gguf: fix failure on version == 0 (ggml-org#13956)

Author: JohannesGaessler

ggml/src/gguf.cpp

@@ -347,25 +347,28 @@ struct gguf_context * gguf_init_from_file_impl(FILE * file, struct gguf_init_par
     int64_t n_tensors = 0;
 
     if (ok && gr.read(ctx->version)) {
+        if (ok && ctx->version == 0) {
+            GGML_LOG_ERROR("%s: bad GGUF version: %" PRIu32 "\n", __func__, ctx->version);
+            ok = false;
+        }
+
         /*
          * bit layout is different when reading non-native endian models.
          * assuming that the GGUF version is 3, the non-native endian model
          * would read it as 0x30000000. we can use the AND operation against
          * the last 4 hexadecimal digits to check if the model is the same
          * endianness as the host system.
         */
-        if ((ctx->version & 0x0000FFFF) == 0x00000000) {
+        if (ok && (ctx->version & 0x0000FFFF) == 0x00000000) {
             GGML_LOG_ERROR("%s: failed to load model: this GGUF file version %" PRIu32 " is extremely large, is there a mismatch between the host and model endianness?\n", __func__, ctx->version);
-            gguf_free(ctx);
-            return nullptr;
+            ok = false;
         }
 
-        GGML_ASSERT(ctx->version > 0 && ctx->version <= 65535);
-        if (ctx->version == 1) {
+        if (ok && ctx->version == 1) {
             GGML_LOG_ERROR("%s: GGUFv1 is no longer supported, please use a more up-to-date version\n", __func__);
             ok = false;
         }
-        if (ctx->version > GGUF_VERSION) {
+        if (ok && ctx->version > GGUF_VERSION) {
             GGML_LOG_ERROR("%s: this GGUF file is version %" PRIu32 " but this software only supports up to version %d\n",
                 __func__, ctx->version, GGUF_VERSION);
             ok = false;

tests/test-gguf.cpp

@@ -16,6 +16,7 @@ constexpr int offset_has_data    = 3000;
 
 enum handcrafted_file_type {
     HANDCRAFTED_HEADER_BAD_MAGIC           =  10,
+    HANDCRAFTED_HEADER_BAD_VERSION_0       =  15,
     HANDCRAFTED_HEADER_BAD_VERSION_1       =  20,
     HANDCRAFTED_HEADER_BAD_VERSION_FUTURE  =  30,
     HANDCRAFTED_HEADER_BAD_N_TENSORS       =  40,
@@ -51,6 +52,7 @@ enum handcrafted_file_type {
 static std::string handcrafted_file_type_name(const enum handcrafted_file_type hft) {
     switch (hft) {
         case HANDCRAFTED_HEADER_BAD_MAGIC:           return "HEADER_BAD_MAGIC";
+        case HANDCRAFTED_HEADER_BAD_VERSION_0:       return "HEADER_BAD_VERSION_0";
         case HANDCRAFTED_HEADER_BAD_VERSION_1:       return "HEADER_BAD_VERSION_1";
         case HANDCRAFTED_HEADER_BAD_VERSION_FUTURE:  return "HEADER_BAD_VERSION_FUTURE";
         case HANDCRAFTED_HEADER_BAD_N_KV:            return "HEADER_BAD_N_KV";
@@ -171,7 +173,10 @@ static FILE * get_handcrafted_file(const unsigned int seed, const enum handcraft
         helper_write(file, GGUF_MAGIC, 4);
     }
 
-    if (hft == HANDCRAFTED_HEADER_BAD_VERSION_1) {
+    if (hft == HANDCRAFTED_HEADER_BAD_VERSION_0) {
+        const uint32_t version = 0;
+        helper_write(file, version);
+    } else if (hft == HANDCRAFTED_HEADER_BAD_VERSION_1) {
         const uint32_t version = 1;
         helper_write(file, version);
     } else if (hft == HANDCRAFTED_HEADER_BAD_VERSION_FUTURE) {
@@ -660,6 +665,7 @@ static std::pair<int, int> test_handcrafted_file(const unsigned int seed) {
 
     const std::vector<handcrafted_file_type> hfts = {
         HANDCRAFTED_HEADER_BAD_MAGIC,
+        HANDCRAFTED_HEADER_BAD_VERSION_0,
         HANDCRAFTED_HEADER_BAD_VERSION_1,
         HANDCRAFTED_HEADER_BAD_VERSION_FUTURE,
         HANDCRAFTED_HEADER_BAD_N_KV,