[PATCH v6 01/14] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value

Ralph Boehme
2021-10-02T13:25:15Z

From: Namjae Jeon <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: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
fs/ksmbd/connection.c | 9 +++++----
fs/ksmbd/smb_common.c | 6 ------
fs/ksmbd/smb_common.h | 4 ++--
3 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c
index af086d35398a..e50353c50661 100644
--- a/fs/ksmbd/connection.c
+++ b/fs/ksmbd/connection.c
@@ -296,10 +296,11 @@ 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 > MAX_STREAM_PROT_LEN) {
continue;
}

diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
index db8042a173d0..b6c4c7e960fa 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;
@@ -294,11 +293,6 @@ 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,
--
2.31.1