From: Paul Eggert <eggert@cs.ucla.edu>
To: 11108@debbugs.gnu.org
Subject: bug#11108: [PATCH] chmod: fix symlink race condition
Date: Tue, 27 Mar 2012 22:28:31 -0700 [thread overview]
Message-ID: <4F72A17F.6010308@cs.ucla.edu> (raw)
This fixes what I hope is an obvious race condition
that can occur if some other process substitutes a
symlink for a non-symlink while chmod is running.
=====
* src/chmod.c (process_file): Don't follow symlink if we
think the file is not a symlink.
---
src/chmod.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/src/chmod.c b/src/chmod.c
index aa4ac77..2e1f1c7 100644
--- a/src/chmod.c
+++ b/src/chmod.c
@@ -268,7 +268,15 @@ process_file (FTS *fts, FTSENT *ent)
if (! S_ISLNK (old_mode))
{
- if (chmodat (fts->fts_cwd_fd, file, new_mode) == 0)
+ /* Use any native support for AT_SYMLINK_NOFOLLOW, to avoid
+ following a symlink if there is a race. */
+ #if HAVE_FCHMODAT || HAVE_LCHMOD
+ int follow_flag = AT_SYMLINK_NOFOLLOW;
+ #else
+ int follow_flag = 0;
+ #endif
+
+ if (fchmodat (fts->fts_cwd_fd, file, new_mode, follow_flag) == 0)
chmod_succeeded = true;
else
{
--
1.7.6.5
next reply other threads:[~2012-03-28 5:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-28 5:28 Paul Eggert [this message]
2012-03-28 7:36 ` bug#11108: [PATCH] chmod: fix symlink race condition Jim Meyering
2012-03-28 18:11 ` Paul Eggert
2012-03-28 19:32 ` Jim Meyering
2012-03-28 20:13 ` Jim Meyering
2012-03-28 20:28 ` Paul Eggert
2024-03-20 19:01 ` Pádraig Brady
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