From: Chris Wright <chris@wirex.com>
Patch from Jakub Jelinek <jakub@redhat.com>
make sure setfsuid/setfsgid return values are right. Before
include/linux/security.h was added, setfsuid/setfsgid always returned
old_fsuid, no matter if the fsuid was actually changed or not. With the
default security ops it seems to do the same, because both
security_task_setuid and security_task_post_setuid return 0, but these are
hooks which seem to return 0 on success, -errno on failure, so if some
non-default security hook is installed and ever returns -errno in
setfsuid/setfsgid, -errno will be returned from the syscall instead of the
expected old_fsuid. This makes it hard to distinguish uids 0xfffff001 ..
0xffffffff from errors of security hooks.
kernel/sys.c | 20 +++++++-------------
1 files changed, 7 insertions(+), 13 deletions(-)
diff -puN kernel/sys.c~lsm-4-setfsuid-fix kernel/sys.c
--- 25/kernel/sys.c~lsm-4-setfsuid-fix 2003-06-13 00:55:02.000000000 -0700
+++ 25-akpm/kernel/sys.c 2003-06-13 00:55:02.000000000 -0700
@@ -831,13 +831,11 @@ asmlinkage long sys_getresgid(gid_t *rgi
asmlinkage long sys_setfsuid(uid_t uid)
{
int old_fsuid;
- int retval;
-
- retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
- if (retval)
- return retval;
old_fsuid = current->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 ||
capable(CAP_SETUID))
@@ -850,9 +848,7 @@ asmlinkage long sys_setfsuid(uid_t uid)
current->fsuid = uid;
}
- retval = security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
- if (retval)
- return retval;
+ security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
return old_fsuid;
}
@@ -863,13 +859,11 @@ asmlinkage long sys_setfsuid(uid_t uid)
asmlinkage long sys_setfsgid(gid_t gid)
{
int old_fsgid;
- int retval;
-
- retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS);
- if (retval)
- return retval;
old_fsgid = current->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 ||
capable(CAP_SETGID))
_