Handle cloning of objects larger than 4GB on Windows

Makefile

@@ -872,6 +872,7 @@ TEST_BUILTINS_OBJS += test-submodule-config.o
 TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o
 TEST_BUILTINS_OBJS += test-submodule.o
 TEST_BUILTINS_OBJS += test-subprocess.o
+TEST_BUILTINS_OBJS += test-synthesize.o
 TEST_BUILTINS_OBJS += test-trace2.o
 TEST_BUILTINS_OBJS += test-truncate.o
 TEST_BUILTINS_OBJS += test-userdiff.o

builtin/index-pack.c

@@ -37,7 +37,7 @@ static const char index_pack_usage[] =
 
 struct object_entry {
 	struct pack_idx_entry idx;
-	unsigned long size;
+	size_t size;
 	unsigned char hdr_size;
 	signed char type;
 	signed char real_type;
@@ -469,7 +469,7 @@ static int is_delta_type(enum object_type type)
 	return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 }
 
-static void *unpack_entry_data(off_t offset, unsigned long size,
+static void *unpack_entry_data(off_t offset, size_t size,
 			       enum object_type type, struct object_id *oid)
 {
 	static char fixed_buf[8192];
@@ -524,7 +524,8 @@ static void *unpack_raw_entry(struct object_entry *obj,
 			      struct object_id *oid)
 {
 	unsigned char *p;
-	unsigned long size, c;
+	size_t size;
+	unsigned long c;
 	off_t base_offset;
 	unsigned shift;
 	void *data;
@@ -542,7 +543,7 @@ static void *unpack_raw_entry(struct object_entry *obj,
 		p = fill(1);
 		c = *p;
 		use(1);
-		size += (c & 0x7f) << shift;
+		size += ((size_t)c & 0x7f) << shift;
 		shift += 7;
 	}
 	obj->size = size;

builtin/pack-objects.c

@@ -629,14 +629,21 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 	struct packed_git *p = IN_PACK(entry);
 	struct pack_window *w_curs = NULL;
 	uint32_t pos;
-	off_t offset;
+	off_t offset, cur;
 	enum object_type type = oe_type(entry);
+	enum object_type in_pack_type;
 	off_t datalen;
 	unsigned char header[MAX_PACK_OBJECT_HEADER],
 		      dheader[MAX_PACK_OBJECT_HEADER];
 	unsigned hdrlen;
 	const unsigned hashsz = the_hash_algo->rawsz;
-	unsigned long entry_size = SIZE(entry);
+	size_t entry_size;
+
+	cur = entry->in_pack_offset;
+	in_pack_type = unpack_object_header(p, &w_curs, &cur, &entry_size);
+	if (in_pack_type < 0)
+		die(_("write_reuse_object: unable to parse object header of %s"),
+		    oid_to_hex(&entry->idx.oid));
 
 	if (DELTA(entry))
 		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
@@ -1087,7 +1094,7 @@ static void write_reused_pack_one(struct packed_git *reuse_packfile,
 {
 	off_t offset, next, cur;
 	enum object_type type;
-	unsigned long size;
+	size_t size;
 
 	offset = pack_pos_to_offset(reuse_packfile, pos);
 	next = pack_pos_to_offset(reuse_packfile, pos + 1);
@@ -2243,7 +2250,7 @@ static void check_object(struct object_entry *entry, uint32_t object_index)
 		off_t ofs;
 		unsigned char *buf, c;
 		enum object_type type;
-		unsigned long in_pack_size;
+		size_t in_pack_size;
 
 		buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
 
@@ -2734,16 +2741,18 @@ unsigned long oe_get_size_slow(struct packing_data *pack,
 	struct pack_window *w_curs;
 	unsigned char *buf;
 	enum object_type type;
-	unsigned long used, avail, size;
+	unsigned long used, avail;
+	size_t size;
 
 	if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
+		unsigned long sz;
 		packing_data_lock(&to_pack);
 		if (odb_read_object_info(the_repository->objects,
-					 &e->idx.oid, &size) < 0)
+					 &e->idx.oid, &sz) < 0)
 			die(_("unable to get size of %s"),
 			    oid_to_hex(&e->idx.oid));
 		packing_data_unlock(&to_pack);
-		return size;
+		return sz;
 	}
 
 	p = oe_in_pack(pack, e);

builtin/unpack-objects.c

@@ -533,7 +533,8 @@ static void unpack_one(unsigned nr)
 {
 	unsigned shift;
 	unsigned char *pack;
-	unsigned long size, c;
+	size_t size;
+	unsigned long c;
 	enum object_type type;
 
 	obj_list[nr].offset = consumed_bytes;
@@ -548,7 +549,7 @@ static void unpack_one(unsigned nr)
 		pack = fill(1);
 		c = *pack;
 		use(1);
-		size += (c & 0x7f) << shift;
+		size += ((size_t)c & 0x7f) << shift;
 		shift += 7;
 	}
 

compat/zlib-compat.h

@@ -7,6 +7,8 @@
 # define z_stream_s zng_stream_s
 # define gz_header_s zng_gz_header_s
 
