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From: Namjae Jeon <linkinjeon@kernel.org>
To: linux-cifs@vger.kernel.org
Cc: "Namjae Jeon" <linkinjeon@kernel.org>,
	"Tom Talpey" <tom@talpey.com>,
	"Ronnie Sahlberg" <ronniesahlberg@gmail.com>,
	"Ralph Böhme" <slow@samba.org>,
	"Steve French" <smfrench@gmail.com>,
	"Hyunchul Lee" <hyc.lee@gmail.com>,
	"Sergey Senozhatsky" <senozhatsky@chromium.org>
Subject: [PATCH 7/7] ksmbd: add validation in smb2 negotiate
Date: Fri, 24 Sep 2021 11:12:54 +0900	[thread overview]
Message-ID: <20210924021254.27096-8-linkinjeon@kernel.org> (raw)
In-Reply-To: <20210924021254.27096-1-linkinjeon@kernel.org>

This patch add validation to check request buffer check in smb2
negotiate.

Cc: Tom Talpey <tom@talpey.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Ralph Böhme <slow@samba.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Hyunchul Lee <hyc.lee@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/ksmbd/smb2pdu.c    | 39 +++++++++++++++++++++++++++++++++++++++
 fs/ksmbd/smb_common.c | 22 ++++++++++++++++++++--
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 4f7b5e18a7b9..9f45779c5f95 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -1081,6 +1081,7 @@ int smb2_handle_negotiate(struct ksmbd_work *work)
 	struct smb2_negotiate_req *req = work->request_buf;
 	struct smb2_negotiate_rsp *rsp = work->response_buf;
 	int rc = 0;
+	unsigned int smb2_buf_len, smb2_neg_size;
 	__le32 status;
 
 	ksmbd_debug(SMB, "Received negotiate request\n");
@@ -1098,6 +1099,44 @@ int smb2_handle_negotiate(struct ksmbd_work *work)
 		goto err_out;
 	}
 
+	smb2_buf_len = get_rfc1002_len(work->request_buf);
+	smb2_neg_size = offsetof(struct smb2_negotiate_req, Dialects) - 4;
+	if (conn->dialect == SMB311_PROT_ID) {
+		unsigned int nego_ctxt_off = le32_to_cpu(req->NegotiateContextOffset);
+
+		if (smb2_buf_len < nego_ctxt_off) {
+			rsp->hdr.Status = STATUS_INVALID_PARAMETER;
+			rc = -EINVAL;
+			goto err_out;
+		}
+
+		if (smb2_neg_size > nego_ctxt_off) {
+			rsp->hdr.Status = STATUS_INVALID_PARAMETER;
+			rc = -EINVAL;
+			goto err_out;
+		}
+
+		if (smb2_neg_size + le16_to_cpu(req->DialectCount) * sizeof(__le16) >
+		    nego_ctxt_off) {
+			rsp->hdr.Status = STATUS_INVALID_PARAMETER;
+			rc = -EINVAL;
+			goto err_out;
+		}
+	} else {
+		if (smb2_neg_size > smb2_buf_len) {
+			rsp->hdr.Status = STATUS_INVALID_PARAMETER;
+			rc = -EINVAL;
+			goto err_out;
+		}
+
+		if (smb2_neg_size + le16_to_cpu(req->DialectCount) * sizeof(__le16) >
+		    smb2_buf_len) {
+			rsp->hdr.Status = STATUS_INVALID_PARAMETER;
+			rc = -EINVAL;
+			goto err_out;
+		}
+	}
+
 	conn->cli_cap = le32_to_cpu(req->Capabilities);
 	switch (conn->dialect) {
 	case SMB311_PROT_ID:
diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
index 20bd5b8e3c0a..85937d497dcb 100644
--- a/fs/ksmbd/smb_common.c
+++ b/fs/ksmbd/smb_common.c
@@ -234,13 +234,22 @@ int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
 
 static int ksmbd_negotiate_smb_dialect(void *buf)
 {
-	__le32 proto;
+	int smb_buf_length = get_rfc1002_len(buf);
+	__le32 proto = ((struct smb2_hdr *)buf)->ProtocolId;
 
-	proto = ((struct smb2_hdr *)buf)->ProtocolId;
 	if (proto == SMB2_PROTO_NUMBER) {
 		struct smb2_negotiate_req *req;
+		int smb2_neg_size =
+			offsetof(struct smb2_negotiate_req, Dialects) - 4;
 
 		req = (struct smb2_negotiate_req *)buf;
+		if (smb2_neg_size > smb_buf_length)
+			goto err_out;
+
+		if (smb2_neg_size + le16_to_cpu(req->DialectCount) * sizeof(__le16) >
+		    smb_buf_length)
+			goto err_out;
+
 		return ksmbd_lookup_dialect_by_id(req->Dialects,
 						  req->DialectCount);
 	}
@@ -250,10 +259,19 @@ static int ksmbd_negotiate_smb_dialect(void *buf)
 		struct smb_negotiate_req *req;
 
 		req = (struct smb_negotiate_req *)buf;
+		if (le16_to_cpu(req->ByteCount) < 2)
+			goto err_out;
+
+		if (offsetof(struct smb_negotiate_req, DialectsArray) - 4 +
+			le16_to_cpu(req->ByteCount) > smb_buf_length) {
+			goto err_out;
+		}
+
 		return ksmbd_lookup_dialect_by_name(req->DialectsArray,
 						    req->ByteCount);
 	}
 
+err_out:
 	return BAD_PROT_ID;
 }
 
-- 
2.25.1


  parent reply	other threads:[~2021-09-24  2:13 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-24  2:12 [PATCH 0/7] a bunch of patches that have not yet been reviewed Namjae Jeon
2021-09-24  2:12 ` [PATCH 1/7] ksmbd: add validation in smb2_ioctl Namjae Jeon
2021-09-25 10:16   ` Hyunchul Lee
2021-09-25 10:44     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 2/7] ksmbd: add request buffer validation in smb2_set_info Namjae Jeon
2021-09-25  8:13   ` Hyunchul Lee
2021-09-25  9:19     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 3/7] ksmbd: remove RFC1002 check in smb2 request Namjae Jeon
2021-09-25  8:18   ` Hyunchul Lee
2021-09-24  2:12 ` [PATCH 4/7] ksmbd: check strictly data area in ksmbd_smb2_check_message() Namjae Jeon
2021-09-25 10:27   ` Hyunchul Lee
2021-09-25 10:46     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 5/7] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value Namjae Jeon
2021-09-25  8:41   ` Hyunchul Lee
2021-09-25  9:24     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 6/7] ksmbd: fix invalid request buffer access in compound Namjae Jeon
2021-09-25  9:41   ` Hyunchul Lee
2021-09-24  2:12 ` Namjae Jeon [this message]
2021-09-24  4:58   ` [PATCH 7/7] ksmbd: add validation in smb2 negotiate Namjae Jeon

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