From: Murphy Zhou <jencce.kernel@gmail.com>
Date: Thu, 23 May 2019 12:12:43 +0800
Subject: [PATCH] fs/cifs/smb2pdu.c: fix buffer free in SMB2_ioctl_free
Git-commit: 6457c20e336867fc90286d35bddcc9c0b0aaa936
Patch-mainline: v5.2-rc3
References: bsc#1144333
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: 2c87d6a94d16 ("cifs: Allocate memory for all iovs in smb2_ioctl")
Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie sahlberg <lsahlber@redhat.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
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 5b8d1482ffbd..29b699d532ef 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2620,10 +2620,12 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
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);
}
}
--
2.22.0