *copy_to_eol(char *s);
+static void free_string_list(char **list);
+static char *get_mountpoint(char *line);
+static bool get_uid_gid(const char *user, uid_t *uid, gid_t *gid);
+static int handle_login(const char *user, uid_t uid, gid_t gid);
+static inline bool is_set(unsigned bit, uint32_t *bitarr)
+{
+ return (bitarr[bit / NBITS] & (1 << (bit % NBITS))) != 0;
+}
+static bool is_lxcfs(const char *line);
+static bool is_cgv1(char *line);
+static bool is_cgv2(char *line);
+static void *must_alloc(size_t sz);
+static void must_add_to_list(char ***clist, char *entry);
+static void must_append_controller(char **klist, char **nlist, char ***clist,
+ char *entry);
+static void must_append_string(char ***list, char *entry);
+static void mysyslog(int err, const char *format, ...) __attribute__((sentinel));
+static char *read_file(char *fnam);
+static int read_from_file(const char *filename, void* buf, size_t count);
+static int recursive_rmdir(char *dirname);
+static inline void set_bit(unsigned bit, uint32_t *bitarr)
+{
+ bitarr[bit / NBITS] |= (1 << (bit % NBITS));
+}
+static bool string_in_list(char **list, const char *entry);
+static char *string_join(const char *sep, const char **parts, bool use_as_prefix);
+static void trim(char *s);
+static bool write_int(char *path, int v);
+static ssize_t write_nointr(int fd, const void* buf, size_t count);
+static int write_to_file(const char *filename, const void *buf, size_t count,
+ bool add_newline);
+
+/* cgroupfs prototypes. */
+static bool cg_belongs_to_uid_gid(const char *path, uid_t uid, gid_t gid);
+static uint32_t *cg_cpumask(char *buf, size_t nbits);
+static bool cg_copy_parent_file(char *path, char *file);
+static char *cg_cpumask_to_cpulist(uint32_t *bitarr, size_t nbits);
+static bool cg_enter(const char *cgroup);
+static void cg_escape(void);
+static bool cg_filter_and_set_cpus(char *path, bool am_initialized);
+static ssize_t cg_get_max_cpus(char *cpulist);
+static int cg_get_version_of_mntpt(const char *path);
+static bool cg_init(uid_t uid, gid_t gid);
+static void cg_mark_to_make_rw(char **list);
+static void cg_prune_empty_cgroups(const char *user);
+static bool cg_systemd_created_user_slice(const char *base_cgroup,
+ const char *init_cgroup,
+ const char *in, uid_t uid);
+static bool cg_systemd_chown_existing_cgroup(const char *mountpoint,
+ const char *base_cgroup, uid_t uid,
+ gid_t gid,
+ bool systemd_user_slice);
+static bool cg_systemd_under_user_slice_1(const char *in, uid_t uid);
+static bool cg_systemd_under_user_slice_2(const char *base_cgroup,
+ const char *init_cgroup, uid_t uid);
+static void cg_systemd_prune_init_scope(char *cg);
+static bool is_lxcfs(const char *line);
+
+/* cgroupfs v1 prototypes. */
+struct cgv1_hierarchy {
+ char **controllers;
+ char *mountpoint;
+ char *base_cgroup;
+ char *fullcgpath;
+ char *init_cgroup;
+ bool create_rw_cgroup;
+ bool systemd_user_slice;
+};
+
+static struct cgv1_hierarchy **cgv1_hierarchies;
+
+static void cgv1_add_controller(char **clist, char *mountpoint,
+ char *base_cgroup, char *init_cgroup);
+static bool cgv1_controller_in_clist(char *cgline, char *c);
+static bool cgv1_controller_lists_intersect(char **l1, char **l2);
+static bool cgv1_controller_list_is_dup(struct cgv1_hierarchy **hlist,
+ char **clist);
+static bool cgv1_create(const char *cgroup, uid_t uid, gid_t gid,
+ bool *existed);
+static bool cgv1_create_one(struct cgv1_hierarchy *h, const char *cgroup,
+ uid_t uid, gid_t gid, bool *existed);
+static bool cgv1_enter(const char *cgroup);
+static void cgv1_escape(void);
+static bool cgv1_get_controllers(char ***klist, char ***nlist);
+static char *cgv1_get_current_cgroup(char *basecginfo, char *controller);
+static char **cgv1_get_proc_mountinfo_controllers(char **klist, char **nlist,
+ char *line);
+static bool cgv1_handle_cpuset_hierarchy(struct cgv1_hierarchy *h,
+ const char *cgroup);
+static bool cgv1_handle_root_cpuset_hierarchy(struct cgv1_hierarchy *h);
+static bool cgv1_init(uid_t uid, gid_t gid);
+static void cgv1_mark_to_make_rw(char **clist);
+static char *cgv1_must_prefix_named(char *entry);
+static bool cgv1_prune_empty_cgroups(const char *user);
+static bool cgv1_remove_one(struct cgv1_hierarchy *h, const char *cgroup);
+static bool is_cgv1(char *line);
+
+/* cgroupfs v2 prototypes. */
+struct cgv2_hierarchy {
+ char **controllers;
+ char *mountpoint;
+ char *base_cgroup;
+ char *fullcgpath;
+ char *init_cgroup;
+ bool create_rw_cgroup;
+ bool systemd_user_slice;
+};
+
+/* Actually this should only be a single hierarchy. But for the sake of
+ * parallelism and because the layout of the cgroupfs v2 is still somewhat
+ * changing, we'll leave it as an array of structs.
+ */
+static struct cgv2_hierarchy **cgv2_hierarchies;
+
+static void cgv2_add_controller(char **clist, char *mountpoint,
+ char *base_cgroup, char *init_cgroup,
+ bool systemd_user_slice);
+static bool cgv2_create(const char *cgroup, uid_t uid, gid_t gid,
+ bool *existed);
+static bool cgv2_enter(const char *cgroup);
+static void cgv2_escape(void);
+static char *cgv2_get_current_cgroup(int pid);
+static bool cgv2_init(uid_t uid, gid_t gid);
+static void cgv2_mark_to_make_rw(char **clist);
+static bool cgv2_prune_empty_cgroups(const char *user);
+static bool cgv2_remove(const char *cgroup);
+static bool is_cgv2(char *line);
+
+/* Create directory and (if necessary) its parents. */
+static bool mkdir_parent(const char *root, char *path)
+{
+ char *b, orig, *e;
+
+ if (strlen(path) < strlen(root))
+ return false;
+
+ if (strlen(path) == strlen(root))
+ return true;
+
+ b = path + strlen(root) + 1;
+ while (true) {
+ while (*b && (*b == '/'))
+ b++;
+ if (!*b)
+ return true;
+
+ e = b + 1;
+ while (*e && *e != '/')
+ e++;
+
+ orig = *e;
+ if (orig)
+ *e = '\0';
+
+ if (file_exists(path))
+ goto next;
+
+ if (mkdir(path, 0755) < 0) {
+ pam_cgfs_debug("Failed to create %s: %s.\n", path, strerror(errno));
+ return false;
+ }
+
+ next:
+ if (!orig)
+ return true;
+
+ *e = orig;
+ b = e + 1;
+ }
+
+ return false;
+}
+
+/* Common helper functions. Most of these have been taken from LXC. */
+static void mysyslog(int err, const char *format, ...)
+{
+ va_list args;
+
+ va_start(args, format);
+ openlog("PAM-CGFS", LOG_CONS | LOG_PID, LOG_AUTH);
+ vsyslog(err, format, args);
+ va_end(args);
+ closelog();
+}
+
+/* realloc() pointer in batch sizes; do not fail. */
+#define BATCH_SIZE 50
+static void batch_realloc(char **mem, size_t oldlen, size_t newlen)
+{
+ int newbatches = (newlen / BATCH_SIZE) + 1;
+ int oldbatches = (oldlen / BATCH_SIZE) + 1;
+
+ if (!*mem || newbatches > oldbatches)
+ *mem = must_realloc(*mem, newbatches * BATCH_SIZE);
+}
+
+/* Append lines as is to pointer; do not fail. */
+static void append_line(char **dest, size_t oldlen, char *new, size_t newlen)
+{
+ size_t full = oldlen + newlen;
+
+ batch_realloc(dest, oldlen, full + 1);
+
+ memcpy(*dest + oldlen, new, newlen + 1);
+}
+
+/* Read in whole file and return allocated pointer. */
+static char *read_file(char *fnam)
+{
+ FILE *f;
+ int linelen;
+ char *line = NULL, *buf = NULL;
+ size_t len = 0, fulllen = 0;
+
+ f = fopen(fnam, "r");
+ if (!f)
+ return NULL;
+
+ while ((linelen = getline(&line, &len, f)) != -1) {
+ append_line(&buf, fulllen, line, linelen);
+ fulllen += linelen;
+ }
+
+ fclose(f);
+ free(line);
+
+ return buf;
+}
+
+/* Given a pointer to a null-terminated array of pointers, realloc to add one
+ * entry, and point the new entry to NULL. Do not fail. Return the index to the
+ * second-to-last entry - that is, the one which is now available for use
+ * (keeping the list null-terminated).
+ */
+static int append_null_to_list(void ***list)
+{
+ int newentry = 0;
+
+ if (*list)
+ for (; (*list)[newentry]; newentry++) {
+ ;
+ }
+
+ *list = must_realloc(*list, (newentry + 2) * sizeof(void **));
+ (*list)[newentry + 1] = NULL;
+
+ return newentry;
+}
+
+/* Append new entry to null-terminated array of pointer; make sure that array of
+ * pointers will still be null-terminated.
