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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 5/7] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value
Date: Fri, 24 Sep 2021 11:12:52 +0900	[thread overview]
Message-ID: <20210924021254.27096-6-linkinjeon@kernel.org> (raw)
In-Reply-To: <20210924021254.27096-1-linkinjeon@kernel.org>

This patch add MAX_STREAM_PROT_LEN macro and check if stream protocol
length exceeds maximum value. opencode pdu size check in
ksmbd_pdu_size_has_room().

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/connection.c | 10 ++++++----
 fs/ksmbd/smb_common.c |  6 ------
 fs/ksmbd/smb_common.h |  4 ++--
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c
index af086d35398a..48b18b4ec117 100644
--- a/fs/ksmbd/connection.c
+++ b/fs/ksmbd/connection.c
@@ -296,10 +296,12 @@ int ksmbd_conn_handler_loop(void *p)
 		pdu_size = get_rfc1002_len(hdr_buf);
 		ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);
 
-		/* make sure we have enough to get to SMB header end */
-		if (!ksmbd_pdu_size_has_room(pdu_size)) {
-			ksmbd_debug(CONN, "SMB request too short (%u bytes)\n",
-				    pdu_size);
+		/*
+		 * Check if pdu size is valid (min : smb header size,
+		 * max : 0x00FFFFFF).
+		 */
+		if (pdu_size < __SMB2_HEADER_STRUCTURE_SIZE ||
+		    pdu_size > MAX_STREAM_PROT_LEN) {
 			continue;
 		}
 
diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
index 5901b2884c60..20bd5b8e3c0a 100644
--- a/fs/ksmbd/smb_common.c
+++ b/fs/ksmbd/smb_common.c
@@ -21,7 +21,6 @@ static const char basechars[43] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_-!@#$%";
 #define MAGIC_CHAR '~'
 #define PERIOD '.'
 #define mangle(V) ((char)(basechars[(V) % MANGLE_BASE]))
-#define KSMBD_MIN_SUPPORTED_HEADER_SIZE	(sizeof(struct smb2_hdr))
 
 struct smb_protocol {
 	int		index;
@@ -272,11 +271,6 @@ int ksmbd_init_smb_server(struct ksmbd_work *work)
 	return 0;
 }
 
-bool ksmbd_pdu_size_has_room(unsigned int pdu)
-{
-	return (pdu >= KSMBD_MIN_SUPPORTED_HEADER_SIZE - 4);
-}
-
 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
 				      struct ksmbd_file *dir,
 				      struct ksmbd_dir_info *d_info,
diff --git a/fs/ksmbd/smb_common.h b/fs/ksmbd/smb_common.h
index 994abede27e9..6e79e7577f6b 100644
--- a/fs/ksmbd/smb_common.h
+++ b/fs/ksmbd/smb_common.h
@@ -48,6 +48,8 @@
 #define CIFS_DEFAULT_IOSIZE	(64 * 1024)
 #define MAX_CIFS_SMALL_BUFFER_SIZE 448 /* big enough for most */
 
+#define MAX_STREAM_PROT_LEN	0x00FFFFFF
+
 /* Responses when opening a file. */
 #define F_SUPERSEDED	0
 #define F_OPENED	1
@@ -493,8 +495,6 @@ int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count);
 
 int ksmbd_init_smb_server(struct ksmbd_work *work);
 
-bool ksmbd_pdu_size_has_room(unsigned int pdu);
-
 struct ksmbd_kstat;
 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work,
 				      int info_level,
-- 
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 ` Namjae Jeon [this message]
2021-09-25  8:41   ` [PATCH 5/7] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value 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 ` [PATCH 7/7] ksmbd: add validation in smb2 negotiate Namjae Jeon
2021-09-24  4:58   ` Namjae Jeon

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