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authorAndrew Tridgell <tridge@samba.org>2010-02-13 15:32:23 +1100
committerAndrew Tridgell <tridge@samba.org>2010-02-13 23:12:29 +1100
commitda86f08605f8ec9fa6d3e1c122ec47309deef994 (patch)
tree52e249167a67d50ce6c76d4d38128d4fd25461c5 /source4/librpc
parent3ae75a424890fdeddd12535c9330186ec2fcd899 (diff)
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s4-rpc: be more careful about DCERPC auth padding
Cope with a wider range of auth padding in dcerpc bind_ack and alter_context packets. We now use a helper function that calculates the right auth padding.
Diffstat (limited to 'source4/librpc')
-rw-r--r--source4/librpc/rpc/dcerpc.c75
-rw-r--r--source4/librpc/rpc/dcerpc_util.c60
2 files changed, 83 insertions, 52 deletions
diff --git a/source4/librpc/rpc/dcerpc.c b/source4/librpc/rpc/dcerpc.c
index c006693bab..e7b181c50b 100644
--- a/source4/librpc/rpc/dcerpc.c
+++ b/source4/librpc/rpc/dcerpc.c
@@ -223,11 +223,9 @@ static NTSTATUS ncacn_pull_request_auth(struct dcerpc_connection *c, TALLOC_CTX
DATA_BLOB *raw_packet,
struct ncacn_packet *pkt)
{
- struct ndr_pull *ndr;
NTSTATUS status;
struct dcerpc_auth auth;
- DATA_BLOB auth_blob;
- enum ndr_err_code ndr_err;
+ uint32_t auth_length;
if (!c->security_state.auth_info ||
!c->security_state.generic_state) {
@@ -254,33 +252,12 @@ static NTSTATUS ncacn_pull_request_auth(struct dcerpc_connection *c, TALLOC_CTX
return NT_STATUS_INVALID_LEVEL;
}
- auth_blob.length = 8 + pkt->auth_length;
-
- /* check for a valid length */
- if (pkt->u.response.stub_and_verifier.length < auth_blob.length) {
- return NT_STATUS_INFO_LENGTH_MISMATCH;
- }
-
- auth_blob.data =
- pkt->u.response.stub_and_verifier.data +
- pkt->u.response.stub_and_verifier.length - auth_blob.length;
- pkt->u.response.stub_and_verifier.length -= auth_blob.length;
+ status = dcerpc_pull_auth_trailer(pkt, mem_ctx,
+ &pkt->u.response.stub_and_verifier,
+ &auth, &auth_length, false);
+ NT_STATUS_NOT_OK_RETURN(status);
- /* pull the auth structure */
- ndr = ndr_pull_init_flags(c, &auth_blob, mem_ctx);
- if (!ndr) {
- return NT_STATUS_NO_MEMORY;
- }
-
- if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
- ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
- }
-
- ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
- if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
- return ndr_map_error2ntstatus(ndr_err);
- }
- status = NT_STATUS_OK;
+ pkt->u.response.stub_and_verifier.length -= auth_length;
/* check signature or unseal the packet */
switch (c->security_state.auth_info->auth_level) {
@@ -317,7 +294,7 @@ static NTSTATUS ncacn_pull_request_auth(struct dcerpc_connection *c, TALLOC_CTX
break;
}
- /* remove the indicated amount of paddiing */
+ /* remove the indicated amount of padding */
if (pkt->u.response.stub_and_verifier.length < auth.auth_pad_length) {
return NT_STATUS_INFO_LENGTH_MISMATCH;
}
@@ -600,7 +577,6 @@ static void dcerpc_recv_data(struct dcerpc_connection *conn, DATA_BLOB *blob, NT
dcerpc_request_recv_data(conn, blob, &pkt);
}
-
/*
Receive a bind reply from the transport
*/
@@ -643,17 +619,14 @@ static void dcerpc_bind_recv_handler(struct rpc_request *req,
}
/* the bind_ack might contain a reply set of credentials */
- if (conn->security_state.auth_info &&
- pkt->u.bind_ack.auth_info.length) {
- enum ndr_err_code ndr_err;
- ndr_err = ndr_pull_struct_blob(
- &pkt->u.bind_ack.auth_info, conn,
- NULL,
- conn->security_state.auth_info,
- (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
- if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
- c->status = ndr_map_error2ntstatus(ndr_err);
- if (!composite_is_ok(c)) return;
