From: Namjae Jeon <linkinjeon@kernel.org> mainline inclusion from mainline-5.15-rc4 commit d72a9c158893d537d769a669a5837bc80b0f851c category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G CVE: NA Reference: https://git.kernel.org/torvalds/linux/c/d72a9c158893 ------------------------------- 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> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com> --- fs/ksmbd/smb2pdu.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index bb78a28af101..f124482fcccd 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -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; -- 2.31.1