CRED: Separate task security context from task_struct

Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 151 insertions, 115 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index ed5c29c748ac..5d81f07c0150 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -117,7 +117,9 @@ static int set_one_prio(struct task_struct *p, int niceval, int error)
         uid_t euid = current_euid();
         int no_nice;
 
-        if (p->uid != euid && p->euid != euid && !capable(CAP_SYS_NICE)) {
+        if (p->cred->uid  != euid &&
+            p->cred->euid != euid &&
+            !capable(CAP_SYS_NICE)) {
                 error = -EPERM;
                 goto out;
         }
@@ -174,7 +176,7 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)
                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
                         break;
                 case PRIO_USER:
-                        user = current->user;
+                        user = current->cred->user;
                         if (!who)
                                 who = current_uid();
                         else
@@ -182,7 +184,7 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)
                                         goto out_unlock;        /* No processes for this user */
 
                         do_each_thread(g, p)
-                                if (p->uid == who)
+                                if (p->cred->uid == who)
                                         error = set_one_prio(p, niceval, error);
                         while_each_thread(g, p);
                         if (who != current_uid())
@@ -236,7 +238,7 @@ asmlinkage long sys_getpriority(int which, int who)
                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
                         break;
                 case PRIO_USER:
-                        user = current->user;
+                        user = current->cred->user;
                         if (!who)
                                 who = current_uid();
                         else
@@ -244,7 +246,7 @@ asmlinkage long sys_getpriority(int which, int who)
                                         goto out_unlock;        /* No processes for this user */
 
                         do_each_thread(g, p)
-                                if (p->uid == who) {
+                                if (p->cred->uid == who) {
                                         niceval = 20 - task_nice(p);
                                         if (niceval > retval)
                                                 retval = niceval;
@@ -472,8 +474,9 @@ void ctrl_alt_del(void)
  */
 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 {
-        int old_rgid = current->gid;
-        int old_egid = current->egid;
+        struct cred *cred = current->cred;
+        int old_rgid = cred->gid;
+        int old_egid = cred->egid;
         int new_rgid = old_rgid;
         int new_egid = old_egid;
         int retval;
@@ -484,7 +487,7 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 
         if (rgid != (gid_t) -1) {
                 if ((old_rgid == rgid) ||
-                    (current->egid==rgid) ||
+                    (cred->egid == rgid) ||
                     capable(CAP_SETGID))
                         new_rgid = rgid;
                 else
@@ -492,8 +495,8 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
         }
         if (egid != (gid_t) -1) {
                 if ((old_rgid == egid) ||
-                    (current->egid == egid) ||
-                    (current->sgid == egid) ||
+                    (cred->egid == egid) ||
+                    (cred->sgid == egid) ||
                     capable(CAP_SETGID))
                         new_egid = egid;
                 else
@@ -505,10 +508,10 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
         }
         if (rgid != (gid_t) -1 ||
             (egid != (gid_t) -1 && egid != old_rgid))
-                current->sgid = new_egid;
-        current->fsgid = new_egid;
-        current->egid = new_egid;
-        current->gid = new_rgid;
+                cred->sgid = new_egid;
+        cred->fsgid = new_egid;
+        cred->egid = new_egid;
+        cred->gid = new_rgid;
         key_fsgid_changed(current);
         proc_id_connector(current, PROC_EVENT_GID);
         return 0;
@@ -521,7 +524,8 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
  */
 asmlinkage long sys_setgid(gid_t gid)
 {
-        int old_egid = current->egid;
+        struct cred *cred = current->cred;
+        int old_egid = cred->egid;
         int retval;
 
         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
@@ -533,13 +537,13 @@ asmlinkage long sys_setgid(gid_t gid)
                         set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
-                current->gid = current->egid = current->sgid = current->fsgid = gid;
-        } else if ((gid == current->gid) || (gid == current->sgid)) {
+                cred->gid = cred->egid = cred->sgid = cred->fsgid = gid;
+        } else if ((gid == cred->gid) || (gid == cred->sgid)) {
                 if (old_egid != gid) {
                         set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
-                current->egid = current->fsgid = gid;
+                cred->egid = cred->fsgid = gid;
         }
         else
                 return -EPERM;
@@ -570,7 +574,7 @@ static int set_user(uid_t new_ruid, int dumpclear)
                 set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
-        current->uid = new_ruid;
+        current->cred->uid = new_ruid;
         return 0;
 }
 
