Re: [patch 3/4 v2] vfs: utimensat(): fix error checking for {UTIME_NOW,UTIME_OMIT}case

From: Michael Kerrisk
Date: Wed Jun 04 2008 - 10:51:56 EST


Andrew,

This patch improves the indentation of the previous patch.
(No other changes).

Cheers,

Michael

--- linux-2.6.26-rc4/fs/utimes.c 2008-06-04 13:36:33.000000000 +0200
+++ linux-2.6.26-rc4-utimensat-fix-v4/fs/utimes.c 2008-06-04 13:35:14.000000000 +0200
@@ -40,14 +40,9 @@

#endif

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

return nsec >= 0 && nsec <= 999999999;
@@ -106,7 +101,7 @@
times[1].tv_nsec == UTIME_NOW)
times = NULL;

- /* Don't worry, the checks are done in inode_change_ok() */
+ /* In most cases, the checks are done in inode_change_ok() */
newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
if (times) {
error = -EPERM;
@@ -128,15 +123,26 @@
newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
newattrs.ia_valid |= ATTR_MTIME_SET;
}
- }

- /*
- * 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))) {
+ /*
+ * For the UTIME_OMIT/UTIME_NOW and UTIME_NOW/UTIME_OMIT
+ * cases, we need to make an extra check that is not done by
+ * inode_change_ok().
+ */
+ if (((times[0].tv_nsec == UTIME_NOW &&
+ times[1].tv_nsec == UTIME_OMIT)
+ ||
+ (times[0].tv_nsec == UTIME_OMIT &&
+ times[1].tv_nsec == UTIME_NOW))
+ && !is_owner_or_cap(inode))
+ goto mnt_drop_write_and_out;
+ } else {
+
+ /*
+ * If times is NULL (or both times are UTIME_NOW),
+ * then we need to check permissions, because
+ * inode_change_ok() won't do it.
+ */
error = -EACCES;
if (IS_IMMUTABLE(inode))
goto mnt_drop_write_and_out;


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