+ */
+static void must_append_string(char ***list, char *entry)
+{
+ int newentry;
+ char *copy;
+
+ newentry = append_null_to_list((void ***)list);
+ copy = must_copy_string(entry);
+ (*list)[newentry] = copy;
+}
+
+/* Remove newlines from string. */
+static void trim(char *s)
+{
+ size_t len = strlen(s);
+
+ while ((len > 0) && s[len - 1] == '\n')
+ s[--len] = '\0';
+}
+
+/* Allocate pointer; do not fail. */
+static void *must_alloc(size_t sz)
+{
+ return must_realloc(NULL, sz);
+}
+
+/* Make allocated copy of string. End of string is taken to be '\n'. */
+static char *copy_to_eol(char *s)
+{
+ char *newline, *sret;
+ size_t len;
+
+ newline = strchr(s, '\n');
+ if (!newline)
+ return NULL;
+
+ len = newline - s;
+ sret = must_alloc(len + 1);
+ memcpy(sret, s, len);
+ sret[len] = '\0';
+
+ return sret;
+}
+
+/* Check if given entry under /proc/<pid>/mountinfo is a fuse.lxcfs mount. */
+static bool is_lxcfs(const char *line)
+{
+ char *p = strstr(line, " - ");
+ if (!p)
+ return false;
+
+ return strncmp(p, " - fuse.lxcfs ", 14) == 0;
+}
+
+/* Check if given entry under /proc/<pid>/mountinfo is a cgroupfs v1 mount. */
+static bool is_cgv1(char *line)
+{
+ char *p = strstr(line, " - ");
+ if (!p)
+ return false;
+
+ return strncmp(p, " - cgroup ", 10) == 0;
+}
+
+/* Check if given entry under /proc/<pid>/mountinfo is a cgroupfs v2 mount. */
+static bool is_cgv2(char *line)
+{
+ char *p = strstr(line, " - ");
+ if (!p)
+ return false;
+
+ return strncmp(p, " - cgroup2 ", 11) == 0;
+}
+
+/* Given a null-terminated array of strings, check whether @entry is one of the
+ * strings
+ */
+static bool string_in_list(char **list, const char *entry)
+{
+ char **it;
+
+ for (it = list; it && *it; it++)
+ if (strcmp(*it, entry) == 0)
+ return true;
+
+ return false;
+}
+
+/*
+ * Creates a null-terminated array of strings, made by splitting the entries in
+ * @str on each @sep. Caller is responsible for calling free_string_list.
+ */
+static char **make_string_list(const char *str, const char *sep)
+{
+ char *copy, *tok;
+ char *saveptr = NULL;
+ char **clist = NULL;
+
+ copy = must_copy_string(str);
+
+ for (tok = strtok_r(copy, sep, &saveptr); tok;
+ tok = strtok_r(NULL, sep, &saveptr))
+ must_add_to_list(&clist, tok);
+
+ free(copy);
+
+ return clist;
+}
+
+/* Gets the length of a null-terminated array of strings. */
+static size_t string_list_length(char **list)
+{
+ size_t len = 0;
+ char **it;
+
+ for (it = list; it && *it; it++)
+ len++;
+
+ return len;
+}
+
+/* Free null-terminated array of strings. */
+static void free_string_list(char **list)
+{
+ char **it;
+
+ for (it = list; it && *it; it++)
+ free(*it);
+ free(list);
+}
+
+/* Write single integer to file. */
+static bool write_int(char *path, int v)
+{
+ FILE *f;
+ bool ret = true;
+
+ f = fopen(path, "w");
+ if (!f)
+ return false;
+
+ if (fprintf(f, "%d\n", v) < 0)
+ ret = false;
+
+ if (fclose(f) != 0)
+ ret = false;
+
+ return ret;
+}
+
+/* Recursively remove directory and its parents. */
+static int recursive_rmdir(char *dirname)
+{
+ struct dirent *direntp;
+ DIR *dir;
+ int r = 0;
+
+ dir = opendir(dirname);
+ if (!dir)
+ return -ENOENT;
+
+ while ((direntp = readdir(dir))) {
+ struct stat st;
+ char *pathname;
+
+ if (!direntp)
+ break;
+
+ if (!strcmp(direntp->d_name, ".") ||
+ !strcmp(direntp->d_name, ".."))
+ continue;
+
+ pathname = must_make_path(dirname, direntp->d_name, NULL);
+
+ if (lstat(pathname, &st)) {
+ if (!r)
+ pam_cgfs_debug("Failed to stat %s.\n", pathname);
+ r = -1;
+ goto next;
+ }
+
+ if (!S_ISDIR(st.st_mode))
+ goto next;
+
+ if (recursive_rmdir(pathname) < 0)
+ r = -1;
+next:
+ free(pathname);
+ }
+
+ if (rmdir(dirname) < 0) {
+ if (!r)
+ pam_cgfs_debug("Failed to delete %s: %s.\n", dirname, strerror(errno));
+ r = -1;
+ }
+
+ if (closedir(dir) < 0) {
+ if (!r)
+ pam_cgfs_debug("Failed to delete %s: %s.\n", dirname, strerror(errno));
+ r = -1;
+ }
+
+ return r;
+}
+
+/* Add new entry to null-terminated array of pointers. Make sure array is still
+ * null-terminated.
+ */
+static void must_add_to_list(char ***clist, char *entry)
+{
+ int newentry;
+
+ newentry = append_null_to_list((void ***)clist);
+ (*clist)[newentry] = must_copy_string(entry);
+}
+
+/* Get mountpoint from a /proc/<pid>/mountinfo line. */
+static char *get_mountpoint(char *line)
+{
+ int i;
+ char *p, *sret, *p2;
+ size_t len;
+
+ p = line;
+
+ for (i = 0; i < 4; i++) {
+ p = strchr(p, ' ');
+ if (!p)
+ return NULL;
+ p++;
+ }
+
+ p2 = strchr(p, ' ');
+ if (p2)
+ *p2 = '\0';
+
+ len = strlen(p);
+ sret = must_alloc(len + 1);
+ memcpy(sret, p, len);
+ sret[len] = '\0';
+
+ return sret;
+}
+
+/* Create list of cgroupfs v1 controller found under /proc/self/cgroup. Skips
+ * the 0::/some/path cgroupfs v2 hierarchy listed. Splits controllers into
+ * kernel controllers (@klist) and named controllers (@nlist).
+ */
+static bool cgv1_get_controllers(char ***klist, char ***nlist)
+{
+ FILE *f;
+ char *line = NULL;
+ size_t len = 0;
+
+ f = fopen("/proc/self/cgroup", "r");
+ if (!f)
+ return false;
+
+ while (getline(&line, &len, f) != -1) {
+ char *p, *p2, *tok;
+ char *saveptr = NULL;
+
+ p = strchr(line, ':');
+ if (!p)
+ continue;
+ p++;
+
+ p2 = strchr(p, ':');
+ if (!p2)
+ continue;
+ *p2 = '\0';
+
+ /* Skip the v2 hierarchy. */
+ if ((p2 - p) == 0)
+ continue;
+
+ for (tok = strtok_r(p, ",", &saveptr); tok;
+ tok = strtok_r(NULL, ",", &saveptr)) {
+ if (strncmp(tok, "name=", 5) == 0)
+ must_append_string(nlist, tok);
+ else
+ must_append_string(klist, tok);
+ }
+ }
+
+ free(line);
+ fclose(f);
+
+ return true;
+}
+
+/* Get list of controllers for cgroupfs v2 hierarchy by looking at
+ * cgroup.controllers and/or cgroup.subtree_control of a given (parent) cgroup.
+static bool cgv2_get_controllers(char ***klist)
+{
+ return -ENOSYS;
+}
+*/
+
+/* Get current cgroup from /proc/self/cgroup for the cgroupfs v2 hierarchy. */
+static char *cgv2_get_current_cgroup(int pid)
+{
+ int ret;
+ char *cgroups_v2;
+ char *current_cgroup;
+ char *copy = NULL;
+ /* The largest integer that can fit into long int is 2^64. This is a
+ * 20-digit number. */
+#define __PIDLEN /* /proc */ 5 + /* /pid-to-str */ 21 + /* /cgroup */ 7 + /* \0 */ 1
+ char path[__PIDLEN];
+
+ ret = snprintf(path, __PIDLEN, "/proc/%d/cgroup", pid);
+ if (ret < 0 || ret >= __PIDLEN)
+ return NULL;
+
+ cgroups_v2 = read_file(path);
+ if (!cgroups_v2)
+ return NULL;
+
+ current_cgroup = strstr(cgroups_v2, "0::/");
+ if (!current_cgroup)
+ goto cleanup_on_err;
+
+ current_cgroup = current_cgroup + 3;
+ copy = copy_to_eol(current_cgroup);
+ if (!copy)
+ goto cleanup_on_err;
+
+cleanup_on_err:
+ free(cgroups_v2);
+ if (copy)
+ trim(copy);
+
+ return copy;
+}
+
+/* Given two null-terminated lists of strings, return true if any string is in
+ * both.
+ */
+static bool cgv1_controller_lists_intersect(char **l1, char **l2)
+{
+ char **it;
+
+ if (!l2)
+ return false;
+
+ for (it = l1; it && *it; it++)
+ if (string_in_list(l2, *it))
+ return true;
+
+ return false;
+}
+
+/* For a null-terminated list of controllers @clist, return true if any of those
+ * controllers is already listed the null-terminated list of hierarchies @hlist.
+ * Realistically, if one is present, all must be present.
+ */
+static bool cgv1_controller_list_is_dup(struct cgv1_hierarchy **hlist, char **clist)
+{
+ struct cgv1_hierarchy **it;
+
+ for (it = hlist; it && *it; it++)
+ if ((*it)->controllers)
+ if (cgv1_controller_lists_intersect((*it)->controllers, clist))
+ return true;
+ return false;
+
+}
+
+/* Set boolean to mark controllers under which we are supposed create a
+ * writeable cgroup.
+ */
+static void cgv1_mark_to_make_rw(char **clist)
+{
+ struct cgv1_hierarchy **it;
+
+ for (it = cgv1_hierarchies; it && *it; it++)
+ if ((*it)->controllers)
+ if (cgv1_controller_lists_intersect((*it)->controllers, clist) ||
+ string_in_list(clist, "all"))
+ (*it)->create_rw_cgroup = true;
+}
+
+/* Set boolean to mark whether we are supposed to create a writeable cgroup in
+ * the cgroupfs v2 hierarchy.
