1 files changed, 105 insertions, 0 deletions
diff --git a/programs/fuzz/common.c b/programs/fuzz/common.c
new file mode 100644
index 00000000000..98aa4037b36
--- /dev/null
+++ b/programs/fuzz/common.c
@@ -0,0 +1,105 @@
+#include "common.h"
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "mbedtls/ctr_drbg.h"
+
+#if defined(MBEDTLS_PLATFORM_TIME_ALT)
+mbedtls_time_t dummy_constant_time(mbedtls_time_t *time)
+{
+    (void) time;
+    return 0x5af2a056;
+}
+#endif
+
+void dummy_init(void)
+{
+#if defined(MBEDTLS_PLATFORM_TIME_ALT)
+    mbedtls_platform_set_time(dummy_constant_time);
+#else
+    fprintf(stderr, "Warning: fuzzing without constant time\n");
+#endif
+}
+
+int dummy_send(void *ctx, const unsigned char *buf, size_t len)
+{
+    //silence warning about unused parameter
+    (void) ctx;
+    (void) buf;
+
+    //pretends we wrote everything ok
+    if (len > INT_MAX) {
+        return -1;
+    }
+    return (int) len;
+}
+
+int fuzz_recv(void *ctx, unsigned char *buf, size_t len)
+{
+    //reads from the buffer from fuzzer
+    fuzzBufferOffset_t *biomemfuzz = (fuzzBufferOffset_t *) ctx;
+
+    if (biomemfuzz->Offset == biomemfuzz->Size) {
+        //EOF
+        return 0;
+    }
+    if (len > INT_MAX) {
+        return -1;
+    }
+    if (len + biomemfuzz->Offset > biomemfuzz->Size) {
+        //do not overflow
+        len = biomemfuzz->Size - biomemfuzz->Offset;
+    }
+    memcpy(buf, biomemfuzz->Data + biomemfuzz->Offset, len);
+    biomemfuzz->Offset += len;
+    return (int) len;
+}
+
+int dummy_random(void *p_rng, unsigned char *output, size_t output_len)
+{
+    int ret;
+    size_t i;
+
+#if defined(MBEDTLS_CTR_DRBG_C)
+    //mbedtls_ctr_drbg_random requires a valid mbedtls_ctr_drbg_context in p_rng
+    if (p_rng != NULL) {
+        //use mbedtls_ctr_drbg_random to find bugs in it
+        ret = mbedtls_ctr_drbg_random(p_rng, output, output_len);
+    } else {
+        //fall through to pseudo-random
+        ret = 0;
+    }
+#else
+    (void) p_rng;
+    ret = 0;
+#endif
+    for (i = 0; i < output_len; i++) {
+        //replace result with pseudo random
+        output[i] = (unsigned char) rand();
+    }
+    return ret;
+}
+
+int dummy_entropy(void *data, unsigned char *output, size_t len)
+{
+    size_t i;
+    (void) data;
+
+    //use mbedtls_entropy_func to find bugs in it
+    //test performance impact of entropy
+    //ret = mbedtls_entropy_func(data, output, len);
+    for (i = 0; i < len; i++) {
+        //replace result with pseudo random
+        output[i] = (unsigned char) rand();
+    }
+    return 0;
+}
+
+int fuzz_recv_timeout(void *ctx, unsigned char *buf, size_t len,
+                      uint32_t timeout)
+{
+    (void) timeout;
+
+    return fuzz_recv(ctx, buf, len);
+}