+ if (conn->security_state.auth_info && pkt->u.bind_ack.auth_info.length) {
+ NTSTATUS status;
+ uint32_t auth_length;
+ status = dcerpc_pull_auth_trailer(pkt, conn, &pkt->u.bind_ack.auth_info,
+ conn->security_state.auth_info, &auth_length, true);
+ if (!NT_STATUS_IS_OK(status)) {
+ composite_error(c, status);
+ return;
}
}
@@ -791,7 +764,6 @@ NTSTATUS dcerpc_auth3(struct dcerpc_pipe *p,
pkt.pfc_flags = DCERPC_PFC_FLAG_FIRST | DCERPC_PFC_FLAG_LAST;
pkt.call_id = next_call_id(p->conn);
pkt.auth_length = 0;
- pkt.u.auth3._pad = 0;
pkt.u.auth3.auth_info = data_blob(NULL, 0);
if (p->binding->flags & DCERPC_CONCURRENT_MULTIPLEX) {
@@ -1610,15 +1582,14 @@ static void dcerpc_alter_recv_handler(struct rpc_request *req,
/* the alter_resp might contain a reply set of credentials */
if (recv_pipe->conn->security_state.auth_info &&
pkt->u.alter_resp.auth_info.length) {
- enum ndr_err_code ndr_err;
- ndr_err = ndr_pull_struct_blob(
- &pkt->u.alter_resp.auth_info, recv_pipe,
- NULL,
- recv_pipe->conn->security_state.auth_info,
- (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
- if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
- c->status = ndr_map_error2ntstatus(ndr_err);
- if (!composite_is_ok(c)) return;
+ struct dcerpc_connection *conn = recv_pipe->conn;
+ NTSTATUS status;
+ uint32_t auth_length;
+ status = dcerpc_pull_auth_trailer(pkt, conn, &pkt->u.alter_resp.auth_info,
+ conn->security_state.auth_info, &auth_length, true);
+ if (!NT_STATUS_IS_OK(status)) {
+ composite_error(c, status);
+ return;
}
}
diff --git a/source4/librpc/rpc/dcerpc_util.c b/source4/librpc/rpc/dcerpc_util.c
index 86c91535e7..1985cb9e18 100644
--- a/source4/librpc/rpc/dcerpc_util.c
+++ b/source4/librpc/rpc/dcerpc_util.c
@@ -83,6 +83,10 @@ NTSTATUS ncacn_push_auth(DATA_BLOB *blob, TALLOC_CTX *mem_ctx,
}
if (auth_info) {
+ ndr_err = ndr_push_zero(ndr, auth_info->auth_pad_length);
+ if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+ return ndr_map_error2ntstatus(ndr_err);
+ }
ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, auth_info);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
return ndr_map_error2ntstatus(ndr_err);
@@ -750,3 +754,59 @@ _PUBLIC_ NTSTATUS dcerpc_secondary_context(struct dcerpc_pipe *p,
return NT_STATUS_OK;
}
+
+
+/*
+ pull an dcerpc_auth structure, taking account of any auth padding in
+ the blob at the end of the structure
+ */
+NTSTATUS dcerpc_pull_auth_trailer(struct ncacn_packet *pkt,
+ TALLOC_CTX *mem_ctx,
+ DATA_BLOB *pkt_auth_blob,
+ struct dcerpc_auth *auth,
+ uint32_t *auth_length,
+ bool check_pad)
+{
+ struct ndr_pull *ndr;
+ enum ndr_err_code ndr_err;
+ uint32_t pad;
+
+ pad = pkt_auth_blob->length - (DCERPC_AUTH_TRAILER_LENGTH + pkt->auth_length);
+ *auth_length = pkt_auth_blob->length - pad;
+
+ ndr = ndr_pull_init_blob(pkt_auth_blob, mem_ctx, NULL);
+ if (!ndr) {
+ return NT_STATUS_NO_MEMORY;
+ }
+
+ if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
+ ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
+ }
+
+ ndr_err = ndr_pull_advance(ndr, pad);
+ if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+ talloc_free(ndr);
+ return ndr_map_error2ntstatus(ndr_err);
+ }
+
+ ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, auth);
+ if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+ talloc_free(ndr);
+ return ndr_map_error2ntstatus(ndr_err);
+ }
+
+ if (check_pad && pad != auth->auth_pad_length) {
+ DEBUG(1,(__location__ ": WARNING: pad length mismatch. Calculated %u got %u\n",
+ (unsigned)pad, (unsigned)auth->auth_pad_length));
+ }
+
+ DEBUG(6,(__location__ ": auth_pad_length %u\n",
+ (unsigned)auth->auth_pad_length));
+
+ talloc_steal(mem_ctx, auth->credentials.data);
+ talloc_free(ndr);
+
+ return NT_STATUS_OK;
+}
+
+