+ */
+static void cgv2_mark_to_make_rw(char **clist)
+{
+ if (string_in_list(clist, "unified") || string_in_list(clist, "all"))
+ if (cgv2_hierarchies)
+ (*cgv2_hierarchies)->create_rw_cgroup = true;
+}
+
+/* Wrapper around cgv{1,2}_mark_to_make_rw(). */
+static void cg_mark_to_make_rw(char **clist)
+{
+ cgv1_mark_to_make_rw(clist);
+ cgv2_mark_to_make_rw(clist);
+}
+
+/* Prefix any named controllers with "name=", e.g. "name=systemd". */
+static char *cgv1_must_prefix_named(char *entry)
+{
+ char *s;
+ int ret;
+ size_t len;
+
+ len = strlen(entry);
+ s = must_alloc(len + 6);
+
+ ret = snprintf(s, len + 6, "name=%s", entry);
+ if (ret < 0 || (size_t)ret >= (len + 6))
+ return NULL;
+
+ return s;
+}
+
+/* Append kernel controller in @klist or named controller in @nlist to @clist */
+static void must_append_controller(char **klist, char **nlist, char ***clist, char *entry)
+{
+ int newentry;
+ char *copy;
+
+ if (string_in_list(klist, entry) && string_in_list(nlist, entry))
+ return;
+
+ newentry = append_null_to_list((void ***)clist);
+
+ if (strncmp(entry, "name=", 5) == 0)
+ copy = must_copy_string(entry);
+ else if (string_in_list(klist, entry))
+ copy = must_copy_string(entry);
+ else
+ copy = cgv1_must_prefix_named(entry);
+
+ (*clist)[newentry] = copy;
+}
+
+/* Get the controllers from a mountinfo line. There are other ways we could get
+ * this info. For lxcfs, field 3 is /cgroup/controller-list. For cgroupfs, we
+ * could parse the mount options. But we simply assume that the mountpoint must
+ * be /sys/fs/cgroup/controller-list
+ */
+static char **cgv1_get_proc_mountinfo_controllers(char **klist, char **nlist, char *line)
+{
+ int i;
+ char *p, *p2, *tok;
+ char *saveptr = NULL;
+ char **aret = NULL;
+
+ p = line;
+
+ for (i = 0; i < 4; i++) {
+ p = strchr(p, ' ');
+ if (!p)
+ return NULL;
+ p++;
+ }
+ if (!p)
+ return NULL;
+
+ if (strncmp(p, "/sys/fs/cgroup/", 15) != 0)
+ return NULL;
+
+ p += 15;
+
+ p2 = strchr(p, ' ');
+ if (!p2)
+ return NULL;
+ *p2 = '\0';
+
+ for (tok = strtok_r(p, ",", &saveptr); tok;
+ tok = strtok_r(NULL, ",", &saveptr))
+ must_append_controller(klist, nlist, &aret, tok);
+
+ return aret;
+}
+
+/* Check if a cgroupfs v2 controller is present in the string @cgline. */
+static bool cgv1_controller_in_clist(char *cgline, char *c)
+{
+ size_t len;
+ char *tok, *eol, *tmp;
+ char *saveptr = NULL;
+
+ eol = strchr(cgline, ':');
+ if (!eol)
+ return false;
+
+ len = eol - cgline;
+ tmp = alloca(len + 1);
+ memcpy(tmp, cgline, len);
+ tmp[len] = '\0';
+
+ for (tok = strtok_r(tmp, ",", &saveptr); tok;
+ tok = strtok_r(NULL, ",", &saveptr)) {
+ if (strcmp(tok, c) == 0)
+ return true;
+ }
+ return false;
+}
+
+/* Get current cgroup from the /proc/<pid>/cgroup file passed in via @basecginfo
+ * of a given cgv1 controller passed in via @controller.
+ */
+static char *cgv1_get_current_cgroup(char *basecginfo, char *controller)
+{
+ char *p;
+
+ p = basecginfo;
+
+ while (true) {
+ p = strchr(p, ':');
+ if (!p)
+ return NULL;
+ p++;
+
+ if (cgv1_controller_in_clist(p, controller)) {
+ p = strchr(p, ':');
+ if (!p)
+ return NULL;
+ p++;
+
+ return copy_to_eol(p);
+ }
+
+ p = strchr(p, '\n');
+ if (!p)
+ return NULL;
+ p++;
+ }
+
+ return NULL;
+}
+
+/* Remove /init.scope from string @cg. This will mostly affect systemd-based
+ * systems.
+ */
+#define INIT_SCOPE "/init.scope"
+static void cg_systemd_prune_init_scope(char *cg)
+{
+ char *point;
+
+ if (!cg)
+ return;
+
+ point = cg + strlen(cg) - strlen(INIT_SCOPE);
+ if (point < cg)
+ return;
+
+ if (strcmp(point, INIT_SCOPE) == 0) {
+ if (point == cg)
+ *(point + 1) = '\0';
+ else
+ *point = '\0';
+ }
+}
+
+/* Add new info about a mounted cgroupfs v1 hierarchy. Includes the controllers
+ * mounted into that hierarchy (e.g. cpu,cpuacct), the mountpoint of that
+ * hierarchy (/sys/fs/cgroup/<controller>, the base cgroup of the current
+ * process gathered from /proc/self/cgroup, and the init cgroup of PID1 gathered
+ * from /proc/1/cgroup.
+ */
+static void cgv1_add_controller(char **clist, char *mountpoint, char *base_cgroup, char *init_cgroup)
+{
+ struct cgv1_hierarchy *new;
+ int newentry;
+
+ new = must_alloc(sizeof(*new));
+ new->controllers = clist;
+ new->mountpoint = mountpoint;
+ new->base_cgroup = base_cgroup;
+ new->fullcgpath = NULL;
+ new->create_rw_cgroup = false;
+ new->init_cgroup = init_cgroup;
+ new->systemd_user_slice = false;
+
+ newentry = append_null_to_list((void ***)&cgv1_hierarchies);
+ cgv1_hierarchies[newentry] = new;
+}
+
+/* Add new info about the mounted cgroupfs v2 hierarchy. Can (but doesn't
+ * currently) include the controllers mounted into the hierarchy (e.g. memory,
+ * pids, blkio), the mountpoint of that hierarchy (Should usually be
+ * /sys/fs/cgroup but some init systems seems to think it might be a good idea
+ * to also mount empty cgroupfs v2 hierarchies at /sys/fs/cgroup/systemd.), the
+ * base cgroup of the current process gathered from /proc/self/cgroup, and the
+ * init cgroup of PID1 gathered from /proc/1/cgroup.
+ */
+static void cgv2_add_controller(char **clist, char *mountpoint, char *base_cgroup, char *init_cgroup, bool systemd_user_slice)
+{
+ struct cgv2_hierarchy *new;
+ int newentry;
+
+ new = must_alloc(sizeof(*new));
+ new->controllers = clist;
+ new->mountpoint = mountpoint;
+ new->base_cgroup = base_cgroup;
+ new->fullcgpath = NULL;
+ new->create_rw_cgroup = false;
+ new->init_cgroup = init_cgroup;
+ new->systemd_user_slice = systemd_user_slice;
+
+ newentry = append_null_to_list((void ***)&cgv2_hierarchies);
+ cgv2_hierarchies[newentry] = new;
+}
+
+/* In Ubuntu 14.04, the paths created for us were
+ * '/user/$uid.user/$something.session' This can be merged better with
+ * systemd_created_slice_for_us(), but keeping it separate makes it easier to
+ * reason about the correctness.
+ */
+static bool cg_systemd_under_user_slice_1(const char *in, uid_t uid)
+{
+ char *p;
+ size_t len;
+ int id;
+ char *copy = NULL;
+ bool bret = false;
+
+ copy = must_copy_string(in);
+ if (strlen(copy) < strlen("/user/1.user/1.session"))
+ goto cleanup;
+ p = copy + strlen(copy) - 1;
+
+ /* skip any trailing '/' (shouldn't be any, but be sure) */
+ while (p >= copy && *p == '/')
+ *(p--) = '\0';
+ if (p < copy)
+ goto cleanup;
+
+ /* Get last path element */
+ while (p >= copy && *p != '/')
+ p--;
+ if (p < copy)
+ goto cleanup;
+ /* make sure it is something.session */
+ len = strlen(p + 1);
+ if (len < strlen("1.session") ||
+ strncmp(p + 1 + len - 8, ".session", 8) != 0)
+ goto cleanup;
+
+ /* ok last path piece checks out, now check the second to last */
+ *(p + 1) = '\0';
+ while (p >= copy && *(--p) != '/')
+ ;
+ if (sscanf(p + 1, "%d.user/", &id) != 1)
+ goto cleanup;
+
+ if (id != (int)uid)
+ goto cleanup;
+
+ bret = true;
+
+cleanup:
+ free(copy);
+ return bret;
+}
+
+/* So long as our path relative to init starts with /user.slice/user-$uid.slice,
+ * assume it belongs to $uid and chown it
+ */
+static bool cg_systemd_under_user_slice_2(const char *base_cgroup,
+ const char *init_cgroup, uid_t uid)
+{
+ int ret;
+ char buf[100];
+ size_t curlen, initlen;
+
+ curlen = strlen(base_cgroup);
+ initlen = strlen(init_cgroup);
+ if (curlen <= initlen)
+ return false;
+
+ if (strncmp(base_cgroup, init_cgroup, initlen) != 0)
+ return false;
+
+ ret = snprintf(buf, 100, "/user.slice/user-%d.slice/", (int)uid);
+ if (ret < 0 || ret >= 100)
+ return false;
+
+ if (initlen == 1)
+ initlen = 0; // skip the '/'
+
+ return strncmp(base_cgroup + initlen, buf, strlen(buf)) == 0;
+}
+
+/* The systemd-created path is: user-$uid.slice/session-c$session.scope. If that
+ * is not the end of our systemd path, then we're not part of the PAM call that
+ * created that path.
+ *
+ * The last piece is chowned to $uid, the user- part not.
+ * Note: If the user creates paths that look like what we're looking for to
+ * 'fool' us, either
+ * - they fool us, we create new cgroups, and they get auto-logged-out.
