tick/sched: Annotate lockless access to last_jiffies_update

[mirror_ubuntu-bionic-kernel.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 83ffd7dccf23e656224954a5fdd5956dc4334e43..c3eff0425b2add20e99c209eef0f2c8697ab2a8a 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -61,6 +61,8 @@
 #include <linux/uidgid.h>
 #include <linux/cred.h>
 
+#include <linux/nospec.h>
+
 #include <linux/kmsg_dump.h>
 /* Move somewhere else to avoid recompiling? */
 #include <generated/utsrelease.h>
@@ -1138,6 +1140,21 @@ out:
 
 DECLARE_RWSEM(uts_sem);
 
+#ifdef COMPAT_UTS_MACHINE
+static char compat_uts_machine[__OLD_UTS_LEN+1] = COMPAT_UTS_MACHINE;
+
+static int __init parse_compat_uts_machine(char *arg)
+{
+       strncpy(compat_uts_machine, arg, __OLD_UTS_LEN);
+       compat_uts_machine[__OLD_UTS_LEN] = 0;
+       return 0;
+}
+early_param("compat_uts_machine", parse_compat_uts_machine);
+
+#undef COMPAT_UTS_MACHINE
+#define COMPAT_UTS_MACHINE compat_uts_machine
+#endif
+
 #ifdef COMPAT_UTS_MACHINE
 #define override_architecture(name) \
        (personality(current->personality) == PER_LINUX32 && \
@@ -1180,18 +1197,19 @@ static int override_release(char __user *release, size_t len)
 
 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
 {
-       int errno = 0;
+       struct new_utsname tmp;
 
        down_read(&uts_sem);
-       if (copy_to_user(name, utsname(), sizeof *name))
-               errno = -EFAULT;
+       memcpy(&tmp, utsname(), sizeof(tmp));
        up_read(&uts_sem);
+       if (copy_to_user(name, &tmp, sizeof(tmp)))
+               return -EFAULT;
 
-       if (!errno && override_release(name->release, sizeof(name->release)))
-               errno = -EFAULT;
-       if (!errno && override_architecture(name))
-               errno = -EFAULT;
-       return errno;
+       if (override_release(name->release, sizeof(name->release)))
+               return -EFAULT;
+       if (override_architecture(name))
+               return -EFAULT;
+       return 0;
 }
 
 #ifdef __ARCH_WANT_SYS_OLD_UNAME
@@ -1200,55 +1218,46 @@ SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
  */
 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
 {
-       int error = 0;
+       struct old_utsname tmp;
 
        if (!name)
                return -EFAULT;
 
        down_read(&uts_sem);
-       if (copy_to_user(name, utsname(), sizeof(*name)))
-               error = -EFAULT;
+       memcpy(&tmp, utsname(), sizeof(tmp));
        up_read(&uts_sem);
+       if (copy_to_user(name, &tmp, sizeof(tmp)))
+               return -EFAULT;
 
-       if (!error && override_release(name->release, sizeof(name->release)))
-               error = -EFAULT;
-       if (!error && override_architecture(name))
-               error = -EFAULT;
-       return error;
+       if (override_release(name->release, sizeof(name->release)))
+               return -EFAULT;
+       if (override_architecture(name))
+               return -EFAULT;
+       return 0;
 }
 
 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
 {
-       int error;
+       struct oldold_utsname tmp = {};
 
        if (!name)
                return -EFAULT;
-       if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
-               return -EFAULT;
 
        down_read(&uts_sem);
-       error = __copy_to_user(&name->sysname, &utsname()->sysname,
-                              __OLD_UTS_LEN);
-       error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
-       error |= __copy_to_user(&name->nodename, &utsname()->nodename,
-                               __OLD_UTS_LEN);
-       error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
-       error |= __copy_to_user(&name->release, &utsname()->release,
-                               __OLD_UTS_LEN);
-       error |= __put_user(0, name->release + __OLD_UTS_LEN);
-       error |= __copy_to_user(&name->version, &utsname()->version,
-                               __OLD_UTS_LEN);
-       error |= __put_user(0, name->version + __OLD_UTS_LEN);
-       error |= __copy_to_user(&name->machine, &utsname()->machine,
-                               __OLD_UTS_LEN);
-       error |= __put_user(0, name->machine + __OLD_UTS_LEN);
+       memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
+       memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
+       memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN);
+       memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN);
+       memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN);
        up_read(&uts_sem);
+       if (copy_to_user(name, &tmp, sizeof(tmp)))
+               return -EFAULT;
 
