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Subject[OP] 04-vfs-fix-permission-checking-in-sys_utimensat.patch added to queue-2.6.22.23-op1
Your patch added to queue-2.6.22.23-op1.
If anyone has any objections, please let us know.

http://repo.or.cz/w/linux-2.6.22.y-op-patches.git
git://repo.or.cz/linux-2.6.22.y-op-patches.git

---

From: Miklos Szeredi <mszeredi@suse.cz>
Date: Thu, 1 May 2008 04:34:45 -0700
Subject: [PATCH] vfs: fix permission checking in sys_utimensat

If utimensat() is called with both times set to UTIME_NOW or one of them to
UTIME_NOW and the other to UTIME_OMIT, then it will update the file time
without any permission checking.

I don't think this can be used for anything other than a local DoS, but
could
be quite bewildering at that (e.g. "Why was that large source tree rebuilt
when I didn't modify anything???")

This affects all kernels from 2.6.22, when the utimensat() syscall was
introduced.

Fix by doing the same permission checking as for the "times == NULL" case.

Thanks to Michael Kerrisk, whose utimensat-non-conformances-and-fixes.patch
in
-mm also fixes this (and breaks other stuff), only he didn't realize the
security implications of this bug.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Backported-to-2.6.22.y: Oliver Pinter <oliver.pntr@gmail.com>

diff --git a/fs/utimes.c b/fs/utimes.c
index f28a919..88432eb 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -39,9 +39,14 @@ asmlinkage long sys_utime(char __user *filename, struct
utimbuf __user *times)

#endif

+static bool nsec_special(long nsec)
+{
+ return nsec == UTIME_OMIT || nsec == UTIME_NOW;
+}
+
static bool nsec_valid(long nsec)
{
- if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
+ if (nsec_special(nsec))
return true;

return nsec >= 0 && nsec <= 999999999;
@@ -115,7 +120,15 @@ long do_utimes(int dfd, char __user *filename, struct
timespec *times, int flags
newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
newattrs.ia_valid |= ATTR_MTIME_SET;
}
- } else {
+ }
+
+ /*
+ * If times is NULL or both times are either UTIME_OMIT or
+ * UTIME_NOW, then need to check permissions, because
+ * inode_change_ok() won't do it.
+ */
+ if (!times || (nsec_special(times[0].tv_nsec) &&
+ nsec_special(times[1].tv_nsec))) {
error = -EACCES;
if (IS_IMMUTABLE(inode))
goto dput_and_out;



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