+ * - they fool a root sudo, systemd cgroup is not changed but chowned, and they
+ * lose ownership of their cgroups
+ */
+static bool cg_systemd_created_user_slice(const char *base_cgroup,
+ const char *init_cgroup,
+ const char *in, uid_t uid)
+{
+ char *p;
+ size_t len;
+ int id;
+ char *copy = NULL;
+ bool bret = false;
+
+ copy = must_copy_string(in);
+
+ /* An old version of systemd has already created a cgroup for us. */
+ if (cg_systemd_under_user_slice_1(in, uid))
+ goto succeed;
+
+ /* A new version of systemd has already created a cgroup for us. */
+ if (cg_systemd_under_user_slice_2(base_cgroup, init_cgroup, uid))
+ goto succeed;
+
+ if (strlen(copy) < strlen("/user-0.slice/session-0.scope"))
+ goto cleanup;
+
+ p = copy + strlen(copy) - 1;
+ /* Skip any trailing '/' (shouldn't be any, but be sure). */
+ while (p >= copy && *p == '/')
+ *(p--) = '\0';
+
+ if (p < copy)
+ goto cleanup;
+
+ /* Get last path element */
+ while (p >= copy && *p != '/')
+ p--;
+
+ if (p < copy)
+ goto cleanup;
+
+ /* Make sure it is session-something.scope. */
+ len = strlen(p + 1);
+ if (strncmp(p + 1, "session-", strlen("session-")) != 0 ||
+ strncmp(p + 1 + len - 6, ".scope", 6) != 0)
+ goto cleanup;
+
+ /* Ok last path piece checks out, now check the second to last. */
+ *(p + 1) = '\0';
+ while (p >= copy && *(--p) != '/')
+ ;
+
+ if (sscanf(p + 1, "user-%d.slice/", &id) != 1)
+ goto cleanup;
+
+ if (id != (int)uid)
+ goto cleanup;
+
+succeed:
+ bret = true;
+cleanup:
+ free(copy);
+ return bret;
+}
+
+/* Chown existing cgroup that systemd has already created for us. */
+static bool cg_systemd_chown_existing_cgroup(const char *mountpoint,
+ const char *base_cgroup, uid_t uid,
+ gid_t gid, bool systemd_user_slice)
+{
+ char *path;
+
+ if (!systemd_user_slice)
+ return false;
+
+ path = must_make_path(mountpoint, base_cgroup, NULL);
+
+ /* A cgroup within name=systemd has already been created. So we only
+ * need to chown it.
+ */
+ if (chown(path, uid, gid) < 0)
+ mysyslog(LOG_WARNING, "Failed to chown %s to %d:%d: %s.\n",
+ path, (int)uid, (int)gid, strerror(errno), NULL);
+ pam_cgfs_debug("Chowned %s to %d:%d.\n", path, (int)uid, (int)gid);
+
+ free(path);
+ return true;
+}
+
+/* Detect and store information about cgroupfs v1 hierarchies. */
+static bool cgv1_init(uid_t uid, gid_t gid)
+{
+ FILE *f;
+ struct cgv1_hierarchy **it;
+ char *basecginfo;
+ char *line = NULL;
+ char **klist = NULL, **nlist = NULL;
+ size_t len = 0;
+
+ basecginfo = read_file("/proc/self/cgroup");
+ if (!basecginfo)
+ return false;
+
+ f = fopen("/proc/self/mountinfo", "r");
+ if (!f) {
+ free(basecginfo);
+ return false;
+ }
+
+ cgv1_get_controllers(&klist, &nlist);
+
+ while (getline(&line, &len, f) != -1) {
+ char **controller_list = NULL;
+ char *mountpoint, *base_cgroup;
+
+ if (is_lxcfs(line) || !is_cgv1(line))
+ continue;
+
+ controller_list = cgv1_get_proc_mountinfo_controllers(klist, nlist, line);
+ if (!controller_list)
+ continue;
+
+ if (cgv1_controller_list_is_dup(cgv1_hierarchies,
+ controller_list)) {
+ free(controller_list);
+ continue;
+ }
+
+ mountpoint = get_mountpoint(line);
+ if (!mountpoint) {
+ free_string_list(controller_list);
+ continue;
+ }
+
+ base_cgroup = cgv1_get_current_cgroup(basecginfo, controller_list[0]);
+ if (!base_cgroup) {
+ free_string_list(controller_list);
+ free(mountpoint);
+ continue;
+ }
+ trim(base_cgroup);
+ pam_cgfs_debug("Detected cgroupfs v1 controller \"%s\" with "
+ "mountpoint \"%s\" and cgroup \"%s\".\n",
+ controller_list[0], mountpoint, base_cgroup);
+ cgv1_add_controller(controller_list, mountpoint, base_cgroup,
+ NULL);
+ }
+ free_string_list(klist);
+ free_string_list(nlist);
+ free(basecginfo);
+ fclose(f);
+ free(line);
+
+ /* Retrieve init cgroup path for all controllers. */
+ basecginfo = read_file("/proc/1/cgroup");
+ if (!basecginfo)
+ return false;
+
+ for (it = cgv1_hierarchies; it && *it; it++) {
+ if ((*it)->controllers) {
+ char *init_cgroup, *user_slice;
+ /* We've already stored the controller and received its
+ * current cgroup. If we now fail to retrieve its init
+ * cgroup, we should probably fail.
+ */
+ init_cgroup = cgv1_get_current_cgroup(basecginfo, (*it)->controllers[0]);
+ if (!init_cgroup) {
+ free(basecginfo);
+ return false;
+ }
+ cg_systemd_prune_init_scope(init_cgroup);
+ (*it)->init_cgroup = init_cgroup;
+ pam_cgfs_debug("cgroupfs v1 controller \"%s\" has init "
+ "cgroup \"%s\".\n",
+ (*(*it)->controllers), init_cgroup);
+ /* Check whether systemd has already created a cgroup
+ * for us.
+ */
+ user_slice = must_make_path((*it)->mountpoint, (*it)->base_cgroup, NULL);
+ if (cg_systemd_created_user_slice((*it)->base_cgroup, (*it)->init_cgroup, user_slice, uid))
+ (*it)->systemd_user_slice = true;
+ }
+ }
+ free(basecginfo);
+
+ return true;
+}
+
+/* Check whether @path is a cgroupfs v1 or cgroupfs v2 mount. Returns -1 if
+ * statfs fails. If @path is null /sys/fs/cgroup is checked.
+ */
+static inline int cg_get_version_of_mntpt(const char *path)
+{
+ if (has_fs_type(path, CGROUP_SUPER_MAGIC))
+ return 1;
+
+ if (has_fs_type(path, CGROUP2_SUPER_MAGIC))
+ return 2;
+
+ return 0;
+}
+
+/* Detect and store information about the cgroupfs v2 hierarchy. Currently only
+ * deals with the empty v2 hierachy as we do not retrieve enabled controllers.
+ */
+static bool cgv2_init(uid_t uid, gid_t gid)
+{
+ char *mountpoint;
+ FILE *f = NULL;
+ char *current_cgroup = NULL, *init_cgroup = NULL;
+ char * line = NULL;
+ size_t len = 0;
+ int ret = false;
+
+ current_cgroup = cgv2_get_current_cgroup(getpid());
+ if (!current_cgroup) {
+ /* No v2 hierarchy present. We're done. */
+ ret = true;
+ goto cleanup;
+ }
+
+ init_cgroup = cgv2_get_current_cgroup(1);
+ if (!init_cgroup) {
+ /* If we're here and didn't fail already above, then something's
+ * certainly wrong, so error this time.
+ */
+ goto cleanup;
+ }
+ cg_systemd_prune_init_scope(init_cgroup);
+
+ /* Check if the v2 hierarchy is mounted at its standard location.
+ * If so we can skip the rest of the work here. Although the unified
+ * hierarchy can be mounted multiple times, each of those mountpoints
+ * will expose identical information.
+ */
+ if (cg_get_version_of_mntpt("/sys/fs/cgroup") == 2) {
+ char *user_slice;
+ bool has_user_slice = false;
+
+ mountpoint = must_copy_string("/sys/fs/cgroup");
+ if (!mountpoint)
+ goto cleanup;
+
+ user_slice = must_make_path(mountpoint, current_cgroup, NULL);
+ if (cg_systemd_created_user_slice(current_cgroup, init_cgroup, user_slice, uid))
+ has_user_slice = true;
+ free(user_slice);
+
+ cgv2_add_controller(NULL, mountpoint, current_cgroup, init_cgroup, has_user_slice);
+
+ ret = true;
+ goto cleanup;
+ }
+
+ f = fopen("/proc/self/mountinfo", "r");
+ if (!f)
+ goto cleanup;
+
+ /* we support simple cgroup mounts and lxcfs mounts */
+ while (getline(&line, &len, f) != -1) {
+ char *user_slice;
+ bool has_user_slice = false;
+ if (!is_cgv2(line))
+ continue;
+
+ mountpoint = get_mountpoint(line);
+ if (!mountpoint)
+ continue;
+
+ user_slice = must_make_path(mountpoint, current_cgroup, NULL);
+ if (cg_systemd_created_user_slice(current_cgroup, init_cgroup, user_slice, uid))
+ has_user_slice = true;
+ free(user_slice);
+
+ cgv2_add_controller(NULL, mountpoint, current_cgroup, init_cgroup, has_user_slice);
+ /* Although the unified hierarchy can be mounted multiple times,
+ * each of those mountpoints will expose identical information.
+ * So let the first mountpoint we find, win.
+ */
+ ret = true;
+ break;
+ }
+
+ pam_cgfs_debug("Detected cgroupfs v2 hierarchy at mountpoint \"%s\" with "
+ "current cgroup \"%s\" and init cgroup \"%s\".\n",
+ mountpoint, current_cgroup, init_cgroup);
+
+cleanup:
+ if (f)
+ fclose(f);
+ free(line);
+
+ return ret;
+}
+
+/* Detect and store information about mounted cgroupfs v1 hierarchies and the
+ * cgroupfs v2 hierarchy.
+ * Detect whether we are on a pure cgroupfs v1, cgroupfs v2, or mixed system,
+ * where some controllers are mounted into their standard cgroupfs v1 locations
+ * (/sys/fs/cgroup/<controller>) and others are mounted into the cgroupfs v2
+ * hierarchy (/sys/fs/cgroup).
+ */
+static bool cg_init(uid_t uid, gid_t gid)
+{
+ if (!cgv1_init(uid, gid))
+ return false;
+
+ if (!cgv2_init(uid, gid))
+ return false;
+
+ if (cgv1_hierarchies && cgv2_hierarchies) {
+ cg_mount_mode = CGROUP_MIXED;
+ pam_cgfs_debug("%s\n", "Detected cgroupfs v1 and v2 hierarchies.");
+ } else if (cgv1_hierarchies && !cgv2_hierarchies) {
+ cg_mount_mode = CGROUP_PURE_V1;
+ pam_cgfs_debug("%s\n", "Detected cgroupfs v1 hierarchies.");
+ } else if (cgv2_hierarchies && !cgv1_hierarchies) {
+ cg_mount_mode = CGROUP_PURE_V2;
+ pam_cgfs_debug("%s\n", "Detected cgroupfs v2 hierarchies.");
+ } else {
+ cg_mount_mode = CGROUP_UNKNOWN;
+ mysyslog(LOG_ERR, "Could not detect cgroupfs hierarchy.\n", NULL);
+ }
+
+ if (cg_mount_mode == CGROUP_UNKNOWN)
+ return false;
+
+ return true;
+}
+
+/* Try to move/migrate us into @cgroup in a cgroupfs v1 hierarchy. */
+static bool cgv1_enter(const char *cgroup)
+{
+ struct cgv1_hierarchy **it;
+
+ for (it = cgv1_hierarchies; it && *it; it++) {
+ char **controller;
+ bool entered = false;
+
+ if (!(*it)->controllers || !(*it)->mountpoint ||
+ !(*it)->init_cgroup || !(*it)->create_rw_cgroup)
+ continue;
+
+ for (controller = (*it)->controllers; controller && *controller;
+ controller++) {
+ char *path;
+
+ /* We've already been placed in a user slice, so we
+ * don't need to enter the cgroup again.
