fix bug in resolving templates if strings contain escaped quotes (#16)

* fix bug in resolving templates if strings contain escaped quotes
awslabs · Oct 27, 2022 · 662905e · 662905e
1 parent 3b2cbbb
commit 662905e
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Showing 4 changed files with 69 additions and 15 deletions.
diff --git a/include/aws/sdkutils/private/endpoints_util.h b/include/aws/sdkutils/private/endpoints_util.h
@@ -19,20 +19,20 @@ struct aws_owning_cursor {
 };
 
 /* Clones string and wraps it in owning cursor. */
-struct aws_owning_cursor aws_endpoints_owning_cursor_create(
+AWS_SDKUTILS_API struct aws_owning_cursor aws_endpoints_owning_cursor_create(
     struct aws_allocator *allocator,
     const struct aws_string *str);
 /* Creates new cursor that takes ownership of created string. */
-struct aws_owning_cursor aws_endpoints_owning_cursor_from_string(struct aws_string *str);
+AWS_SDKUTILS_API struct aws_owning_cursor aws_endpoints_owning_cursor_from_string(struct aws_string *str);
 /* Clones memory pointer to by cursor and wraps in owning cursor */
-struct aws_owning_cursor aws_endpoints_owning_cursor_from_cursor(
+AWS_SDKUTILS_API struct aws_owning_cursor aws_endpoints_owning_cursor_from_cursor(
     struct aws_allocator *allocator,
     const struct aws_byte_cursor cur);
 /* Creates owning cursor with memory pointer set to NULL */
-struct aws_owning_cursor aws_endpoints_non_owning_cursor_create(struct aws_byte_cursor cur);
+AWS_SDKUTILS_API struct aws_owning_cursor aws_endpoints_non_owning_cursor_create(struct aws_byte_cursor cur);
 
 /* Cleans up memory associated with the cursor */
-void aws_owning_cursor_clean_up(struct aws_owning_cursor *cursor);
+AWS_SDKUTILS_API void aws_owning_cursor_clean_up(struct aws_owning_cursor *cursor);
 
 /*
  * Determine whether host cursor is IPv4 string.

diff --git a/source/endpoints_util.c b/source/endpoints_util.c
@@ -333,10 +333,18 @@ static bool s_split_on_first_delim(
 static int s_buf_append_and_update_quote_count(
     struct aws_byte_buf *buf,
     struct aws_byte_cursor to_append,
-    size_t *quote_count) {
-    for (size_t idx = 0; idx < to_append.len; ++idx) {
-        if (to_append.ptr[idx] == '"' && !(idx > 0 && to_append.ptr[idx - 1] == '\\')) {
-            ++*quote_count;
+    size_t *quote_count,
+    bool is_json) {
+
+    /* Dont count quotes if its not json. escaped quotes will be replaced with
+    regular quotes when ruleset json is parsed, which will lead to incorrect
+    results for when templates should be resolved in regular strings.
+    Note: in json blobs escaped quotes are preserved and bellow approach works. */
+    if (is_json) {
+        for (size_t idx = 0; idx < to_append.len; ++idx) {
+            if (to_append.ptr[idx] == '"' && !(idx > 0 && to_append.ptr[idx - 1] == '\\')) {
+                ++*quote_count;
+            }
         }
     }
     return aws_byte_buf_append_dynamic(buf, &to_append);
@@ -354,12 +362,14 @@ static struct aws_byte_cursor escaped_opening_curly = AWS_BYTE_CUR_INIT_FROM_STR
 int s_append_template_prefix_to_buffer(
     struct aws_byte_buf *out_buf,
     struct aws_byte_cursor prefix,
-    size_t *quote_count) {
+    size_t *quote_count,
+    bool is_json) {
+
     struct aws_byte_cursor split = {0};
     struct aws_byte_cursor rest = {0};
 
     while (s_split_on_first_delim(prefix, '}', &split, &rest)) {
-        if (s_buf_append_and_update_quote_count(out_buf, split, quote_count)) {
+        if (s_buf_append_and_update_quote_count(out_buf, split, quote_count, is_json)) {
             AWS_LOGF_ERROR(AWS_LS_SDKUTILS_ENDPOINTS_GENERAL, "Failed to append to resolved template buffer.");
             goto on_error;
         }
@@ -388,7 +398,7 @@ int s_append_template_prefix_to_buffer(
         prefix = rest;
     }
 
