Wouldn't it be safer to just set the size, instead of implicitly
assuming that there are 4 array elements?
inbuflen = sizeof(*pneg_inbuf) - sizeof(pneg_inbuf.Dialects) +
sizeof(pneg_inbuf.Dialects[0]);
Or, because it obviously works to send the extra bytes even
though the DialectCount is just 1, just zero them out?
memset(pneg_inbuf.Dialects, 0, sizeof(pneg_inbuf.Dialects));
pneg_inbuf.Dialects[0] = cpu_to_le16(server->vals->protocol_id);
Tom.
On 8/30/2022 3:06 AM, huaweicloud wrote:
Hi Steve,
Could you help to review this patch.
Thanks,
Zhang Xiaoxu
在 2022/8/24 16:57, Zhang Xiaoxu 写道:
Commit d5c7076b772a ("smb3: add smb3.1.1 to default dialect list")
extend the dialects from 3 to 4, but forget to decrease the extended
length when specific the dialect, then the message length is larger
than expected.
This maybe leak some info through network because not initialize the
message body.
After apply this patch, the VALIDATE_NEGOTIATE_INFO message length is
reduced from 28 bytes to 26 bytes.
Fixes: d5c7076b772a ("smb3: add smb3.1.1 to default dialect list")
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
fs/cifs/smb2pdu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1ecc2501c56f..3df7adc01fe5 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1162,9 +1162,9 @@ int smb3_validate_negotiate(const unsigned int
xid, struct cifs_tcon *tcon)
pneg_inbuf->Dialects[0] =
cpu_to_le16(server->vals->protocol_id);
pneg_inbuf->DialectCount = cpu_to_le16(1);
- /* structure is big enough for 3 dialects, sending only 1 */
+ /* structure is big enough for 4 dialects, sending only 1 */
inbuflen = sizeof(*pneg_inbuf) -
- sizeof(pneg_inbuf->Dialects[0]) * 2;
+ sizeof(pneg_inbuf->Dialects[0]) * 3;
}
rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
