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Sat, 25 Sep 2021 02:24:01 -0700 (PDT) In-Reply-To: References: <20210924021254.27096-1-linkinjeon@kernel.org> <20210924021254.27096-6-linkinjeon@kernel.org> From: Namjae Jeon Date: Sat, 25 Sep 2021 18:24:01 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 5/7] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value To: Hyunchul Lee Cc: linux-cifs , Tom Talpey , Ronnie Sahlberg , =?UTF-8?B?UmFscGggQsO2aG1l?= , Steve French , Sergey Senozhatsky Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org 2021-09-25 17:41 GMT+09:00, Hyunchul Lee : > 2021=EB=85=84 9=EC=9B=94 24=EC=9D=BC (=EA=B8=88) =EC=98=A4=EC=A0=84 11:13= , Namjae Jeon =EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1: >> >> 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 >> Cc: Ronnie Sahlberg >> Cc: Ralph B=C3=B6hme >> Cc: Steve French >> Cc: Hyunchul Lee >> Cc: Sergey Senozhatsky >> Signed-off-by: Namjae Jeon >> --- >> 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 =3D 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] =3D >> "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 >=3D 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 > > Do we need to append "SMB" to this macro name? I named it with the name defined in specification. That is, no problem. > Looks good to me. > Acked-by: Hyunchul Lee Thanks for your review! > > >> + >> /* 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 >> > > > -- > Thanks, > Hyunchul >