+ */
+ if ((*it)->systemd_user_slice) {
+ entered = true;
+ break;
+ }
+
+ path = must_make_path((*it)->mountpoint,
+ (*it)->init_cgroup,
+ cgroup,
+ "/cgroup.procs",
+ NULL);
+ if (!file_exists(path)) {
+ free(path);
+ path = must_make_path((*it)->mountpoint,
+ (*it)->init_cgroup,
+ cgroup,
+ "/tasks",
+ NULL);
+ }
+ pam_cgfs_debug("Attempting to enter cgroupfs v1 hierarchy in \"%s\" cgroup.\n", path);
+ entered = write_int(path, (int)getpid());
+ if (entered) {
+ free(path);
+ break;
+ }
+ pam_cgfs_debug("Failed to enter cgroupfs v1 hierarchy in \"%s\" cgroup.\n", path);
+ free(path);
+ }
+ if (!entered)
+ return false;
+ }
+
+ return true;
+}
+
+/* Try to move/migrate us into @cgroup in the cgroupfs v2 hierarchy. */
+static bool cgv2_enter(const char *cgroup)
+{
+ struct cgv2_hierarchy *v2;
+ char *path;
+ bool entered = false;
+
+ if (!cgv2_hierarchies)
+ return true;
+
+ v2 = *cgv2_hierarchies;
+
+ if (!v2->mountpoint || !v2->base_cgroup)
+ return false;
+
+ if (!v2->create_rw_cgroup || v2->systemd_user_slice)
+ return true;
+
+ path = must_make_path(v2->mountpoint, v2->base_cgroup, cgroup, "/cgroup.procs", NULL);
+ pam_cgfs_debug("Attempting to enter cgroupfs v2 hierarchy in cgroup \"%s\".\n", path);
+ entered = write_int(path, (int)getpid());
+ if (!entered) {
+ pam_cgfs_debug("Failed to enter cgroupfs v2 hierarchy in cgroup \"%s\".\n", path);
+ free(path);
+ return false;
+ }
+
+ free(path);
+
+ return true;
+}
+
+/* Wrapper around cgv{1,2}_enter(). */
+static bool cg_enter(const char *cgroup)
+{
+ if (!cgv1_enter(cgroup)) {
+ mysyslog(LOG_WARNING, "cgroupfs v1: Failed to enter cgroups.\n", NULL);
+ return false;
+ }
+
+ if (!cgv2_enter(cgroup)) {
+ mysyslog(LOG_WARNING, "cgroupfs v2: Failed to enter cgroups.\n", NULL);
+ return false;
+ }
+
+ return true;
+}
+
+/* Escape to root cgroup in all detected cgroupfs v1 hierarchies. */
+static void cgv1_escape(void)
+{
+ struct cgv1_hierarchy **it;
+
+ /* In case systemd hasn't already placed us in a user slice for the
+ * cpuset v1 controller we will reside in the root cgroup. This means
+ * that cgroup.clone_children will not have been initialized for us so
+ * we need to do it.
+ */
+ for (it = cgv1_hierarchies; it && *it; it++)
+ if (!cgv1_handle_root_cpuset_hierarchy(*it))
+ mysyslog(LOG_WARNING, "cgroupfs v1: Failed to initialize cpuset.\n", NULL);
+
+ if (!cgv1_enter("/"))
+ mysyslog(LOG_WARNING, "cgroupfs v1: Failed to escape to init's cgroup.\n", NULL);
+}
+
+/* Escape to root cgroup in the cgroupfs v2 hierarchy. */
+static void cgv2_escape(void)
+{
+ if (!cgv2_enter("/"))
+ mysyslog(LOG_WARNING, "cgroupfs v2: Failed to escape to init's cgroup.\n", NULL);
+}
+
+/* Wrapper around cgv{1,2}_escape(). */
+static void cg_escape(void)
+{
+ cgv1_escape();
+ cgv2_escape();
+}
+
+/* Get uid and gid for @user. */
+static bool get_uid_gid(const char *user, uid_t *uid, gid_t *gid)
+{
+ struct passwd *pwent;
+
+ pwent = getpwnam(user);
+ if (!pwent)
+ return false;
+
+ *uid = pwent->pw_uid;
+ *gid = pwent->pw_gid;
+
+ return true;
+}
+
+/* Check if cgroup belongs to our uid and gid. If so, reuse it. */
+static bool cg_belongs_to_uid_gid(const char *path, uid_t uid, gid_t gid)
+{
+ struct stat statbuf;
+
+ if (stat(path, &statbuf) < 0)
+ return false;
+
+ if (!(statbuf.st_uid == uid) || !(statbuf.st_gid == gid))
+ return false;
+
+ return true;
+}
+
+/* Create cpumask from cpulist aka turn:
+ *
+ * 0,2-3
+ *
+ * into bit array
+ *
+ * 1 0 1 1
+ */
+static uint32_t *cg_cpumask(char *buf, size_t nbits)
+{
+ char *token;
+ char *saveptr = NULL;
+ size_t arrlen = BITS_TO_LONGS(nbits);
+ uint32_t *bitarr = calloc(arrlen, sizeof(uint32_t));
+ if (!bitarr)
+ return NULL;
+
+ for (; (token = strtok_r(buf, ",", &saveptr)); buf = NULL) {
+ errno = 0;
+ unsigned start = strtoul(token, NULL, 0);
+ unsigned end = start;
+
+ char *range = strchr(token, '-');
+ if (range)
+ end = strtoul(range + 1, NULL, 0);
+ if (!(start <= end)) {
+ free(bitarr);
+ return NULL;
+ }
+
+ if (end >= nbits) {
+ free(bitarr);
+ return NULL;
+ }
+
+ while (start <= end)
+ set_bit(start++, bitarr);
+ }
+
+ return bitarr;
+}
+
+static char *string_join(const char *sep, const char **parts, bool use_as_prefix)
+{
+ char *result;
+ char **p;
+ size_t sep_len = strlen(sep);
+ size_t result_len = use_as_prefix * sep_len;
+
+ if (!parts)
+ return NULL;
+
+ /* calculate new string length */
+ for (p = (char **)parts; *p; p++)
+ result_len += (p > (char **)parts) * sep_len + strlen(*p);
+
+ result = calloc(result_len + 1, sizeof(char));
+ if (!result)
+ return NULL;
+
+ if (use_as_prefix)
+ strcpy(result, sep);
+ for (p = (char **)parts; *p; p++) {
+ if (p > (char **)parts)
+ strcat(result, sep);
+ strcat(result, *p);
+ }
+
+ return result;
+}
+
+/* The largest integer that can fit into long int is 2^64. This is a
+ * 20-digit number.
+ */
+#define __IN_TO_STR_LEN 21
+/* Turn cpumask into simple, comma-separated cpulist. */
+static char *cg_cpumask_to_cpulist(uint32_t *bitarr, size_t nbits)
+{
+ size_t i;
+ int ret;
+ char numstr[__IN_TO_STR_LEN] = {0};
+ char **cpulist = NULL;
+
+ for (i = 0; i <= nbits; i++) {
+ if (is_set(i, bitarr)) {
+ ret = snprintf(numstr, __IN_TO_STR_LEN, "%zu", i);
+ if (ret < 0 || (size_t)ret >= __IN_TO_STR_LEN) {
+ free_string_list(cpulist);
+ return NULL;
+ }
+ must_append_string(&cpulist, numstr);
+ }
+ }
+ return string_join(",", (const char **)cpulist, false);
+}
+
+static ssize_t cg_get_max_cpus(char *cpulist)
+{
+ char *c1, *c2;
+ char *maxcpus = cpulist;
+ size_t cpus = 0;
+
+ c1 = strrchr(maxcpus, ',');
+ if (c1)
+ c1++;
+
+ c2 = strrchr(maxcpus, '-');
+ if (c2)
+ c2++;
+
+ if (!c1 && !c2)
+ c1 = maxcpus;
+ else if (c1 < c2)
+ c1 = c2;
+
+ /* If the above logic is correct, c1 should always hold a valid string
+ * here.
+ */
+
+ errno = 0;
+ cpus = strtoul(c1, NULL, 0);
+ if (errno != 0)
+ return -1;
+
+ return cpus;
+}
+
+static ssize_t write_nointr(int fd, const void* buf, size_t count)
+{
+ ssize_t ret;
+again:
+ ret = write(fd, buf, count);
+ if (ret < 0 && errno == EINTR)
+ goto again;
+ return ret;
+}
+
+static int write_to_file(const char *filename, const void* buf, size_t count, bool add_newline)
+{
+ int fd, saved_errno;
+ ssize_t ret;
+
+ fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, 0666);
+ if (fd < 0)
+ return -1;
+ ret = write_nointr(fd, buf, count);
+ if (ret < 0)
+ goto out_error;
+ if ((size_t)ret != count)
+ goto out_error;
+ if (add_newline) {
+ ret = write_nointr(fd, "\n", 1);
+ if (ret != 1)
+ goto out_error;
+ }
+ close(fd);
+ return 0;
+
+out_error:
+ saved_errno = errno;
+ close(fd);
+ errno = saved_errno;
+ return -1;
+}
+
+#define __ISOL_CPUS "/sys/devices/system/cpu/isolated"
+static bool cg_filter_and_set_cpus(char *path, bool am_initialized)
+{
+ char *lastslash, *fpath, oldv;
+ int ret;
+ ssize_t i;
+
+ ssize_t maxposs = 0, maxisol = 0;
+ char *cpulist = NULL, *posscpus = NULL, *isolcpus = NULL;
+ uint32_t *possmask = NULL, *isolmask = NULL;
+ bool bret = false, flipped_bit = false;
+
+ lastslash = strrchr(path, '/');
+ if (!lastslash) { // bug... this shouldn't be possible
+ pam_cgfs_debug("Invalid path: %s.\n", path);
+ return bret;
+ }
+ oldv = *lastslash;
+ *lastslash = '\0';
+ fpath = must_make_path(path, "cpuset.cpus", NULL);
+ posscpus = read_file(fpath);
+ if (!posscpus) {
+ pam_cgfs_debug("Could not read file: %s.\n", fpath);
+ goto on_error;
+ }
+
+ /* Get maximum number of cpus found in possible cpuset. */
+ maxposs = cg_get_max_cpus(posscpus);
+ if (maxposs < 0)
+ goto on_error;
+
+ if (!file_exists(__ISOL_CPUS)) {
+ /* This system doesn't expose isolated cpus. */
+ pam_cgfs_debug("%s", "Path: "__ISOL_CPUS" to read isolated cpus from does not exist.\n");
+ cpulist = posscpus;
+ /* No isolated cpus but we weren't already initialized by
+ * someone. We should simply copy the parents cpuset.cpus
+ * values.
