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ksmbd: fix invalid request buffer access in compound

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Ronnie reported invalid request buffer access in chained command when
inserting garbage value to NextCommand of compound request.
This patch add validation check to avoid this issue.

Cc: Tom Talpey <tom@talpey.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Ralph Böhme <slow@samba.org>
Tested-by: Steve French <smfrench@gmail.com>
Reviewed-by: Steve French <smfrench@gmail.com>
Acked-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Namjae Jeon 2021-09-24 09:24:08 +09:00 committed by Steve French
parent 18d46769d5
commit d72a9c1588
1 changed files with 11 additions and 2 deletions
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13
fs/ksmbd/smb2pdu.c
View File

@ -459,13 +459,22 @@ static void init_chained_smb2_rsp(struct ksmbd_work *work)
bool is_chained_smb2_message(struct ksmbd_work *work)
{
struct smb2_hdr *hdr = work->request_buf;
unsigned int len;
unsigned int len, next_cmd;
if (hdr->ProtocolId != SMB2_PROTO_NUMBER)
return false;
hdr = ksmbd_req_buf_next(work);
if (le32_to_cpu(hdr->NextCommand) > 0) {
next_cmd = le32_to_cpu(hdr->NextCommand);
if (next_cmd > 0) {
if ((u64)work->next_smb2_rcv_hdr_off + next_cmd +
__SMB2_HEADER_STRUCTURE_SIZE >
get_rfc1002_len(work->request_buf)) {
pr_err("next command(%u) offset exceeds smb msg size\n",
next_cmd);
return false;
}
ksmbd_debug(SMB, "got SMB2 chained command\n");
init_chained_smb2_rsp(work);
return true;