smb: client: validate change notify buffer before copy
SMB2_change_notify called smb2_validate_iov() but ignored the return
code, then kmemdup()ed using server provided OutputBufferOffset/Length.
Check the return of smb2_validate_iov() and bail out on error.
Discovered with help from the ZeroPath security tooling.
Signed-off-by: Joshua Rogers <linux@joshua.hu>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Cc: stable@vger.kernel.org
Fixes: e3e9463414f61 ("smb3: improve SMB3 change notification support")
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index b0739a2..8b4a457 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4054,9 +4054,12 @@ SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
smb_rsp = (struct smb2_change_notify_rsp *)rsp_iov.iov_base;
- smb2_validate_iov(le16_to_cpu(smb_rsp->OutputBufferOffset),
- le32_to_cpu(smb_rsp->OutputBufferLength), &rsp_iov,
+ rc = smb2_validate_iov(le16_to_cpu(smb_rsp->OutputBufferOffset),
+ le32_to_cpu(smb_rsp->OutputBufferLength),
+ &rsp_iov,
sizeof(struct file_notify_information));
+ if (rc)
+ goto cnotify_exit;
*out_data = kmemdup((char *)smb_rsp + le16_to_cpu(smb_rsp->OutputBufferOffset),
le32_to_cpu(smb_rsp->OutputBufferLength), GFP_KERNEL);