-    if (s_buf_append_and_update_quote_count(out_buf, split, quote_count)) {
+    if (s_buf_append_and_update_quote_count(out_buf, split, quote_count, is_json)) {
         AWS_LOGF_ERROR(AWS_LS_SDKUTILS_ENDPOINTS_GENERAL, "Failed to append to resolved template buffer.");
         goto on_error;
     }
@@ -419,7 +429,7 @@ int aws_byte_buf_init_from_resolved_templated_string(
     struct aws_byte_cursor split = {0};
     struct aws_byte_cursor rest = {0};
     while (s_split_on_first_delim(string, '{', &split, &rest)) {
-        if (s_append_template_prefix_to_buffer(out_buf, split, &quote_count)) {
+        if (s_append_template_prefix_to_buffer(out_buf, split, &quote_count, is_json)) {
             AWS_LOGF_ERROR(
                 AWS_LS_SDKUTILS_ENDPOINTS_GENERAL, "Failed to append to buffer while evaluating templated sting.");
             goto on_error;
@@ -460,15 +470,15 @@ int aws_byte_buf_init_from_resolved_templated_string(
             goto on_error;
         }
 
-        if (s_buf_append_and_update_quote_count(out_buf, resolved_template.cur, &quote_count)) {
+        if (s_buf_append_and_update_quote_count(out_buf, resolved_template.cur, &quote_count, is_json)) {
             AWS_LOGF_ERROR(AWS_LS_SDKUTILS_ENDPOINTS_GENERAL, "Failed to append resolved value.");
             goto on_error;
         }
 
         aws_owning_cursor_clean_up(&resolved_template);
     }
 
-    if (s_buf_append_and_update_quote_count(out_buf, split, &quote_count)) {
+    if (s_buf_append_and_update_quote_count(out_buf, split, &quote_count, is_json)) {
         AWS_LOGF_ERROR(AWS_LS_SDKUTILS_ENDPOINTS_GENERAL, "Failed to append to resolved template buffer.");
         goto on_error;
     }

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
@@ -87,6 +87,7 @@ add_test_case(endpoints_eval_util_is_ipv4)
 add_test_case(endpoints_eval_util_is_ipv6)
 add_test_case(endpoints_map_region_to_partition)
 add_test_case(endpoints_uri_normalize_path)
+add_test_case(endpoints_byte_buf_init_from_resolved_templated_string)
 
 set(TEST_BINARY_NAME ${PROJECT_NAME}-tests)
 generate_test_driver(${TEST_BINARY_NAME})

diff --git a/tests/endpoints_util_tests.c b/tests/endpoints_util_tests.c
@@ -136,3 +136,46 @@ static int s_test_uri_normalize_path(struct aws_allocator *allocator, void *ctx)
 
     return AWS_OP_SUCCESS;
 }
+
+int s_resolve_cb(struct aws_byte_cursor template, void *user_data, struct aws_owning_cursor *out_resolved) {
+    (void)template;
+    (void)user_data;
+    *out_resolved = aws_endpoints_non_owning_cursor_create(aws_byte_cursor_from_c_str("test"));
+    return AWS_OP_SUCCESS;
+}
+
+AWS_TEST_CASE(
+    endpoints_byte_buf_init_from_resolved_templated_string,
+    s_test_byte_buf_init_from_resolved_templated_string)
+static int s_test_byte_buf_init_from_resolved_templated_string(struct aws_allocator *allocator, void *ctx) {
+    (void)ctx;
+
+    struct aws_byte_buf buf;
+
+    ASSERT_SUCCESS(aws_byte_buf_init_from_resolved_templated_string(
+        allocator, &buf, aws_byte_cursor_from_c_str("{e} a {b}{c} a {d}"), s_resolve_cb, NULL, false));
+    ASSERT_CURSOR_VALUE_CSTRING_EQUALS(aws_byte_cursor_from_buf(&buf), "test a testtest a test");
+    aws_byte_buf_clean_up(&buf);
+
+    ASSERT_SUCCESS(aws_byte_buf_init_from_resolved_templated_string(
+        allocator,
+        &buf,
+        aws_byte_cursor_from_c_str("{ \"a\": \"{b} {d} \", \"c\": \" {e} \"}"),
+        s_resolve_cb,
+        NULL,
+        true));
+    ASSERT_CURSOR_VALUE_CSTRING_EQUALS(aws_byte_cursor_from_buf(&buf), "{ \"a\": \"test test \", \"c\": \" test \"}");
+    aws_byte_buf_clean_up(&buf);
+
+    ASSERT_SUCCESS(aws_byte_buf_init_from_resolved_templated_string(
+        allocator, &buf, aws_byte_cursor_from_c_str("a \" {b} \" a"), s_resolve_cb, NULL, false));
+    ASSERT_CURSOR_VALUE_CSTRING_EQUALS(aws_byte_cursor_from_buf(&buf), "a \" test \" a");
+    aws_byte_buf_clean_up(&buf);
+
+    ASSERT_SUCCESS(aws_byte_buf_init_from_resolved_templated_string(
+        allocator, &buf, aws_byte_cursor_from_c_str("{ \"a\": \"a \\\" {b} \\\" a\" }"), s_resolve_cb, NULL, true));
+    ASSERT_CURSOR_VALUE_CSTRING_EQUALS(aws_byte_cursor_from_buf(&buf), "{ \"a\": \"a \\\" test \\\" a\" }");
+    aws_byte_buf_clean_up(&buf);
+
+    return AWS_OP_SUCCESS;
+}