MONGOCRYPT-865 check returns of realloc (mongodb#1122)

Author: kevinAlbs

kms-message/src/kms_request_str.c

@@ -143,6 +143,7 @@ kms_request_str_reserve (kms_request_str_t *str, size_t size)
 
       str->size = next_size;
       str->str = realloc (str->str, next_size);
+      KMS_ASSERT(str->str);
    }
 
    return str->str != NULL;

kms-message/test/test_kms_request.c

@@ -114,6 +114,7 @@ realloc_buffer (char **buffer, size_t *n, size_t len)
 
    } else {
       *buffer = realloc (*buffer, len);
+      KMS_ASSERT(*buffer);
    }
 
    *n = len;

src/mc-mlib/str.h

@@ -247,6 +247,7 @@ static inline void mstrm_resize(mstr_mut *s, size_t new_len) {
         // enough to link it to the free() in mstr_free()
         assert(new_len < SIZE_MAX);
         s->raw.data = (char *)realloc((char *)s->raw.data, new_len + 1);
+        assert(s->raw.data);
 #endif
         s->raw.len = new_len;
         assert(new_len >= old_len);

test/test-mc-text-search-str-encode.c

@@ -422,6 +422,7 @@ static char *build_random_string_to_fold(uint32_t folded_len, uint32_t unfolded_
     uint32_t len = (uint32_t)(ptr - str);
     // ptr points to the final null character, include that in the final string.
     str = realloc(str, len + 1);
+    ASSERT(str);
 
     // Make sure we did everything right.
     ASSERT_CMPUINT32(unfolded_len, ==, get_utf8_codepoint_length(str, len));