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Sat, 02 Oct 2021 13:12:22 +0000 From: Ralph Boehme To: linux-cifs@vger.kernel.org Cc: Ralph Boehme Subject: [PATCH v6 06/14] ksmbd: check buffer is big enough to access the ProtocolId field Date: Sat, 2 Oct 2021 15:12:04 +0200 Message-Id: <20211002131212.130629-7-slow@samba.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211002131212.130629-1-slow@samba.org> References: <20211002131212.130629-1-slow@samba.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Signed-off-by: Ralph Boehme --- fs/ksmbd/smb2misc.c | 25 +++++++++++++++++++++++++ fs/ksmbd/smb2pdu.h | 1 + fs/ksmbd/smb_common.c | 8 ++++++++ 3 files changed, 34 insertions(+) diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c index 9edd9c161b27..c1f0f10ca9f9 100644 --- a/fs/ksmbd/smb2misc.c +++ b/fs/ksmbd/smb2misc.c @@ -432,3 +432,28 @@ int smb2_negotiate_request(struct ksmbd_work *work) { return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE); } + +/** + * ksmbd_smb2_cur_pdu_buflen() - Get len of current SMB2 PDU buffer + * This returns the lenght including any possible padding. + * @work: smb work containing request buffer + */ +unsigned int ksmbd_smb2_cur_pdu_buflen(struct ksmbd_work *work) +{ + struct smb2_hdr *hdr = ksmbd_req_buf_next(work); + unsigned int buf_len; + unsigned int pdu_len; + + if (hdr->NextCommand != 0) { + /* + * hdr->NextCommand has already been validated by + * init_chained_smb2_rsp(). + */ + return __le32_to_cpu(hdr->NextCommand); + } + + buf_len = get_rfc1002_len(work->request_buf); + pdu_len = buf_len - work->next_smb2_rcv_hdr_off; + return pdu_len; +} + diff --git a/fs/ksmbd/smb2pdu.h b/fs/ksmbd/smb2pdu.h index a6dec5ec6a54..c5fa8256b0bb 100644 --- a/fs/ksmbd/smb2pdu.h +++ b/fs/ksmbd/smb2pdu.h @@ -1680,6 +1680,7 @@ int smb2_set_rsp_credits(struct ksmbd_work *work); /* smb2 misc functions */ int ksmbd_smb2_check_message(struct ksmbd_work *work); +unsigned int ksmbd_smb2_cur_pdu_buflen(struct ksmbd_work *work); /* smb2 command handlers */ int smb2_handle_negotiate(struct ksmbd_work *work); diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c index e1e5a071678e..0dc70ed2a5be 100644 --- a/fs/ksmbd/smb_common.c +++ b/fs/ksmbd/smb_common.c @@ -133,8 +133,16 @@ int ksmbd_lookup_protocol_idx(char *str) int ksmbd_verify_smb_message(struct ksmbd_work *work) { struct smb2_hdr *smb2_hdr = ksmbd_req_buf_next(work); + unsigned int buflen = ksmbd_smb2_cur_pdu_buflen(work); struct smb_hdr *hdr; + /* + * ksmbd_smb2_check_message() will verify all SMB2 PDU buffer sizes, + * here we just check we can access the ProtocolId field in the header. + */ + if (buflen < sizeof(smb2_hdr->ProtocolId)) + return -EINVAL; + if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER) return ksmbd_smb2_check_message(work);