@@ -591,6 +595,7 @@ static int set_user(uid_t new_ruid, int dumpclear)
  */
 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 {
+        struct cred *cred = current->cred;
         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
         int retval;
 
@@ -598,14 +603,14 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
         if (retval)
                 return retval;
 
-        new_ruid = old_ruid = current->uid;
-        new_euid = old_euid = current->euid;
-        old_suid = current->suid;
+        new_ruid = old_ruid = cred->uid;
+        new_euid = old_euid = cred->euid;
+        old_suid = cred->suid;
 
         if (ruid != (uid_t) -1) {
                 new_ruid = ruid;
                 if ((old_ruid != ruid) &&
-                    (current->euid != ruid) &&
+                    (cred->euid != ruid) &&
                     !capable(CAP_SETUID))
                         return -EPERM;
         }
@@ -613,8 +618,8 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
         if (euid != (uid_t) -1) {
                 new_euid = euid;
                 if ((old_ruid != euid) &&
-                    (current->euid != euid) &&
-                    (current->suid != euid) &&
+                    (cred->euid != euid) &&
+                    (cred->suid != euid) &&
                     !capable(CAP_SETUID))
                         return -EPERM;
         }
@@ -626,11 +631,11 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
                 set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
-        current->fsuid = current->euid = new_euid;
+        cred->fsuid = cred->euid = new_euid;
         if (ruid != (uid_t) -1 ||
             (euid != (uid_t) -1 && euid != old_ruid))
-                current->suid = current->euid;
-        current->fsuid = current->euid;
+                cred->suid = cred->euid;
+        cred->fsuid = cred->euid;
 
         key_fsuid_changed(current);
         proc_id_connector(current, PROC_EVENT_UID);
@@ -653,7 +658,8 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
  */
 asmlinkage long sys_setuid(uid_t uid)
 {
-        int old_euid = current->euid;
+        struct cred *cred = current->cred;
+        int old_euid = cred->euid;
         int old_ruid, old_suid, new_suid;
         int retval;
 
@@ -661,23 +667,23 @@ asmlinkage long sys_setuid(uid_t uid)
         if (retval)
                 return retval;
 
-        old_ruid = current->uid;
-        old_suid = current->suid;
+        old_ruid = cred->uid;
+        old_suid = cred->suid;
         new_suid = old_suid;
         
         if (capable(CAP_SETUID)) {
                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
                         return -EAGAIN;
                 new_suid = uid;
-        } else if ((uid != current->uid) && (uid != new_suid))
+        } else if ((uid != cred->uid) && (uid != new_suid))
                 return -EPERM;
 
         if (old_euid != uid) {
                 set_dumpable(current->mm, suid_dumpable);
                 smp_wmb();
         }
-        current->fsuid = current->euid = uid;
-        current->suid = new_suid;
+        cred->fsuid = cred->euid = uid;
+        cred->suid = new_suid;
 
         key_fsuid_changed(current);
         proc_id_connector(current, PROC_EVENT_UID);
@@ -692,9 +698,10 @@ asmlinkage long sys_setuid(uid_t uid)
  */
 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 {
-        int old_ruid = current->uid;
-        int old_euid = current->euid;
-        int old_suid = current->suid;
+        struct cred *cred = current->cred;
+        int old_ruid = cred->uid;
+        int old_euid = cred->euid;
+        int old_suid = cred->suid;
         int retval;
 
         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
@@ -702,30 +709,31 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
                 return retval;
 
