Linux 3.8 compat: Use kuid_t/kgid_t when required

When CONFIG_UIDGID_STRICT_TYPE_CHECKS is enabled uid_t/git_t are
replaced by kuid_t/kgid_t, which are structures instead of integral
types. This causes any code that uses an integral type to fail to build.
The User Namespace functionality introduced in Linux 3.8 requires
CONFIG_UIDGID_STRICT_TYPE_CHECKS, so we could not build against any
kernel that supported it.

We resolve this by converting between the new kuid_t/kgid_t structures
and the original uid_t/gid_t types.

Original-patch-by: DHE
Rewrite-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #260

diff --git a/config/spl-build.m4 b/config/spl-build.m4
index da179e33dd62dad9819ec439c61fcfb781275e75..f54c5b166bb8eac72143d7d6988608dcbbecbc60 100644 (file)
--- a/config/spl-build.m4
+++ b/config/spl-build.m4
@@ -73,6 +73,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
        SPL_AC_INODE_TRUNCATE_RANGE
        SPL_AC_FS_STRUCT_SPINLOCK
        SPL_AC_CRED_STRUCT
+       SPL_AC_KUIDGID_T
        SPL_AC_GROUPS_SEARCH
        SPL_AC_PUT_TASK_STRUCT
        SPL_AC_5ARGS_PROC_HANDLER
@@ -1866,6 +1867,36 @@ AC_DEFUN([SPL_AC_CRED_STRUCT], [
        ])
 ])
 
+
+dnl #
+dnl # User namespaces, use kuid_t in place of uid_t
+dnl # where available. Not strictly a user namespaces thing
+dnl # but it should prevent surprises
+dnl #
+AC_DEFUN([SPL_AC_KUIDGID_T], [
+       AC_MSG_CHECKING([whether kuid_t/kgid_t is available])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/uidgid.h>
+       ], [
+               kuid_t userid = KUIDT_INIT(0);
+               kgid_t groupid = KGIDT_INIT(0);
+       ],[
+               SPL_LINUX_TRY_COMPILE([
+                       #include <linux/uidgid.h>
+               ], [
+                       kuid_t userid = 0;
+                       kgid_t groupid = 0;
+               ],[
+                       AC_MSG_RESULT(yes; optional)
+               ],[
+                       AC_MSG_RESULT(yes; mandatory)
+                       AC_DEFINE(HAVE_KUIDGID_T, 1, [kuid_t/kgid_t in use])
+               ])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
 dnl #
 dnl # Custom SPL patch may export this symbol.
 dnl #
@@ -1873,8 +1904,15 @@ AC_DEFUN([SPL_AC_GROUPS_SEARCH],
        [AC_MSG_CHECKING([whether groups_search() is available])
        SPL_LINUX_TRY_COMPILE_SYMBOL([
                #include <linux/cred.h>
+               #ifdef HAVE_KUIDGID_T
+               #include <linux/uidgid.h>
+               #endif
        ], [
+               #ifdef HAVE_KUIDGID_T
+               groups_search(NULL, KGIDT_INIT(0));
+               #else
                groups_search(NULL, 0);
+               #endif
        ], [groups_search], [], [
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_GROUPS_SEARCH, 1, [groups_search() is available])

diff --git a/include/sys/cred.h b/include/sys/cred.h
index 6c905884b9db0149abc7cccf72d2961524e305ae..3ba5c141b966f7494cf5c23ecc513176366b263a 100644 (file)
--- a/include/sys/cred.h
+++ b/include/sys/cred.h
@@ -45,6 +45,36 @@ typedef struct task_struct cred_t;
 
 #endif /* HAVE_CRED_STRUCT */
 
+#ifdef HAVE_KUIDGID_T
+
+ /*
+  * Linux 3.8+ uses typedefs to redefine uid_t and gid_t. We have to rename the
+  * typedefs to recover the original types. We then can use them provided that
+  * we are careful about translating from k{g,u}id_t to the original versions
+  * and vice versa.
+  */
+ #define uid_t xuid_t
+ #define gid_t xgid_t
+ #include <linux/uidgid.h>
+ #undef uid_t
+ #undef gid_t
+
+ #define KUID_TO_SUID(x) (__kuid_val(x))
+ #define KGID_TO_SGID(x) (__kgid_val(x))
+ #define SUID_TO_KUID(x) (KUIDT_INIT(x))
+ #define SGID_TO_KGID(x) (KGIDT_INIT(x))
+ #define KGIDP_TO_SGIDP(x) (&(x)->val)
+
+#else /* HAVE_KUIDGID_T */
+
+ #define KUID_TO_SUID(x) (x)
+ #define KGID_TO_SGID(x) (x)
+ #define SUID_TO_KUID(x) (x)
+ #define SGID_TO_KGID(x) (x)
+ #define KGIDP_TO_SGIDP(x) (x)
+
+#endif /* HAVE_KUIDGID_T */
+
 extern void crhold(cred_t *cr);
 extern void crfree(cred_t *cr);
 extern uid_t crgetuid(const cred_t *cr);

diff --git a/module/spl/spl-cred.c b/module/spl/spl-cred.c
index e669cbf5d8167d602760daff9bb6405bcdce55a9..0ed65725eb53a9dcab10e77dc47b0bf49c6051a0 100644 (file)
--- a/module/spl/spl-cred.c
+++ b/module/spl/spl-cred.c
@@ -38,7 +38,11 @@
 #else
 /* Implementation from 2.6.30 kernel */
 static int
+#ifdef HAVE_KUIDGID_T
+cr_groups_search(const struct group_info *group_info, kgid_t grp)
+#else
 cr_groups_search(const struct group_info *group_info, gid_t grp)
+#endif
 {
        unsigned int left, right;
 
