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authorIan Kent <raven@themaw.net>2008-07-23 21:30:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:32 -0700
commit5a11d4d0ee1ff284271f7265929d07ea4a1168a6 (patch)
tree4b9b76486afa5d9fc29216df069c5a557e09011a /fs/autofs4/waitq.c
parent70b52a0a5005ce6a0ceec56e97222437a0ba7506 (diff)
downloadvexpress-lsk-5a11d4d0ee1ff284271f7265929d07ea4a1168a6.tar.gz
autofs4: fix waitq locking
The autofs4_catatonic_mode() function accesses the wait queue without any locking but can be called at any time. This could lead to a possible double free of the name field of the wait and a double fput of the daemon communication pipe or an fput of a NULL file pointer. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/autofs4/waitq.c')
-rw-r--r--fs/autofs4/waitq.c23
1 files changed, 12 insertions, 11 deletions
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 5208cfb1df4..55aac10cf32 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -28,6 +28,12 @@ void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
{
struct autofs_wait_queue *wq, *nwq;
+ mutex_lock(&sbi->wq_mutex);
+ if (sbi->catatonic) {
+ mutex_unlock(&sbi->wq_mutex);
+ return;
+ }
+
DPRINTK("entering catatonic mode");
sbi->catatonic = 1;
@@ -45,6 +51,8 @@ void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
}
fput(sbi->pipe); /* Close the pipe */
sbi->pipe = NULL;
+ sbi->pipefd = -1;
+ mutex_unlock(&sbi->wq_mutex);
}
static int autofs4_write(struct file *file, const void *addr, int bytes)
@@ -333,17 +341,10 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
wq->name.name, notify);
}
- /* wq->name is NULL if and only if the lock is already released */
-
- if (sbi->catatonic) {
- /* We might have slept, so check again for catatonic mode */
- wq->status = -ENOENT;
- if (wq->name.name) {
- kfree(wq->name.name);
- wq->name.name = NULL;
- }
- }
-
+ /*
+ * wq->name.name is NULL iff the lock is already released
+ * or the mount has been made catatonic.
+ */
if (wq->name.name) {
/* Block all but "shutdown" signals while waiting */
sigset_t oldset;