diff options
| author | Pan Bian <bianpan2016@163.com> | 2019-02-01 14:21:26 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-23 08:44:27 +0100 |
| commit | 0d456fae1fb567882e95a4f8d5151718b5c8129d (patch) | |
| tree | f779b634ef0074ea0208293c7d401bab20dda6f7 | |
| parent | 5d5a802ec2eb1d271ca22e184641015ae0a7b8b2 (diff) | |
autofs: drop dentry reference only when it is never used
[ Upstream commit 63ce5f552beb9bdb41546b3a26c4374758b21815 ]
autofs_expire_run() calls dput(dentry) to drop the reference count of
dentry. However, dentry is read via autofs_dentry_ino(dentry) after
that. This may result in a use-free-bug. The patch drops the reference
count of dentry only when it is never used.
Link: http://lkml.kernel.org/r/154725122396.11260.16053424107144453867.stgit@pluto-themaw-net
Signed-off-by: Pan Bian <bianpan2016@163.com>
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/autofs4/expire.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index 7a5a598a2d94..0d8b9c4f27f2 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -560,7 +560,6 @@ int autofs4_expire_run(struct super_block *sb, pkt.len = dentry->d_name.len; memcpy(pkt.name, dentry->d_name.name, pkt.len); pkt.name[pkt.len] = '\0'; - dput(dentry); if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) ) ret = -EFAULT; @@ -573,6 +572,8 @@ int autofs4_expire_run(struct super_block *sb, complete_all(&ino->expire_complete); spin_unlock(&sbi->fs_lock); + dput(dentry); + return ret; } |