+ */
+ if (!am_initialized) {
+ pam_cgfs_debug("%s", "Copying cpuset of parent cgroup.\n");
+ goto copy_parent;
+ }
+ /* No isolated cpus but we were already initialized by someone.
+ * Nothing more to do for us.
+ */
+ goto on_success;
+ }
+
+ isolcpus = read_file(__ISOL_CPUS);
+ if (!isolcpus) {
+ pam_cgfs_debug("%s", "Could not read file "__ISOL_CPUS"\n");
+ goto on_error;
+ }
+ if (!isdigit(isolcpus[0])) {
+ pam_cgfs_debug("%s", "No isolated cpus detected.\n");
+ cpulist = posscpus;
+ /* No isolated cpus but we weren't already initialized by
+ * someone. We should simply copy the parents cpuset.cpus
+ * values.
+ */
+ if (!am_initialized) {
+ pam_cgfs_debug("%s", "Copying cpuset of parent cgroup.\n");
+ goto copy_parent;
+ }
+ /* No isolated cpus but we were already initialized by someone.
+ * Nothing more to do for us.
+ */
+ goto on_success;
+ }
+
+ /* Get maximum number of cpus found in isolated cpuset. */
+ maxisol = cg_get_max_cpus(isolcpus);
+ if (maxisol < 0)
+ goto on_error;
+
+ if (maxposs < maxisol)
+ maxposs = maxisol;
+ maxposs++;
+
+ possmask = cg_cpumask(posscpus, maxposs);
+ if (!possmask) {
+ pam_cgfs_debug("%s", "Could not create cpumask for all possible cpus.\n");
+ goto on_error;
+ }
+
+ isolmask = cg_cpumask(isolcpus, maxposs);
+ if (!isolmask) {
+ pam_cgfs_debug("%s", "Could not create cpumask for all isolated cpus.\n");
+ goto on_error;
+ }
+
+ for (i = 0; i <= maxposs; i++) {
+ if (is_set(i, isolmask) && is_set(i, possmask)) {
+ flipped_bit = true;
+ clear_bit(i, possmask);
+ }
+ }
+
+ if (!flipped_bit) {
+ pam_cgfs_debug("%s", "No isolated cpus present in cpuset.\n");
+ goto on_success;
+ }
+ pam_cgfs_debug("%s", "Removed isolated cpus from cpuset.\n");
+
+ cpulist = cg_cpumask_to_cpulist(possmask, maxposs);
+ if (!cpulist) {
+ pam_cgfs_debug("%s", "Could not create cpu list.\n");
+ goto on_error;
+ }
+
+copy_parent:
+ *lastslash = oldv;
+ fpath = must_make_path(path, "cpuset.cpus", NULL);
+ ret = write_to_file(fpath, cpulist, strlen(cpulist), false);
+ if (ret < 0) {
+ pam_cgfs_debug("Could not write cpu list to: %s.\n", fpath);
+ goto on_error;
+ }
+
+on_success:
+ bret = true;
+
+on_error:
+ free(fpath);
+
+ free(isolcpus);
+ free(isolmask);
+
+ if (posscpus != cpulist)
+ free(posscpus);
+ free(possmask);
+
+ free(cpulist);
+ return bret;
+}
+
+int read_from_file(const char *filename, void* buf, size_t count)
+{
+ int fd = -1, saved_errno;
+ ssize_t ret;
+
+ fd = open(filename, O_RDONLY | O_CLOEXEC);
+ if (fd < 0)
+ return -1;
+
+ if (!buf || !count) {
+ char buf2[100];
+ size_t count2 = 0;
+ while ((ret = read(fd, buf2, 100)) > 0)
+ count2 += ret;
+ if (ret >= 0)
+ ret = count2;
+ } else {
+ memset(buf, 0, count);
+ ret = read(fd, buf, count);
+ }
+
+ if (ret < 0)
+ pam_cgfs_debug("read %s: %s", filename, strerror(errno));
+
+ saved_errno = errno;
+ close(fd);
+ errno = saved_errno;
+ return ret;
+}
+
+/* Copy contents of parent(@path)/@file to @path/@file */
+static bool cg_copy_parent_file(char *path, char *file)
+{
+ char *lastslash, *value = NULL, *fpath, oldv;
+ int len = 0;
+ int ret;
+
+ lastslash = strrchr(path, '/');
+ if (!lastslash) { // bug... this shouldn't be possible
+ pam_cgfs_debug("cgfsng:copy_parent_file: bad path %s", path);
+ return false;
+ }
+ oldv = *lastslash;
+ *lastslash = '\0';
+ fpath = must_make_path(path, file, NULL);
+ len = read_from_file(fpath, NULL, 0);
+ if (len <= 0)
+ goto bad;
+ value = must_alloc(len + 1);
+ if (read_from_file(fpath, value, len) != len)
+ goto bad;
+ free(fpath);
+ *lastslash = oldv;
+ fpath = must_make_path(path, file, NULL);
+ ret = write_to_file(fpath, value, len, false);
+ if (ret < 0)
+ pam_cgfs_debug("Unable to write %s to %s", value, fpath);
+ free(fpath);
+ free(value);
+ return ret >= 0;
+
+bad:
+ pam_cgfs_debug("Error reading '%s'", fpath);
+ free(fpath);
+ free(value);
+ return false;
+}
+
+/* In case systemd hasn't already placed us in a user slice for the cpuset v1
+ * controller we will reside in the root cgroup. This means that
+ * cgroup.clone_children will not have been initialized for us so we need to do
+ * it.
+ */
+static bool cgv1_handle_root_cpuset_hierarchy(struct cgv1_hierarchy *h)
+{
+ char *clonechildrenpath, v;
+
+ if (!string_in_list(h->controllers, "cpuset"))
+ return true;
+
+ clonechildrenpath = must_make_path(h->mountpoint, "cgroup.clone_children", NULL);
+
+ if (read_from_file(clonechildrenpath, &v, 1) < 0) {
+ pam_cgfs_debug("Failed to read '%s'", clonechildrenpath);
+ free(clonechildrenpath);
+ return false;
+ }
+
+ if (v == '1') { /* already set for us by someone else */
+ free(clonechildrenpath);
+ return true;
+ }
+
+ if (write_to_file(clonechildrenpath, "1", 1, false) < 0) {
+ /* Set clone_children so children inherit our settings */
+ pam_cgfs_debug("Failed to write 1 to %s", clonechildrenpath);
+ free(clonechildrenpath);
+ return false;
+ }
+ free(clonechildrenpath);
+ return true;
+}
+
+/*
+ * Initialize the cpuset hierarchy in first directory of @gname and
+ * set cgroup.clone_children so that children inherit settings.
+ * Since the h->base_path is populated by init or ourselves, we know
+ * it is already initialized.
+ */
+static bool cgv1_handle_cpuset_hierarchy(struct cgv1_hierarchy *h,
+ const char *cgroup)
+{
+ char *cgpath, *clonechildrenpath, v, *slash;
+
+ if (!string_in_list(h->controllers, "cpuset"))
+ return true;
+
+ if (*cgroup == '/')
+ cgroup++;
+ slash = strchr(cgroup, '/');
+ if (slash)
+ *slash = '\0';
+
+ cgpath = must_make_path(h->mountpoint, h->base_cgroup, cgroup, NULL);
+ if (slash)
+ *slash = '/';
+ if (mkdir(cgpath, 0755) < 0 && errno != EEXIST) {
+ pam_cgfs_debug("Failed to create '%s'", cgpath);
+ free(cgpath);
+ return false;
+ }
+ clonechildrenpath = must_make_path(cgpath, "cgroup.clone_children", NULL);
+ if (!file_exists(clonechildrenpath)) { /* unified hierarchy doesn't have clone_children */
+ free(clonechildrenpath);
+ free(cgpath);
+ return true;
+ }
+ if (read_from_file(clonechildrenpath, &v, 1) < 0) {
+ pam_cgfs_debug("Failed to read '%s'", clonechildrenpath);
+ free(clonechildrenpath);
+ free(cgpath);
+ return false;
+ }
+
+ /* Make sure any isolated cpus are removed from cpuset.cpus. */
+ if (!cg_filter_and_set_cpus(cgpath, v == '1')) {
+ pam_cgfs_debug("%s", "Failed to remove isolated cpus.\n");
+ free(clonechildrenpath);
+ free(cgpath);
+ return false;
+ }
+
+ if (v == '1') { /* already set for us by someone else */
+ pam_cgfs_debug("%s", "\"cgroup.clone_children\" was already set to \"1\".\n");
+ free(clonechildrenpath);
+ free(cgpath);
+ return true;
+ }
+
+ /* copy parent's settings */
+ if (!cg_copy_parent_file(cgpath, "cpuset.mems")) {
+ pam_cgfs_debug("%s", "Failed to copy \"cpuset.mems\" settings.\n");
+ free(cgpath);
+ free(clonechildrenpath);
+ return false;
+ }
+ free(cgpath);
+
+ if (write_to_file(clonechildrenpath, "1", 1, false) < 0) {
+ /* Set clone_children so children inherit our settings */
+ pam_cgfs_debug("Failed to write 1 to %s", clonechildrenpath);
+ free(clonechildrenpath);
+ return false;
+ }
+ free(clonechildrenpath);
+ return true;
+}
+
+/* Create and chown @cgroup for all given controllers in a cgroupfs v1 hierarchy
+ * (For example, create @cgroup for the cpu and cpuacct controller mounted into
+ * /sys/fs/cgroup/cpu,cpuacct). Check if the path already exists and report back
+ * to the caller in @existed.
