Messages in this thread Patch in this message | | | Subject | [PATCH 1/3] autofs: drop dentry reference only when it is never used | From | Ian Kent <> | Date | Sat, 12 Jan 2019 08:00:24 +0800 |
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From: Pan Bian <bianpan2016@163.com>
The function 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.
Signed-off-by: Pan Bian <bianpan2016@163.com> Acked-by: Ian Kent <raven@themaw.net> --- fs/autofs/expire.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
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; }
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