         if (!capable(CAP_SETUID)) {
-                if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
-                    (ruid != current->euid) && (ruid != current->suid))
+                if ((ruid != (uid_t) -1) && (ruid != cred->uid) &&
+                    (ruid != cred->euid) && (ruid != cred->suid))
                         return -EPERM;
-                if ((euid != (uid_t) -1) && (euid != current->uid) &&
-                    (euid != current->euid) && (euid != current->suid))
+                if ((euid != (uid_t) -1) && (euid != cred->uid) &&
+                    (euid != cred->euid) && (euid != cred->suid))
                         return -EPERM;
-                if ((suid != (uid_t) -1) && (suid != current->uid) &&
-                    (suid != current->euid) && (suid != current->suid))
+                if ((suid != (uid_t) -1) && (suid != cred->uid) &&
+                    (suid != cred->euid) && (suid != cred->suid))
                         return -EPERM;
         }
         if (ruid != (uid_t) -1) {
-                if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
+                if (ruid != cred->uid &&
+                    set_user(ruid, euid != cred->euid) < 0)
                         return -EAGAIN;
         }
         if (euid != (uid_t) -1) {
-                if (euid != current->euid) {
+                if (euid != cred->euid) {
                         set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
-                current->euid = euid;
+                cred->euid = euid;
         }
-        current->fsuid = current->euid;
+        cred->fsuid = cred->euid;
         if (suid != (uid_t) -1)
-                current->suid = suid;
+                cred->suid = suid;
 
         key_fsuid_changed(current);
         proc_id_connector(current, PROC_EVENT_UID);
@@ -735,11 +743,12 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 
 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 {
+        struct cred *cred = current->cred;
         int retval;
 
-        if (!(retval = put_user(current->uid, ruid)) &&
-            !(retval = put_user(current->euid, euid)))
-                retval = put_user(current->suid, suid);
+        if (!(retval = put_user(cred->uid, ruid)) &&
+            !(retval = put_user(cred->euid, euid)))
+                retval = put_user(cred->suid, suid);
 
         return retval;
 }
@@ -749,6 +758,7 @@ asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __us
  */
 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 {
+        struct cred *cred = current->cred;
         int retval;
 
         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
@@ -756,28 +766,28 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
                 return retval;
 
         if (!capable(CAP_SETGID)) {
-                if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
-                    (rgid != current->egid) && (rgid != current->sgid))
+                if ((rgid != (gid_t) -1) && (rgid != cred->gid) &&
+                    (rgid != cred->egid) && (rgid != cred->sgid))
                         return -EPERM;
-                if ((egid != (gid_t) -1) && (egid != current->gid) &&
-                    (egid != current->egid) && (egid != current->sgid))
+                if ((egid != (gid_t) -1) && (egid != cred->gid) &&
+                    (egid != cred->egid) && (egid != cred->sgid))
                         return -EPERM;
-                if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
-                    (sgid != current->egid) && (sgid != current->sgid))
+                if ((sgid != (gid_t) -1) && (sgid != cred->gid) &&
+                    (sgid != cred->egid) && (sgid != cred->sgid))
                         return -EPERM;
         }
         if (egid != (gid_t) -1) {
-                if (egid != current->egid) {
+                if (egid != cred->egid) {
                         set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
-                current->egid = egid;
+                cred->egid = egid;
         }
-        current->fsgid = current->egid;
+        cred->fsgid = cred->egid;
         if (rgid != (gid_t) -1)
-                current->gid = rgid;
+                cred->gid = rgid;
         if (sgid != (gid_t) -1)
-                current->sgid = sgid;
+                cred->sgid = sgid;
 
         key_fsgid_changed(current);
         proc_id_connector(current, PROC_EVENT_GID);
@@ -786,11 +796,12 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 
 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 {
+        struct cred *cred = current->cred;
         int retval;
 
-        if (!(retval = put_user(current->gid, rgid)) &&
-            !(retval = put_user(current->egid, egid)))
-                retval = put_user(current->sgid, sgid);
+        if (!(retval = put_user(cred->gid, rgid)) &&
+            !(retval = put_user(cred->egid, egid)))
+                retval = put_user(cred->sgid, sgid);
 
         return retval;
 }
@@ -804,20 +815,21 @@ asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __us
  */
 asmlinkage long sys_setfsuid(uid_t uid)
 {
+        struct cred *cred = current->cred;
         int old_fsuid;
 
-        old_fsuid = current->fsuid;
+        old_fsuid = cred->fsuid;
         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
                 return old_fsuid;
 