+ */
+#define __PAM_CGFS_USER "/user/"
+#define __PAM_CGFS_USER_LEN 6
+static bool cgv1_create_one(struct cgv1_hierarchy *h, const char *cgroup, uid_t uid, gid_t gid, bool *existed)
+{
+ char *clean_base_cgroup, *path;
+ char **controller;
+ struct cgv1_hierarchy *it;
+ bool created = false;
+
+ *existed = false;
+ it = h;
+ for (controller = it->controllers; controller && *controller;
+ controller++) {
+ if (!cgv1_handle_cpuset_hierarchy(it, cgroup))
+ return false;
+
+ /* If systemd has already created a cgroup for us, keep using
+ * it.
+ */
+ if (cg_systemd_chown_existing_cgroup(it->mountpoint,
+ it->base_cgroup, uid, gid,
+ it->systemd_user_slice)) {
+ return true;
+ }
+
+ /* We need to make sure that we do not create an endless chain
+ * of sub-cgroups. So we check if we have already logged in
+ * somehow (sudo -i, su, etc.) and have created a
+ * /user/PAM_user/idx cgroup. If so, we skip that part. For most
+ * cgroups this is unnecessary since we use the init_cgroup
+ * anyway, but for controllers which have an existing systemd
+ * cgroup that does not match the current uid, this is pretty
+ * useful.
+ */
+ if (strncmp(it->base_cgroup, __PAM_CGFS_USER, __PAM_CGFS_USER_LEN) == 0) {
+ free(it->base_cgroup);
+ it->base_cgroup = must_copy_string("/");
+ } else {
+ clean_base_cgroup =
+ strstr(it->base_cgroup, __PAM_CGFS_USER);
+ if (clean_base_cgroup)
+ *clean_base_cgroup = '\0';
+ }
+
+ path = must_make_path(it->mountpoint, it->init_cgroup, cgroup, NULL);
+ pam_cgfs_debug("Constructing path: %s.\n", path);
+ if (file_exists(path)) {
+ bool our_cg = cg_belongs_to_uid_gid(path, uid, gid);
+ pam_cgfs_debug("%s existed and does %shave our uid: %d and gid: %d.\n", path, our_cg ? "" : "not ", uid, gid);
+ free(path);
+ if (our_cg)
+ *existed = false;
+ else
+ *existed = true;
+ return our_cg;
+ }
+ created = mkdir_parent(it->mountpoint, path);
+ if (!created) {
+ free(path);
+ continue;
+ }
+ if (chown(path, uid, gid) < 0)
+ mysyslog(LOG_WARNING,
+ "Failed to chown %s to %d:%d: %s.\n", path,
+ (int)uid, (int)gid, strerror(errno), NULL);
+ pam_cgfs_debug("Chowned %s to %d:%d.\n", path, (int)uid, (int)gid);
+ free(path);
+ break;
+ }
+
+ return created;
+}
+
+/* Try to remove @cgroup for all given controllers in a cgroupfs v1 hierarchy
+ * (For example, try to remove @cgroup for the cpu and cpuacct controller
+ * mounted into /sys/fs/cgroup/cpu,cpuacct). Ignores failures.
+ */
+static bool cgv1_remove_one(struct cgv1_hierarchy *h, const char *cgroup)
+{
+
+ char *path;
+
+ /* Better safe than sorry. */
+ if (!h->controllers)
+ return true;
+
+ /* Cgroups created by systemd for us which we re-use won't be removed
+ * here, since we're using init_cgroup + cgroup as path instead of
+ * base_cgroup + cgroup.
+ */
+ path = must_make_path(h->mountpoint, h->init_cgroup, cgroup, NULL);
+ (void)recursive_rmdir(path);
+ free(path);
+
+ return true;
+}
+
+/* Try to remove @cgroup the cgroupfs v2 hierarchy. */
+static bool cgv2_remove(const char *cgroup)
+{
+ struct cgv2_hierarchy *v2;
+ char *path;
+
+ if (!cgv2_hierarchies)
+ return true;
+
+ v2 = *cgv2_hierarchies;
+
+ /* If we reused an already existing cgroup, don't bother trying to
+ * remove (a potentially wrong)/the path.
+ * Cgroups created by systemd for us which we re-use would be removed
+ * here, since we're using base_cgroup + cgroup as path.
+ */
+ if (v2->systemd_user_slice)
+ return true;
+
+ path = must_make_path(v2->mountpoint, v2->base_cgroup, cgroup, NULL);
+ (void)recursive_rmdir(path);
+ free(path);
+
+ return true;
+}
+
+/* Create @cgroup in all detected cgroupfs v1 hierarchy. If the creation fails
+ * for any cgroupfs v1 hierarchy, remove all we have created so far. Report
+ * back, to the caller if the creation failed due to @cgroup already existing
+ * via @existed.
+ */
+static bool cgv1_create(const char *cgroup, uid_t uid, gid_t gid, bool *existed)
+{
+ struct cgv1_hierarchy **it, **rev_it;
+ bool all_created = true;
+
+ for (it = cgv1_hierarchies; it && *it; it++) {
+ if (!(*it)->controllers || !(*it)->mountpoint ||
+ !(*it)->init_cgroup || !(*it)->create_rw_cgroup)
+ continue;
+
+ if (!cgv1_create_one(*it, cgroup, uid, gid, existed)) {
+ all_created = false;
+ break;
+ }
+ }
+
+ if (all_created)
+ return true;
+
+ for (rev_it = cgv1_hierarchies; rev_it && *rev_it && (*rev_it != *it);
+ rev_it++)
+ cgv1_remove_one(*rev_it, cgroup);
+
+ return false;
+}
+
+/* Create @cgroup in the cgroupfs v2 hierarchy. Report back, to the caller if
+ * the creation failed due to @cgroup already existing via @existed.
+ */
+static bool cgv2_create(const char *cgroup, uid_t uid, gid_t gid, bool *existed)
+{
+ int ret;
+ char *clean_base_cgroup;
+ char *path;
+ struct cgv2_hierarchy *v2;
+ bool our_cg = false, created = false;
+
+ *existed = false;
+
+ if (!cgv2_hierarchies || !(*cgv2_hierarchies)->create_rw_cgroup)
+ return true;
+
+ v2 = *cgv2_hierarchies;
+
+ /* We can't be placed under init's cgroup for the v2 hierarchy. We need
+ * to be placed under our current cgroup.
+ */
+ if (cg_systemd_chown_existing_cgroup(v2->mountpoint, v2->base_cgroup,
+ uid, gid, v2->systemd_user_slice))
+ goto delegate_files;
+
+ /* We need to make sure that we do not create an endless chain of
+ * sub-cgroups. So we check if we have already logged in somehow (sudo
+ * -i, su, etc.) and have created a /user/PAM_user/idx cgroup. If so, we
+ * skip that part.
+ */
+ if (strncmp(v2->base_cgroup, __PAM_CGFS_USER, __PAM_CGFS_USER_LEN) == 0) {
+ free(v2->base_cgroup);
+ v2->base_cgroup = must_copy_string("/");
+ } else {
+ clean_base_cgroup = strstr(v2->base_cgroup, __PAM_CGFS_USER);
+ if (clean_base_cgroup)
+ *clean_base_cgroup = '\0';
+ }
+
+ path = must_make_path(v2->mountpoint, v2->base_cgroup, cgroup, NULL);
+ pam_cgfs_debug("Constructing path \"%s\".\n", path);
+ if (file_exists(path)) {
+ our_cg = cg_belongs_to_uid_gid(path, uid, gid);
+ pam_cgfs_debug(
+ "%s existed and does %shave our uid: %d and gid: %d.\n",
+ path, our_cg ? "" : "not ", uid, gid);
+ free(path);
+ if (our_cg) {
+ *existed = false;
+ goto delegate_files;
+ } else {
+ *existed = true;
+ return false;
+ }
+ }
+
+ created = mkdir_parent(v2->mountpoint, path);
+ if (!created) {
+ free(path);
+ return false;
+ }
+
+ /* chown cgroup to user */
+ if (chown(path, uid, gid) < 0)
+ mysyslog(LOG_WARNING, "Failed to chown %s to %d:%d: %s.\n",
+ path, (int)uid, (int)gid, strerror(errno), NULL);
+ else
+ pam_cgfs_debug("Chowned %s to %d:%d.\n", path, (int)uid, (int)gid);
+ free(path);
+
+delegate_files:
+ /* chown cgroup.procs to user */
+ if (v2->systemd_user_slice)
+ path = must_make_path(v2->mountpoint, v2->base_cgroup,
+ "/cgroup.procs", NULL);
+ else
+ path = must_make_path(v2->mountpoint, v2->base_cgroup, cgroup,
+ "/cgroup.procs", NULL);
+ ret = chown(path, uid, gid);
+ if (ret < 0)
+ mysyslog(LOG_WARNING, "Failed to chown %s to %d:%d: %s.\n",
+ path, (int)uid, (int)gid, strerror(errno), NULL);
+ else
+ pam_cgfs_debug("Chowned %s to %d:%d.\n", path, (int)uid, (int)gid);
+ free(path);
+
+ /* chown cgroup.subtree_control to user */
+ if (v2->systemd_user_slice)
+ path = must_make_path(v2->mountpoint, v2->base_cgroup,
+ "/cgroup.subtree_control", NULL);
+ else
+ path = must_make_path(v2->mountpoint, v2->base_cgroup, cgroup,
+ "/cgroup.subtree_control", NULL);
+ ret = chown(path, uid, gid);
+ if (ret < 0)
+ mysyslog(LOG_WARNING, "Failed to chown %s to %d:%d: %s.\n",
+ path, (int)uid, (int)gid, strerror(errno), NULL);
+ free(path);
+
+ /* chown cgroup.threads to user */
+ if (v2->systemd_user_slice)
+ path = must_make_path(v2->mountpoint, v2->base_cgroup,
+ "/cgroup.threads", NULL);
+ else
+ path = must_make_path(v2->mountpoint, v2->base_cgroup, cgroup,
+ "/cgroup.threads", NULL);
+ ret = chown(path, uid, gid);
+ if (ret < 0 && errno != ENOENT)
+ mysyslog(LOG_WARNING, "Failed to chown %s to %d:%d: %s.\n",
+ path, (int)uid, (int)gid, strerror(errno), NULL);
+ free(path);
+
+ return true;
+}
+
+/* Create writeable cgroups for @user at login. Details can be found in the
+ * preamble/license at the top of this file.
