diff options
| author | Pan Bian <bianpan2016@163.com> | 2019-02-01 14:21:26 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-02-01 15:46:24 -0800 |
| commit | 63ce5f552beb9bdb41546b3a26c4374758b21815 (patch) | |
| tree | 318f69dfe1f4e61e6f5fc4d5c634389f1167289e /fs/autofs | |
| parent | c27d82f52f75fc9d8d9d40d120d2a96fdeeada5e (diff) | |
| download | lwn-63ce5f552beb9bdb41546b3a26c4374758b21815.tar.gz lwn-63ce5f552beb9bdb41546b3a26c4374758b21815.zip | |
autofs: drop dentry reference only when it is never used
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>
Diffstat (limited to 'fs/autofs')
| -rw-r--r-- | fs/autofs/expire.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/autofs/expire.c b/fs/autofs/expire.c index d441244b79df..28d9c2b1b3bb 100644 --- a/fs/autofs/expire.c +++ b/fs/autofs/expire.c @@ -596,7 +596,6 @@ int autofs_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; @@ -609,6 +608,8 @@ int autofs_expire_run(struct super_block *sb, complete_all(&ino->expire_complete); spin_unlock(&sbi->fs_lock); + dput(dentry); + return ret; } |