From b96d0015840cbb5a22212cb70852fc8b99a67a81 Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Wed, 6 May 2015 15:33:23 -0700
Subject: [PATCH] Validate that headers contain legal bytes
---
include/grpc/grpc.h | 4 +++-
src/core/surface/call.c | 37 +++++++++++++++++++++++++++--------
src/core/transport/metadata.c | 16 +++++++++++++++
src/core/transport/metadata.h | 3 +++
4 files changed, 51 insertions(+), 9 deletions(-)
diff --git a/include/grpc/grpc.h b/include/grpc/grpc.h
index 9bb826f323..3348653956 100644
--- a/include/grpc/grpc.h
+++ b/include/grpc/grpc.h
@@ -140,7 +140,9 @@ typedef enum grpc_call_error {
/* there is already an outstanding read/write operation on the call */
GRPC_CALL_ERROR_TOO_MANY_OPERATIONS,
/* the flags value was illegal for this call */
- GRPC_CALL_ERROR_INVALID_FLAGS
+ GRPC_CALL_ERROR_INVALID_FLAGS,
+ /* invalid metadata was passed to this call */
+ GRPC_CALL_ERROR_INVALID_METADATA
} grpc_call_error;
/* Result of a grpc operation */
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 7ab9142947..9ee91785e8 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -739,14 +739,9 @@ static void call_on_done_recv(void *pc, int success) {
GRPC_TIMER_BEGIN(GRPC_PTAG_CALL_ON_DONE_RECV, 0);
}
-static grpc_mdelem_list chain_metadata_from_app(grpc_call *call, size_t count,
- grpc_metadata *metadata) {
+static int prepare_application_metadata(grpc_call *call, size_t count,
+ grpc_metadata *metadata) {
size_t i;
- grpc_mdelem_list out;
- if (count == 0) {
- out.head = out.tail = NULL;
- return out;
- }
for (i = 0; i < count; i++) {
grpc_metadata *md = &metadata[i];
grpc_metadata *next_md = (i == count - 1) ? NULL : &metadata[i + 1];
@@ -756,9 +751,27 @@ static grpc_mdelem_list chain_metadata_from_app(grpc_call *call, size_t count,
l->md = grpc_mdelem_from_string_and_buffer(call->metadata_context, md->key,
(const gpr_uint8 *)md->value,
md->value_length);
+ if (!grpc_mdstr_is_legal_header(l->md->key)) {
+ gpr_log(GPR_ERROR, "attempt to send invalid metadata key");
+ return 0;
+ } else if (!grpc_mdstr_is_bin_suffixed(l->md->key) &&
+ !grpc_mdstr_is_legal_header(l->md->value)) {
+ gpr_log(GPR_ERROR, "attempt to send invalid metadata value");
+ return 0;
+ }
l->next = next_md ? (grpc_linked_mdelem *)&next_md->internal_data : NULL;
l->prev = prev_md ? (grpc_linked_mdelem *)&prev_md->internal_data : NULL;
}
+ return 1;
+}
+
+static grpc_mdelem_list chain_metadata_from_app(grpc_call *call, size_t count,
+ grpc_metadata *metadata) {
+ grpc_mdelem_list out;
+ if (count == 0) {
+ out.head = out.tail = NULL;
+ return out;
+ }
out.head = (grpc_linked_mdelem *)&(metadata[0].internal_data);
out.tail = (grpc_linked_mdelem *)&(metadata[count - 1].internal_data);
return out;
@@ -954,8 +967,16 @@ static grpc_call_error start_ioreq(grpc_call *call, const grpc_ioreq *reqs,
} else if (call->request_set[op] == REQSET_DONE) {
return start_ioreq_error(call, have_ops, GRPC_CALL_ERROR_ALREADY_INVOKED);
}
- have_ops |= 1u << op;
data = reqs[i].data;
+ if (op == GRPC_IOREQ_SEND_INITIAL_METADATA ||
+ op == GRPC_IOREQ_SEND_TRAILING_METADATA) {
+ if (!prepare_application_metadata(call, data.send_metadata.count,
+ data.send_metadata.metadata)) {
+ return start_ioreq_error(call, have_ops,
+ GRPC_CALL_ERROR_INVALID_METADATA);
+ }
+ }
+ have_ops |= 1u << op;
call->request_data[op] = data;
call->request_set[op] = set;
diff --git a/src/core/transport/metadata.c b/src/core/transport/metadata.c
index 74e94b2c24..c80d67823f 100644
--- a/src/core/transport/metadata.c
+++ b/src/core/transport/metadata.c
@@ -569,3 +569,19 @@ void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx, grpc_mdelem *gmd) {
}
void grpc_mdctx_unlock(grpc_mdctx *ctx) { unlock(ctx); }
+
+int grpc_mdstr_is_legal_header(grpc_mdstr *s) {
+ /* TODO(ctiller): consider caching this, or computing it on construction */
+ const gpr_uint8 *p = GPR_SLICE_START_PTR(s->slice);
+ const gpr_uint8 *e = GPR_SLICE_END_PTR(s->slice);
+ for (; p != e; p++) {
+ if (*p < 32 || *p > 126) return 0;
+ }
+ return 1;
+}
+
+int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s) {
+ /* TODO(ctiller): consider caching this */
+ return grpc_is_binary_header((const char *)GPR_SLICE_START_PTR(s->slice),
+ GPR_SLICE_LENGTH(s->slice));
+}
diff --git a/src/core/transport/metadata.h b/src/core/transport/metadata.h
index 21b8ae2b78..e7508718f5 100644
--- a/src/core/transport/metadata.h
+++ b/src/core/transport/metadata.h
@@ -135,6 +135,9 @@ void grpc_mdelem_unref(grpc_mdelem *md);
Does not promise that the returned string has no embedded nulls however. */
const char *grpc_mdstr_as_c_string(grpc_mdstr *s);
+int grpc_mdstr_is_legal_header(grpc_mdstr *s);
+int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
+
/* Batch mode metadata functions.
These API's have equivalents above, but allow taking the mdctx just once,
performing a bunch of work, and then leaving the mdctx. */
--
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