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@vger.kernel.org.

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 d738950f112c8f40f0515fe967db998e8235a175 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023060707-profanity-submitter-e855@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d738950f112c8f40f0515fe967db998e8235a175 Mon Sep 17 00:00:00 2001 From: Kuan-Ting Chen h3xrabbit@gmail.com Date: Fri, 19 May 2023 22:59:28 +0900 Subject: [PATCH] ksmbd: fix slab-out-of-bounds read in smb2_handle_negotiate

Check request_buf length first to avoid out-of-bounds read by req->DialectCount.

[ 3350.990282] BUG: KASAN: slab-out-of-bounds in smb2_handle_negotiate+0x35d7/0x3e60 [ 3350.990282] Read of size 2 at addr ffff88810ad61346 by task kworker/5:0/276 [ 3351.000406] Workqueue: ksmbd-io handle_ksmbd_work [ 3351.003499] Call Trace: [ 3351.006473] <TASK> [ 3351.006473] dump_stack_lvl+0x8d/0xe0 [ 3351.006473] print_report+0xcc/0x620 [ 3351.006473] kasan_report+0x92/0xc0 [ 3351.006473] smb2_handle_negotiate+0x35d7/0x3e60 [ 3351.014760] ksmbd_smb_negotiate_common+0x7a7/0xf00 [ 3351.014760] handle_ksmbd_work+0x3f7/0x12d0 [ 3351.014760] process_one_work+0xa85/0x1780

Cc: stable@vger.kernel.org Signed-off-by: Kuan-Ting Chen h3xrabbit@gmail.com Acked-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index bec885c007ce..83c668243c95 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -1053,16 +1053,16 @@ int smb2_handle_negotiate(struct ksmbd_work *work) return rc; }

- if (req->DialectCount == 0) { - pr_err("malformed packet\n"); + smb2_buf_len = get_rfc1002_len(work->request_buf); + smb2_neg_size = offsetof(struct smb2_negotiate_req, Dialects); + if (smb2_neg_size > smb2_buf_len) { rsp->hdr.Status = STATUS_INVALID_PARAMETER; rc = -EINVAL; goto err_out; }

- smb2_buf_len = get_rfc1002_len(work->request_buf); - smb2_neg_size = offsetof(struct smb2_negotiate_req, Dialects); - if (smb2_neg_size > smb2_buf_len) { + if (req->DialectCount == 0) { + pr_err("malformed packet\n"); rsp->hdr.Status = STATUS_INVALID_PARAMETER; rc = -EINVAL; goto err_out;