diff options
| author | Namjae Jeon <linkinjeon@kernel.org> | 2023-05-30 23:10:31 +0900 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2023-06-02 12:30:57 -0500 |
| commit | 368ba06881c395f1c9a7ba22203cf8d78b4addc0 (patch) | |
| tree | d345ce739bf0a5db36471ed9eee5f3a43aaadfd3 /fs/smb | |
| parent | 25933573ef48f3586f559c2cac6c436c62dcf63f (diff) | |
ksmbd: check the validation of pdu_size in ksmbd_conn_handler_loop
The length field of netbios header must be greater than the SMB header
sizes(smb1 or smb2 header), otherwise the packet is an invalid SMB packet.
If `pdu_size` is 0, ksmbd allocates a 4 bytes chunk to `conn->request_buf`.
In the function `get_smb2_cmd_val` ksmbd will read cmd from
`rcv_hdr->Command`, which is `conn->request_buf + 12`, causing the KASAN
detector to print the following error message:
[ 7.205018] BUG: KASAN: slab-out-of-bounds in get_smb2_cmd_val+0x45/0x60
[ 7.205423] Read of size 2 at addr ffff8880062d8b50 by task ksmbd:42632/248
...
[ 7.207125] <TASK>
[ 7.209191] get_smb2_cmd_val+0x45/0x60
[ 7.209426] ksmbd_conn_enqueue_request+0x3a/0x100
[ 7.209712] ksmbd_server_process_request+0x72/0x160
[ 7.210295] ksmbd_conn_handler_loop+0x30c/0x550
[ 7.212280] kthread+0x160/0x190
[ 7.212762] ret_from_fork+0x1f/0x30
[ 7.212981] </TASK>
Cc: stable@vger.kernel.org
Reported-by: Chih-Yen Chang <cc85nod@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/smb')
| -rw-r--r-- | fs/smb/server/connection.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index 4882a812ea86..e11d4a1e63d7 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -294,6 +294,9 @@ bool ksmbd_conn_alive(struct ksmbd_conn *conn) return true; } +#define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr)) +#define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4) + /** * ksmbd_conn_handler_loop() - session thread to listen on new smb requests * @p: connection instance @@ -350,6 +353,9 @@ int ksmbd_conn_handler_loop(void *p) if (pdu_size > MAX_STREAM_PROT_LEN) break; + if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE) + break; + /* 4 for rfc1002 length field */ /* 1 for implied bcc[0] */ size = pdu_size + 4 + 1; @@ -377,6 +383,12 @@ int ksmbd_conn_handler_loop(void *p) continue; } + if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId == + SMB2_PROTO_NUMBER) { + if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE) + break; + } + if (!default_conn_ops.process_fn) { pr_err("No connection request callback\n"); break; |