4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
commit b9a74cde94957d82003fb9f7ab4777938ca851cd upstream.
If maxBuf is small but non-zero, it could result in a zero sized lock
element array which we would then try and access OOB.
Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/cifs/file.c | 8 ++++----
fs/cifs/smb2file.c | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1073,10 +1073,10 @@ cifs_push_mandatory_locks(struct cifsFil
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf) {
+ if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) {
free_xid(xid);
return -EINVAL;
}
@@ -1404,10 +1404,10 @@ cifs_unlock_range(struct cifsFileInfo *c
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf)
+ if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE)))
return -EINVAL;
max_num = (max_buf - sizeof(struct smb_hdr)) /
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -123,10 +123,10 @@ smb2_unlock_range(struct cifsFileInfo *c
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf)
+ if (max_buf < sizeof(struct smb2_lock_element))
return -EINVAL;
max_num = max_buf / sizeof(struct smb2_lock_element);