-       if (!error && override_architecture(name))
-               error = -EFAULT;
-       if (!error && override_release(name->release, sizeof(name->release)))
-               error = -EFAULT;
-       return error ? -EFAULT : 0;
+       if (override_architecture(name))
+               return -EFAULT;
+       if (override_release(name->release, sizeof(name->release)))
+               return -EFAULT;
+       return 0;
 }
 #endif
 
@@ -1262,17 +1271,18 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
 
        if (len < 0 || len > __NEW_UTS_LEN)
                return -EINVAL;
-       down_write(&uts_sem);
        errno = -EFAULT;
        if (!copy_from_user(tmp, name, len)) {
-               struct new_utsname *u = utsname();
+               struct new_utsname *u;
 
+               down_write(&uts_sem);
+               u = utsname();
                memcpy(u->nodename, tmp, len);
                memset(u->nodename + len, 0, sizeof(u->nodename) - len);
                errno = 0;
                uts_proc_notify(UTS_PROC_HOSTNAME);
+               up_write(&uts_sem);
        }
-       up_write(&uts_sem);
        return errno;
 }
 
@@ -1280,8 +1290,9 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
 
 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
 {
-       int i, errno;
+       int i;
        struct new_utsname *u;
+       char tmp[__NEW_UTS_LEN + 1];
 
        if (len < 0)
                return -EINVAL;
@@ -1290,11 +1301,11 @@ SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
        i = 1 + strlen(u->nodename);
        if (i > len)
                i = len;
-       errno = 0;
-       if (copy_to_user(name, u->nodename, i))
-               errno = -EFAULT;
+       memcpy(tmp, u->nodename, i);
        up_read(&uts_sem);
-       return errno;
+       if (copy_to_user(name, tmp, i))
+               return -EFAULT;
+       return 0;
 }
 
 #endif
@@ -1313,17 +1324,18 @@ SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
        if (len < 0 || len > __NEW_UTS_LEN)
                return -EINVAL;
 
-       down_write(&uts_sem);
        errno = -EFAULT;
        if (!copy_from_user(tmp, name, len)) {
-               struct new_utsname *u = utsname();
+               struct new_utsname *u;
 
+               down_write(&uts_sem);
+               u = utsname();
                memcpy(u->domainname, tmp, len);
                memset(u->domainname + len, 0, sizeof(u->domainname) - len);
                errno = 0;
                uts_proc_notify(UTS_PROC_DOMAINNAME);
+               up_write(&uts_sem);
        }
-       up_write(&uts_sem);
        return errno;
 }
 
@@ -1399,6 +1411,7 @@ SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
        if (resource >= RLIM_NLIMITS)
                return -EINVAL;
 
+       resource = array_index_nospec(resource, RLIM_NLIMITS);
        task_lock(current->group_leader);
        x = current->signal->rlim[resource];
        task_unlock(current->group_leader);
@@ -1418,6 +1431,7 @@ COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
        if (resource >= RLIM_NLIMITS)
                return -EINVAL;
 
+       resource = array_index_nospec(resource, RLIM_NLIMITS);
        task_lock(current->group_leader);
        r = current->signal->rlim[resource];
        task_unlock(current->group_leader);
@@ -1868,7 +1882,7 @@ static int validate_prctl_map(struct prctl_mm_map *prctl_map)
        ((unsigned long)prctl_map->__m1 __op                            \
         (unsigned long)prctl_map->__m2) ? 0 : -EINVAL
        error  = __prctl_check_order(start_code, <, end_code);
-       error |= __prctl_check_order(start_data, <, end_data);
+       error |= __prctl_check_order(start_data,<=, end_data);
        error |= __prctl_check_order(start_brk, <=, brk);
        error |= __prctl_check_order(arg_start, <=, arg_end);
        error |= __prctl_check_order(env_start, <=, env_end);
@@ -2190,6 +2204,17 @@ static int propagate_has_child_subreaper(struct task_struct *p, void *data)
        return 1;
 }
 
+int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
+{
+       return -EINVAL;
+}
+
+int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
+                                   unsigned long ctrl)
+{
+       return -EINVAL;
+}
+
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                unsigned long, arg4, unsigned long, arg5)
 {
@@ -2398,6 +2423,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
        case PR_SVE_GET_VL:
                error = SVE_GET_VL();
                break;
+       case PR_GET_SPECULATION_CTRL:
+               if (arg3 || arg4 || arg5)
+                       return -EINVAL;
+               error = arch_prctl_spec_ctrl_get(me, arg2);
+               break;
+       case PR_SET_SPECULATION_CTRL:
+               if (arg4 || arg5)
+                       return -EINVAL;
+               error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
+               break;
        default:
                error = -EINVAL;
                break;