From: Murphy Zhou <jencce.kernel@gmail.com>
To: linux-cifs@vger.kernel.org
Cc: sfrench@samba.org, longli@microsoft.com,
Murphy Zhou <jencce.kernel@gmail.com>
Subject: [PATCH] fs/cifs/smb2pdu.c: fix buffer free in SMB2_ioctl_free
Date: Thu, 23 May 2019 12:12:43 +0800 [thread overview]
Message-ID: <20190523041243.12340-1-jencce.kernel@gmail.com> (raw)
The 2nd buffer could be NULL even if iov_len is not zero. This can
trigger a panic when handling symlinks. It's easy to reproduce with
LTP fs_racer scripts[1] which are randomly craete/delete/link files
and dirs. Fix this panic by checking if the 2nd buffer is padding
before kfree, like what we do in SMB2_open_free.
[1] https://github.com/linux-test-project/ltp/tree/master/testcases/kernel/fs/racer
Fixes: 2c87d6a ("cifs: Allocate memory for all iovs in smb2_ioctl")
Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
---
fs/cifs/smb2pdu.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 710ceb8..c36f940 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2619,10 +2619,12 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
void
SMB2_ioctl_free(struct smb_rqst *rqst)
{
+ int i;
if (rqst && rqst->rq_iov) {
cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
- if (rqst->rq_iov[1].iov_len)
- kfree(rqst->rq_iov[1].iov_base);
+ for (i = 1; i < rqst->rq_nvec; i++)
+ if (rqst->rq_iov[i].iov_base != smb2_padding)
+ kfree(rqst->rq_iov[i].iov_base);
}
}
--
1.8.3.1
next reply other threads:[~2019-05-23 4:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 4:12 Murphy Zhou [this message]
2019-05-24 0:44 ` [PATCH] fs/cifs/smb2pdu.c: fix buffer free in SMB2_ioctl_free ronnie sahlberg
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