+# define adler32(adler, buf, len) zng_adler32(adler, buf, len)
+
 # define crc32(crc, buf, len) zng_crc32(crc, buf, len)
 
 # define inflate(strm, bits) zng_inflate(strm, bits)

delta.h

@@ -86,8 +86,11 @@ void *patch_delta(const void *src_buf, unsigned long src_size,
  * This must be called twice on the delta data buffer, first to get the
  * expected source buffer size, and again to get the target buffer size.
  */
-static inline unsigned long get_delta_hdr_size(const unsigned char **datap,
-					       const unsigned char *top)
+/*
+ * Size_t variant that doesn't truncate - use for >4GB objects on Windows.
+ */
+static inline size_t get_delta_hdr_size_sz(const unsigned char **datap,
+					   const unsigned char *top)
 {
 	const unsigned char *data = *datap;
 	size_t cmd, size = 0;
@@ -98,6 +101,13 @@ static inline unsigned long get_delta_hdr_size(const unsigned char **datap,
 		i += 7;
 	} while (cmd & 0x80 && data < top);
 	*datap = data;
+	return size;
+}
+
+static inline unsigned long get_delta_hdr_size(const unsigned char **datap,
+					       const unsigned char *top)
+{
+	size_t size = get_delta_hdr_size_sz(datap, top);
 	return cast_size_t_to_ulong(size);
 }
 

git-zlib.c

@@ -30,6 +30,9 @@ static const char *zerr_to_string(int status)
  */
 /* #define ZLIB_BUF_MAX ((uInt)-1) */
 #define ZLIB_BUF_MAX ((uInt) 1024 * 1024 * 1024) /* 1GB */
+
+/* uLong is 32-bit on Windows, even on 64-bit systems */
+#define ULONG_MAX_VALUE maximum_unsigned_value_of_type(uLong)
 static inline uInt zlib_buf_cap(unsigned long len)
 {
 	return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len;
@@ -39,31 +42,37 @@ static void zlib_pre_call(git_zstream *s)
 {
 	s->z.next_in = s->next_in;
 	s->z.next_out = s->next_out;
-	s->z.total_in = s->total_in;
-	s->z.total_out = s->total_out;
+	s->z.total_in = (uLong)(s->total_in & ULONG_MAX_VALUE);
+	s->z.total_out = (uLong)(s->total_out & ULONG_MAX_VALUE);
 	s->z.avail_in = zlib_buf_cap(s->avail_in);
 	s->z.avail_out = zlib_buf_cap(s->avail_out);
 }
 
 static void zlib_post_call(git_zstream *s, int status)
 {
-	unsigned long bytes_consumed;
-	unsigned long bytes_produced;
+	size_t bytes_consumed;
+	size_t bytes_produced;
 
 	bytes_consumed = s->z.next_in - s->next_in;
 	bytes_produced = s->z.next_out - s->next_out;
-	if (s->z.total_out != s->total_out + bytes_produced)
+	/*
+	 * zlib's total_out/total_in are uLong which may wrap for >4GB.
+	 * We track our own totals and verify only the low bits match.
+	 */
+	if ((s->z.total_out & ULONG_MAX_VALUE) !=
+	    ((s->total_out + bytes_produced) & ULONG_MAX_VALUE))
 		BUG("total_out mismatch");
 	/*
 	 * zlib does not update total_in when it returns Z_NEED_DICT,
 	 * causing a mismatch here. Skip the sanity check in that case.
 	 */
 	if (status != Z_NEED_DICT &&
-	    s->z.total_in != s->total_in + bytes_consumed)
+	    (s->z.total_in & ULONG_MAX_VALUE) !=
+	    ((s->total_in + bytes_consumed) & ULONG_MAX_VALUE))
 		BUG("total_in mismatch");
 
