From 442ff9ebeb0129e90483356f3d79c732e632a7a6 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Wed, 29 Sep 2021 15:44:32 +0900 Subject: ksmbd: add validation in smb2 negotiate This patch add validation to check request buffer check in smb2 negotiate and fix null pointer deferencing oops in smb3_preauth_hash_rsp() that found from manual test. Cc: Tom Talpey Cc: Ronnie Sahlberg Cc: Ralph Böhme Cc: Hyunchul Lee Cc: Sergey Senozhatsky Reviewed-by: Ralph Boehme Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/ksmbd/smb2pdu.c | 42 +++++++++++++++++++++++++++++++++++++++++- fs/ksmbd/smb_common.c | 32 +++++++++++++++++++++++++++----- 2 files changed, 68 insertions(+), 6 deletions(-) (limited to 'fs') diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index 0d915554f532..40882fd47feb 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -1067,6 +1067,7 @@ 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"); @@ -1084,6 +1085,44 @@ 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 (smb2_neg_size > smb2_buf_len) { + rsp->hdr.Status = STATUS_INVALID_PARAMETER; + rc = -EINVAL; + goto err_out; + } + + 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 + 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: @@ -8244,7 +8283,8 @@ void smb3_preauth_hash_rsp(struct ksmbd_work *work) WORK_BUFFERS(work, req, rsp); - if (le16_to_cpu(req->Command) == SMB2_NEGOTIATE_HE) + if (le16_to_cpu(req->Command) == SMB2_NEGOTIATE_HE && + conn->preauth_info) ksmbd_gen_preauth_integrity_hash(conn, (char *)rsp, conn->preauth_info->Preauth_HashValue); diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c index 5901b2884c60..db8042a173d0 100644 --- a/fs/ksmbd/smb_common.c +++ b/fs/ksmbd/smb_common.c @@ -169,10 +169,12 @@ static bool supported_protocol(int idx) idx <= server_conf.max_protocol); } -static char *next_dialect(char *dialect, int *next_off) +static char *next_dialect(char *dialect, int *next_off, int bcount) { dialect = dialect + *next_off; - *next_off = strlen(dialect); + *next_off = strnlen(dialect, bcount); + if (dialect[*next_off] != '\0') + return NULL; return dialect; } @@ -187,7 +189,9 @@ static int ksmbd_lookup_dialect_by_name(char *cli_dialects, __le16 byte_count) dialect = cli_dialects; bcount = le16_to_cpu(byte_count); do { - dialect = next_dialect(dialect, &next); + dialect = next_dialect(dialect, &next, bcount); + if (!dialect) + break; ksmbd_debug(SMB, "client requested dialect %s\n", dialect); if (!strcmp(dialect, smb1_protos[i].name)) { @@ -235,13 +239,22 @@ 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); } @@ -251,10 +264,19 @@ 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; } -- cgit v1.2.3