@@ -49,7 +53,7 @@ cr_groups_search(const struct group_info *group_info, gid_t grp)
        right = group_info->ngroups;
        while (left < right) {
                unsigned int mid = (left+right)/2;
-               int cmp = grp - GROUP_AT(group_info, mid);
+               int cmp = KGID_TO_SGID(grp) - KGID_TO_SGID(GROUP_AT(group_info, mid));
                if (cmp > 0)
                        left = mid + 1;
                else if (cmp < 0)
@@ -110,7 +114,7 @@ crgetgroups(const cred_t *cr)
        gid_t *gids;
 
        gi = get_group_info(cr->group_info);
-       gids = gi->blocks[0];
+       gids = KGIDP_TO_SGIDP(gi->blocks[0]);
        put_group_info(gi);
 
        return gids;
@@ -124,7 +128,7 @@ groupmember(gid_t gid, const cred_t *cr)
        int rc;
 
        gi = get_group_info(cr->group_info);
-       rc = cr_groups_search(cr->group_info, gid);
+       rc = cr_groups_search(cr->group_info, SGID_TO_KGID(gid));
        put_group_info(gi);
 
        return rc;
@@ -180,7 +184,7 @@ crgetgroups(const cred_t *cr)
                task_lock((struct task_struct *)cr);
 
        get_group_info(cr->group_info);
-       gids = cr->group_info->blocks[0];
+       gids = KGID_TO_SGID(cr->group_info->blocks[0]);
        put_group_info(cr->group_info);
 
        if (lock)
@@ -215,56 +219,56 @@ groupmember(gid_t gid, const cred_t *cr)
 uid_t
 crgetuid(const cred_t *cr)
 {
-       return cr->euid;
+       return KUID_TO_SUID(cr->euid);
 }
 
 /* Return the real user id */
 uid_t
 crgetruid(const cred_t *cr)
 {
-       return cr->uid;
+       return KUID_TO_SUID(cr->uid);
 }
 
 /* Return the saved user id */
 uid_t
 crgetsuid(const cred_t *cr)
 {
-       return cr->suid;
+       return KUID_TO_SUID(cr->suid);
 }
 
 /* Return the filesystem user id */
 uid_t
 crgetfsuid(const cred_t *cr)
 {
-       return cr->fsuid;
+       return KUID_TO_SUID(cr->fsuid);
 }
 
 /* Return the effective group id */
 gid_t
 crgetgid(const cred_t *cr)
 {
-       return cr->egid;
+       return KGID_TO_SGID(cr->egid);
 }
 
 /* Return the real group id */
 gid_t
 crgetrgid(const cred_t *cr)
 {
-       return cr->gid;
+       return KGID_TO_SGID(cr->gid);
 }
 
 /* Return the saved group id */
 gid_t
 crgetsgid(const cred_t *cr)
 {
-       return cr->sgid;
+       return KGID_TO_SGID(cr->sgid);
 }
 
 /* Return the filesystem group id */
 gid_t
 crgetfsgid(const cred_t *cr)
 {
-       return cr->fsgid;
+       return KGID_TO_SGID(cr->fsgid);
 }
 
 EXPORT_SYMBOL(crhold);

diff --git a/module/spl/spl-vnode.c b/module/spl/spl-vnode.c
index 4f56f1039ae14ed72654a2bb23690b3e67049c03..0784ff2611096304b532901b01b2559c4ae1453b 100644 (file)
--- a/module/spl/spl-vnode.c
+++ b/module/spl/spl-vnode.c
@@ -24,6 +24,7 @@
  *  Solaris Porting Layer (SPL) Vnode Implementation.
 \*****************************************************************************/
 
+#include <sys/cred.h>
 #include <sys/vnode.h>
 #include <linux/falloc.h>
 #include <spl-debug.h>
@@ -616,8 +617,8 @@ vn_getattr(vnode_t *vp, vattr_t *vap, int flags, void *x3, void *x4)
 
        vap->va_type          = vn_mode_to_vtype(stat.mode);
        vap->va_mode          = stat.mode;
-       vap->va_uid           = stat.uid;
-       vap->va_gid           = stat.gid;
+       vap->va_uid           = KUID_TO_SUID(stat.uid);
+       vap->va_gid           = KGID_TO_SGID(stat.gid);
        vap->va_fsid          = 0;
        vap->va_nodeid        = stat.ino;
        vap->va_nlink         = stat.nlink;