-        if (uid == current->uid || uid == current->euid ||
-            uid == current->suid || uid == current->fsuid || 
+        if (uid == cred->uid || uid == cred->euid ||
+            uid == cred->suid || uid == cred->fsuid ||
             capable(CAP_SETUID)) {
                 if (uid != old_fsuid) {
                         set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
-                current->fsuid = uid;
+                cred->fsuid = uid;
         }
 
         key_fsuid_changed(current);
@@ -833,20 +845,21 @@ asmlinkage long sys_setfsuid(uid_t uid)
  */
 asmlinkage long sys_setfsgid(gid_t gid)
 {
+        struct cred *cred = current->cred;
         int old_fsgid;
 
-        old_fsgid = current->fsgid;
+        old_fsgid = cred->fsgid;
         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
                 return old_fsgid;
 
-        if (gid == current->gid || gid == current->egid ||
-            gid == current->sgid || gid == current->fsgid || 
+        if (gid == cred->gid || gid == cred->egid ||
+            gid == cred->sgid || gid == cred->fsgid ||
             capable(CAP_SETGID)) {
                 if (gid != old_fsgid) {
                         set_dumpable(current->mm, suid_dumpable);
                         smp_wmb();
                 }
-                current->fsgid = gid;
+                cred->fsgid = gid;
                 key_fsgid_changed(current);
                 proc_id_connector(current, PROC_EVENT_GID);
         }
@@ -1208,8 +1221,15 @@ int groups_search(struct group_info *group_info, gid_t grp)
         return 0;
 }
 
-/* validate and set current->group_info */
-int set_current_groups(struct group_info *group_info)
+/**
+ * set_groups - Change a group subscription in a security record
+ * @sec: The security record to alter
+ * @group_info: The group list to impose
+ *
+ * Validate a group subscription and, if valid, impose it upon a task security
+ * record.
+ */
+int set_groups(struct cred *cred, struct group_info *group_info)
 {
         int retval;
         struct group_info *old_info;
@@ -1221,20 +1241,34 @@ int set_current_groups(struct group_info *group_info)
         groups_sort(group_info);
         get_group_info(group_info);
 
-        task_lock(current);
-        old_info = current->group_info;
-        current->group_info = group_info;
-        task_unlock(current);
+        spin_lock(&cred->lock);
+        old_info = cred->group_info;
+        cred->group_info = group_info;
+        spin_unlock(&cred->lock);
 
         put_group_info(old_info);
-
         return 0;
 }
 
+EXPORT_SYMBOL(set_groups);
+
+/**
+ * set_current_groups - Change current's group subscription
+ * @group_info: The group list to impose
+ *
+ * Validate a group subscription and, if valid, impose it upon current's task
+ * security record.
+ */
+int set_current_groups(struct group_info *group_info)
+{
+        return set_groups(current->cred, group_info);
+}
+
 EXPORT_SYMBOL(set_current_groups);
 
 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
 {
+        struct cred *cred = current->cred;
         int i = 0;
 
         /*
@@ -1246,13 +1280,13 @@ asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
                 return -EINVAL;
 
         /* no need to grab task_lock here; it cannot change */
-        i = current->group_info->ngroups;
+        i = cred->group_info->ngroups;
         if (gidsetsize) {
                 if (i > gidsetsize) {
                         i = -EINVAL;
                         goto out;
                 }
-                if (groups_to_user(grouplist, current->group_info)) {
+                if (groups_to_user(grouplist, cred->group_info)) {
                         i = -EFAULT;
                         goto out;
                 }
@@ -1296,9 +1330,10 @@ asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
  */
 int in_group_p(gid_t grp)
 {
+        struct cred *cred = current->cred;
         int retval = 1;
-        if (grp != current->fsgid)
-                retval = groups_search(current->group_info, grp);
+        if (grp != cred->fsgid)
+                retval = groups_search(cred->group_info, grp);
         return retval;
 }
 
@@ -1306,9 +1341,10 @@ EXPORT_SYMBOL(in_group_p);
 
 int in_egroup_p(gid_t grp)
 {
+        struct cred *cred = current->cred;
         int retval = 1;
-        if (grp != current->egid)
-                retval = groups_search(current->group_info, grp);
+        if (grp != cred->egid)
+                retval = groups_search(cred->group_info, grp);
         return retval;
 }
 