+ */
+static int handle_login(const char *user, uid_t uid, gid_t gid)
+{
+ int idx = 0, ret;
+ bool existed;
+ char cg[MAXPATHLEN];
+
+ cg_escape();
+
+ while (idx >= 0) {
+ ret = snprintf(cg, MAXPATHLEN, "/user/%s/%d", user, idx);
+ if (ret < 0 || ret >= MAXPATHLEN) {
+ mysyslog(LOG_ERR, "Username too long.\n", NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ existed = false;
+ if (!cgv2_create(cg, uid, gid, &existed)) {
+ if (existed) {
+ cgv2_remove(cg);
+ idx++;
+ continue;
+ }
+ mysyslog(LOG_ERR, "Failed to create a cgroup for user %s.\n", user, NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ existed = false;
+ if (!cgv1_create(cg, uid, gid, &existed)) {
+ if (existed) {
+ cgv2_remove(cg);
+ idx++;
+ continue;
+ }
+ mysyslog(LOG_ERR, "Failed to create a cgroup for user %s.\n", user, NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ if (!cg_enter(cg)) {
+ mysyslog( LOG_ERR, "Failed to enter user cgroup %s for user %s.\n", cg, user, NULL);
+ return PAM_SESSION_ERR;
+ }
+ break;
+ }
+
+ return PAM_SUCCESS;
+}
+
+/* Try to prune cgroups we created and that now are empty from all cgroupfs v1
+ * hierarchies.
+ */
+static bool cgv1_prune_empty_cgroups(const char *user)
+{
+ bool controller_removed = true;
+ bool all_removed = true;
+ struct cgv1_hierarchy **it;
+
+ for (it = cgv1_hierarchies; it && *it; it++) {
+ int ret;
+ char *path_base, *path_init;
+ char **controller;
+
+ if (!(*it)->controllers || !(*it)->mountpoint ||
+ !(*it)->init_cgroup || !(*it)->create_rw_cgroup)
+ continue;
+
+ for (controller = (*it)->controllers; controller && *controller;
+ controller++) {
+ bool path_base_rm, path_init_rm;
+
+ path_base = must_make_path((*it)->mountpoint, (*it)->base_cgroup, "/user", user, NULL);
+ pam_cgfs_debug("cgroupfs v1: Trying to prune \"%s\".\n", path_base);
+ ret = recursive_rmdir(path_base);
+ if (ret == -ENOENT || ret >= 0)
+ path_base_rm = true;
+ else
+ path_base_rm = false;
+ free(path_base);
+
+ path_init = must_make_path((*it)->mountpoint, (*it)->init_cgroup, "/user", user, NULL);
+ pam_cgfs_debug("cgroupfs v1: Trying to prune \"%s\".\n", path_init);
+ ret = recursive_rmdir(path_init);
+ if (ret == -ENOENT || ret >= 0)
+ path_init_rm = true;
+ else
+ path_init_rm = false;
+ free(path_init);
+
+ if (!path_base_rm && !path_init_rm) {
+ controller_removed = false;
+ continue;
+ }
+
+ controller_removed = true;
+ break;
+ }
+ if (!controller_removed)
+ all_removed = false;
+ }
+
+ return all_removed;
+}
+
+/* Try to prune cgroup we created and that now is empty from the cgroupfs v2
+ * hierarchy.
+ */
+static bool cgv2_prune_empty_cgroups(const char *user)
+{
+ int ret;
+ struct cgv2_hierarchy *v2;
+ char *path_base, *path_init;
+ bool path_base_rm, path_init_rm;
+
+ if (!cgv2_hierarchies)
+ return true;
+
+ v2 = *cgv2_hierarchies;
+
+ path_base = must_make_path(v2->mountpoint, v2->base_cgroup, "/user", user, NULL);
+ pam_cgfs_debug("cgroupfs v2: Trying to prune \"%s\".\n", path_base);
+ ret = recursive_rmdir(path_base);
+ if (ret == -ENOENT || ret >= 0)
+ path_base_rm = true;
+ else
+ path_base_rm = false;
+ free(path_base);
+
+ path_init = must_make_path(v2->mountpoint, v2->init_cgroup, "/user", user, NULL);
+ pam_cgfs_debug("cgroupfs v2: Trying to prune \"%s\".\n", path_init);
+ ret = recursive_rmdir(path_init);
+ if (ret == -ENOENT || ret >= 0)
+ path_init_rm = true;
+ else
+ path_init_rm = false;
+ free(path_init);
+
+ if (!path_base_rm && !path_init_rm)
+ return false;
+
+ return true;
+}
+
+/* Wrapper around cgv{1,2}_prune_empty_cgroups(). */
+static void cg_prune_empty_cgroups(const char *user)
+{
+ (void)cgv1_prune_empty_cgroups(user);
+ (void)cgv2_prune_empty_cgroups(user);
+}
+
+/* Free allocated information for detected cgroupfs v1 hierarchies. */
+static void cgv1_free_hierarchies(void)
+{
+ struct cgv1_hierarchy **it;
+
+ if (!cgv1_hierarchies)
+ return;
+
+ for (it = cgv1_hierarchies; it && *it; it++) {
+ if ((*it)->controllers) {
+ char **tmp;
+ for (tmp = (*it)->controllers; tmp && *tmp; tmp++)
+ free(*tmp);
+
+ free((*it)->controllers);
+ }
+ free((*it)->mountpoint);
+ free((*it)->base_cgroup);
+ free((*it)->fullcgpath);
+ free((*it)->init_cgroup);
+ }
+ free(cgv1_hierarchies);
+}
+
+/* Free allocated information for the detected cgroupfs v2 hierarchy. */
+static void cgv2_free_hierarchies(void)
+{
+ struct cgv2_hierarchy **it;
+
+ if (!cgv2_hierarchies)
+ return;
+
+ for (it = cgv2_hierarchies; it && *it; it++) {
+ if ((*it)->controllers) {
+ char **tmp;
+ for (tmp = (*it)->controllers; tmp && *tmp; tmp++)
+ free(*tmp);
+
+ free((*it)->controllers);
+ }
+ free((*it)->mountpoint);
+ free((*it)->base_cgroup);
+ free((*it)->fullcgpath);
+ free((*it)->init_cgroup);
+ }
+ free(cgv2_hierarchies);
+}
+
+/* Wrapper around cgv{1,2}_free_hierarchies(). */
+static void cg_exit(void)
+{
+ cgv1_free_hierarchies();
+ cgv2_free_hierarchies();
+}
+
+int pam_sm_open_session(pam_handle_t *pamh, int flags, int argc,
+ const char **argv)
+{
+ int ret;
+ uid_t uid = 0;
+ gid_t gid = 0;
+ const char *PAM_user = NULL;
+
+ ret = pam_get_user(pamh, &PAM_user, NULL);
+ if (ret != PAM_SUCCESS) {
+ mysyslog(LOG_ERR, "PAM-CGFS: couldn't get user\n", NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ if (!get_uid_gid(PAM_user, &uid, &gid)) {
+ mysyslog(LOG_ERR, "Failed to get uid and gid for %s.\n", PAM_user, NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ if (!cg_init(uid, gid)) {
+ mysyslog(LOG_ERR, "Failed to get list of controllers\n", NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ /* Try to prune cgroups, that are actually empty but were still marked
+ * as busy by the kernel so we couldn't remove them on session close.
+ */
+ cg_prune_empty_cgroups(PAM_user);
+
+ if (cg_mount_mode == CGROUP_UNKNOWN)
+ return PAM_SESSION_ERR;
+
+ if (argc > 1 && !strcmp(argv[0], "-c")) {
+ char **clist = make_string_list(argv[1], ",");
+
+ /*
+ * We don't allow using "all" and other controllers explicitly because
+ * that simply doesn't make any sense.
+ */
+ if (string_list_length(clist) > 1 && string_in_list(clist, "all")) {
+ mysyslog(LOG_ERR, "Invalid -c option, cannot specify individual controllers alongside 'all'.\n", NULL);
+ free_string_list(clist);
+ return PAM_SESSION_ERR;
+ }
+
+ cg_mark_to_make_rw(clist);
+ free_string_list(clist);
+ }
+
+ return handle_login(PAM_user, uid, gid);
+}
+
+int pam_sm_close_session(pam_handle_t *pamh, int flags, int argc,
+ const char **argv)
+{
+ int ret;
+ uid_t uid = 0;
+ gid_t gid = 0;
+ const char *PAM_user = NULL;
+
+ ret = pam_get_user(pamh, &PAM_user, NULL);
+ if (ret != PAM_SUCCESS) {
+ mysyslog(LOG_ERR, "PAM-CGFS: couldn't get user\n", NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ if (!get_uid_gid(PAM_user, &uid, &gid)) {
+ mysyslog(LOG_ERR, "Failed to get uid and gid for %s.\n", PAM_user, NULL);
+ return PAM_SESSION_ERR;
+ }
+
+ if (cg_mount_mode == CGROUP_UNINITIALIZED) {
+ if (!cg_init(uid, gid))
+ mysyslog(LOG_ERR, "Failed to get list of controllers\n", NULL);
+
+ if (argc > 1 && !strcmp(argv[0], "-c")) {
+ char **clist = make_string_list(argv[1], ",");
+
+ /*
+ * We don't allow using "all" and other controllers explicitly because
+ * that simply doesn't make any sense.
+ */
+ if (string_list_length(clist) > 1 && string_in_list(clist, "all")) {
+ mysyslog(LOG_ERR, "Invalid -c option, cannot specify individual controllers alongside 'all'.\n", NULL);
+ free_string_list(clist);
+ return PAM_SESSION_ERR;
+ }
+
+ cg_mark_to_make_rw(clist);
+ free_string_list(clist);
+ }
+ }
+
+ cg_prune_empty_cgroups(PAM_user);
+ cg_exit();
+
+ return PAM_SUCCESS;
+}
projects / mirror_lxc.git / commitdiff