The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 368ba06881c395f1c9a7ba22203cf8d78b4addc0 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023061233-omnivore-cardigan-93f8@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 368ba06881c395f1c9a7ba22203cf8d78b4addc0 Mon Sep 17 00:00:00 2001 From: Namjae Jeon <linkinjeon@xxxxxxxxxx> Date: Tue, 30 May 2023 23:10:31 +0900 Subject: [PATCH] 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@xxxxxxxxxxxxxxx Reported-by: Chih-Yen Chang <cc85nod@xxxxxxxxx> Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> 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;