@@ -1624,7 +1660,9 @@ asmlinkage long sys_umask(int mask)
 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                           unsigned long arg4, unsigned long arg5)
 {
-        long error = 0;
+        struct task_struct *me = current;
+        unsigned char comm[sizeof(me->comm)];
+        long error;
 
         if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
                 return error;
@@ -1635,39 +1673,41 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                                 error = -EINVAL;
                                 break;
                         }
-                        current->pdeath_signal = arg2;
+                        me->pdeath_signal = arg2;
+                        error = 0;
                         break;
                 case PR_GET_PDEATHSIG:
-                        error = put_user(current->pdeath_signal, (int __user *)arg2);
+                        error = put_user(me->pdeath_signal, (int __user *)arg2);
                         break;
                 case PR_GET_DUMPABLE:
-                        error = get_dumpable(current->mm);
+                        error = get_dumpable(me->mm);
                         break;
                 case PR_SET_DUMPABLE:
                         if (arg2 < 0 || arg2 > 1) {
                                 error = -EINVAL;
                                 break;
                         }
-                        set_dumpable(current->mm, arg2);
+                        set_dumpable(me->mm, arg2);
+                        error = 0;
                         break;
 
                 case PR_SET_UNALIGN:
-                        error = SET_UNALIGN_CTL(current, arg2);
+                        error = SET_UNALIGN_CTL(me, arg2);
                         break;
                 case PR_GET_UNALIGN:
-                        error = GET_UNALIGN_CTL(current, arg2);
+                        error = GET_UNALIGN_CTL(me, arg2);
                         break;
                 case PR_SET_FPEMU:
-                        error = SET_FPEMU_CTL(current, arg2);
+                        error = SET_FPEMU_CTL(me, arg2);
                         break;
                 case PR_GET_FPEMU:
-                        error = GET_FPEMU_CTL(current, arg2);
+                        error = GET_FPEMU_CTL(me, arg2);
                         break;
                 case PR_SET_FPEXC:
-                        error = SET_FPEXC_CTL(current, arg2);
+                        error = SET_FPEXC_CTL(me, arg2);
                         break;
                 case PR_GET_FPEXC:
-                        error = GET_FPEXC_CTL(current, arg2);
+                        error = GET_FPEXC_CTL(me, arg2);
                         break;
                 case PR_GET_TIMING:
                         error = PR_TIMING_STATISTICAL;
@@ -1675,33 +1715,28 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                 case PR_SET_TIMING:
                         if (arg2 != PR_TIMING_STATISTICAL)
                                 error = -EINVAL;
+                        else
+                                error = 0;
                         break;
 
-                case PR_SET_NAME: {
-                        struct task_struct *me = current;
-                        unsigned char ncomm[sizeof(me->comm)];
-
-                        ncomm[sizeof(me->comm)-1] = 0;
-                        if (strncpy_from_user(ncomm, (char __user *)arg2,
-                                                sizeof(me->comm)-1) < 0)
+                case PR_SET_NAME:
+                        comm[sizeof(me->comm)-1] = 0;
+                        if (strncpy_from_user(comm, (char __user *)arg2,
+                                              sizeof(me->comm) - 1) < 0)
                                 return -EFAULT;
-                        set_task_comm(me, ncomm);
+                        set_task_comm(me, comm);
                         return 0;
-                }
-                case PR_GET_NAME: {
-                        struct task_struct *me = current;
-                        unsigned char tcomm[sizeof(me->comm)];
-
-                        get_task_comm(tcomm, me);
-                        if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
+                case PR_GET_NAME:
+                        get_task_comm(comm, me);
+                        if (copy_to_user((char __user *)arg2, comm,
+                                         sizeof(comm)))
                                 return -EFAULT;
                         return 0;
-                }
                 case PR_GET_ENDIAN:
-                        error = GET_ENDIAN(current, arg2);
+                        error = GET_ENDIAN(me, arg2);
                         break;
                 case PR_SET_ENDIAN:
-                        error = SET_ENDIAN(current, arg2);
+                        error = SET_ENDIAN(me, arg2);
                         break;
 
                 case PR_GET_SECCOMP:
@@ -1725,6 +1760,7 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                                         current->default_timer_slack_ns;
                         else
                                 current->timer_slack_ns = arg2;
+                        error = 0;
                         break;
                 default:
                         error = -EINVAL;