treewide: fix various bugs w/ OpenSSL 3+ EVP API

The OpenSSL 3+ EVP API for SHA-* cannot support our prior use cases
supported by other SHA-* implementations.  It has the following
differences:

1. ->init_fn is required before all use
2. struct assignments don't work and requires ->clone_fn
3. can't support ->update_fn after ->final_*fn

While fixing cases 1 and 2 is merely the matter of calling ->init_fn and
->clone_fn as appropriate, fixing case 3 requires calling ->final_*fn on
a temporary context that's cloned from the primary context.

Reported-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/ZPCL11k38PXTkFga@debian.me/
Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Fixes: 3e440ea0aba0 ("sha256: avoid functions deprecated in OpenSSL 3+")
Fixes: bda9c12073e7 ("avoid SHA-1 functions deprecated in OpenSSL 3+")
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fast-import.c

@@ -1103,6 +1103,7 @@ static void stream_blob(uintmax_t len, struct object_id *oidout, uintmax_t mark)
 		|| (pack_size + PACK_SIZE_THRESHOLD + len) < pack_size)
 		cycle_packfile();
 
+	the_hash_algo->init_fn(&checkpoint.ctx);
 	hashfile_checkpoint(pack_file, &checkpoint);
 	offset = checkpoint.offset;
 

builtin/index-pack.c

@@ -1166,6 +1166,7 @@ static void parse_pack_objects(unsigned char *hash)
 	struct ofs_delta_entry *ofs_delta = ofs_deltas;
 	struct object_id ref_delta_oid;
 	struct stat st;
+	git_hash_ctx tmp_ctx;
 
 	if (verbose)
 		progress = start_progress(
@@ -1202,7 +1203,9 @@ static void parse_pack_objects(unsigned char *hash)
 
 	/* Check pack integrity */
 	flush();
-	the_hash_algo->final_fn(hash, &input_ctx);
+	the_hash_algo->init_fn(&tmp_ctx);
+	the_hash_algo->clone_fn(&tmp_ctx, &input_ctx);
+	the_hash_algo->final_fn(hash, &tmp_ctx);
 	if (!hasheq(fill(the_hash_algo->rawsz), hash))
 		die(_("pack is corrupted (SHA1 mismatch)"));
 	use(the_hash_algo->rawsz);

builtin/unpack-objects.c

@@ -608,6 +608,7 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix UNUSED)
 {
 	int i;
 	struct object_id oid;
+	git_hash_ctx tmp_ctx;
 
 	read_replace_refs = 0;
 
@@ -668,7 +669,9 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix UNUSED)
 	the_hash_algo->init_fn(&ctx);
 	unpack_all();
 	the_hash_algo->update_fn(&ctx, buffer, offset);
-	the_hash_algo->final_oid_fn(&oid, &ctx);
+	the_hash_algo->init_fn(&tmp_ctx);
+	the_hash_algo->clone_fn(&tmp_ctx, &ctx);
+	the_hash_algo->final_oid_fn(&oid, &tmp_ctx);
 	if (strict) {
 		write_rest();
 		if (fsck_finish(&fsck_options))

bulk-checkin.c

@@ -270,6 +270,7 @@ static int deflate_to_pack(struct bulk_checkin_packfile *state,
 					  type, size);
 	the_hash_algo->init_fn(&ctx);
 	the_hash_algo->update_fn(&ctx, obuf, header_len);
+	the_hash_algo->init_fn(&checkpoint.ctx);
 
 	/* Note: idx is non-NULL when we are writing */
 	if ((flags & HASH_WRITE_OBJECT) != 0)

csum-file.c

@@ -208,7 +208,7 @@ int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint
 	    lseek(f->fd, offset, SEEK_SET) != offset)
 		return -1;
 	f->total = offset;
-	f->ctx = checkpoint->ctx;
+	the_hash_algo->clone_fn(&f->ctx, &checkpoint->ctx);
 	f->offset = 0; /* hashflush() was called in checkpoint */
 	return 0;
 }