From: Kuan-Ting Chen h3xrabbit@gmail.com
[ Upstream commit d738950f112c8f40f0515fe967db998e8235a175 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ksmbd/smb2pdu.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index e24fd10d85d3b..266430a2a0e07 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -1083,16 +1083,16 @@ 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) - 4; + 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) - 4; - 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;