-	s->total_out = s->z.total_out;
-	s->total_in = s->z.total_in;
+	s->total_out += bytes_produced;
+	s->total_in += bytes_consumed;
 	/* zlib-ng marks `next_in` as `const`, so we have to cast it away. */
 	s->next_in = (unsigned char *) s->z.next_in;
 	s->next_out = s->z.next_out;

git-zlib.h

@@ -7,8 +7,8 @@ typedef struct git_zstream {
 	struct z_stream_s z;
 	unsigned long avail_in;
 	unsigned long avail_out;
-	unsigned long total_in;
-	unsigned long total_out;
+	size_t total_in;
+	size_t total_out;
 	unsigned char *next_in;
 	unsigned char *next_out;
 } git_zstream;

object-file.c

@@ -1118,7 +1118,7 @@ int odb_source_loose_write_stream(struct odb_source *source,
 	} while (ret == Z_OK || ret == Z_BUF_ERROR);
 
 	if (stream.total_in != len + hdrlen)
-		die(_("write stream object %ld != %"PRIuMAX), stream.total_in,
+		die(_("write stream object %"PRIuMAX" != %"PRIuMAX), (uintmax_t)stream.total_in,
 		    (uintmax_t)len + hdrlen);
 
 	/*
@@ -2326,6 +2326,7 @@ int odb_source_loose_read_object_stream(struct odb_read_stream **out,
 	struct object_info oi = OBJECT_INFO_INIT;
 	struct odb_loose_read_stream *st;
 	unsigned long mapsize;
+	unsigned long size_ul;
 	void *mapped;
 
 	mapped = odb_source_loose_map_object(source, oid, &mapsize);
@@ -2349,11 +2350,18 @@ int odb_source_loose_read_object_stream(struct odb_read_stream **out,
 		goto error;
 	}
 
-	oi.sizep = &st->base.size;
+	/*
+	 * object_info.sizep is unsigned long* (32-bit on Windows), but
+	 * st->base.size is size_t (64-bit). Use temporary variable.
+	 * Note: loose objects >4GB would still truncate here, but such
+	 * large loose objects are uncommon (they'd normally be packed).
+	 */
+	oi.sizep = &size_ul;
 	oi.typep = &st->base.type;
 
 	if (parse_loose_header(st->hdr, &oi) < 0 || st->base.type < 0)
 		goto error;
+	st->base.size = size_ul;
 
 	st->mapped = mapped;
 	st->mapsize = mapsize;

odb/streaming.c

@@ -157,15 +157,26 @@ static int open_istream_incore(struct odb_read_stream **out,
 		.base.read = read_istream_incore,
 	};
 	struct odb_incore_read_stream *st;
+	unsigned long size_ul;
 	int ret;
 
 	oi.typep = &stream.base.type;
-	oi.sizep = &stream.base.size;
+	/*
+	 * object_info.sizep is unsigned long* (32-bit on Windows), but
+	 * stream.base.size is size_t (64-bit). We use a temporary variable
+	 * because the types are incompatible. Note: this path still truncates
+	 * for >4GB objects, but large objects should use pack streaming
+	 * (packfile_store_read_object_stream) which handles size_t properly.
+	 * This incore fallback is only used for small objects or when pack
+	 * streaming is unavailable.
+	 */
+	oi.sizep = &size_ul;
 	oi.contentp = (void **)&stream.buf;
 	ret = odb_read_object_info_extended(odb, oid, &oi,
 					    OBJECT_INFO_DIE_IF_CORRUPT);
 	if (ret)
 		return ret;
+	stream.base.size = size_ul;
 
 	CALLOC_ARRAY(st, 1);
 	*st = stream;

odb/streaming.h

@@ -21,7 +21,7 @@ struct odb_read_stream {
 	odb_read_stream_close_fn close;
 	odb_read_stream_read_fn read;
 	enum object_type type;
-	unsigned long size; /* inflated size of full object */
+	size_t size; /* inflated size of full object */
 };
 
 /*

oss-fuzz/fuzz-pack-headers.c

@@ -6,7 +6,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 {
 	enum object_type type;
-	unsigned long len;
+	size_t len;
 
 	unpack_object_header_buffer((const unsigned char *)data,
 				    (unsigned long)size, &type, &len);

pack-bitmap.c

@@ -2270,7 +2270,7 @@ static int try_partial_reuse(struct bitmap_index *bitmap_git,
 {
 	off_t delta_obj_offset;
 	enum object_type type;
-	unsigned long size;
+	size_t size;
 
 	if (pack_pos >= pack->p->num_objects)
 		return -1; /* not actually in the pack */

pack-check.c

@@ -110,7 +110,7 @@ static int verify_packfile(struct repository *r,
 		void *data;
 		struct object_id oid;
 		enum object_type type;
-		unsigned long size;
+		size_t size;
 		off_t curpos;
 		int data_valid;
 
@@ -143,7 +143,9 @@ static int verify_packfile(struct repository *r,
 			data = NULL;
 			data_valid = 0;
 		} else {
-			data = unpack_entry(r, p, entries[i].offset, &type, &size);
+			unsigned long sz;
+			data = unpack_entry(r, p, entries[i].offset, &type, &sz);
+			size = sz;
 			data_valid = 1;
 		}