Merge branch 'tb/weak-sha1-for-tail-sum'

The checksum at the tail of files are now computed without
collision detection protection.  This is safe as the consumer of
the information to protect itself from replay attacks checks for
hash collisions independently.

* tb/weak-sha1-for-tail-sum:
  csum-file.c: use unsafe SHA-1 implementation when available
  Makefile: allow specifying a SHA-1 for non-cryptographic uses
  hash.h: scaffolding for _unsafe hashing variants
  sha1: do not redefine `platform_SHA_CTX` and friends
  pack-objects: use finalize_object_file() to rename pack/idx/etc
  finalize_object_file(): implement collision check
  finalize_object_file(): refactor unlink_or_warn() placement
  finalize_object_file(): check for name collision before renaming

1 files changed, 9 insertions, 9 deletions

diff --git a/csum-file.c b/csum-file.c
index bf82ad8f9f..c203ebf11b 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -50,7 +50,7 @@ void hashflush(struct hashfile *f)
 
 	if (offset) {
 		if (!f->skip_hash)
-			the_hash_algo->update_fn(&f->ctx, f->buffer, offset);
+			the_hash_algo->unsafe_update_fn(&f->ctx, f->buffer, offset);
 		flush(f, f->buffer, offset);
 		f->offset = 0;
 	}
@@ -73,7 +73,7 @@ int finalize_hashfile(struct hashfile *f, unsigned char *result,
 	if (f->skip_hash)
 		hashclr(f->buffer, the_repository->hash_algo);
 	else
-		the_hash_algo->final_fn(f->buffer, &f->ctx);
+		the_hash_algo->unsafe_final_fn(f->buffer, &f->ctx);
 
 	if (result)
 		hashcpy(result, f->buffer, the_repository->hash_algo);
@@ -128,7 +128,7 @@ void hashwrite(struct hashfile *f, const void *buf, unsigned int count)
 			 * f->offset is necessarily zero.
 			 */
 			if (!f->skip_hash)
-				the_hash_algo->update_fn(&f->ctx, buf, nr);
+				the_hash_algo->unsafe_update_fn(&f->ctx, buf, nr);
 			flush(f, buf, nr);
 		} else {
 			/*
@@ -174,7 +174,7 @@ static struct hashfile *hashfd_internal(int fd, const char *name,
 	f->name = name;
 	f->do_crc = 0;
 	f->skip_hash = 0;
-	the_hash_algo->init_fn(&f->ctx);
+	the_hash_algo->unsafe_init_fn(&f->ctx);
 
 	f->buffer_len = buffer_len;
 	f->buffer = xmalloc(buffer_len);
@@ -208,7 +208,7 @@ void hashfile_checkpoint(struct hashfile *f, struct hashfile_checkpoint *checkpo
 {
 	hashflush(f);
 	checkpoint->offset = f->total;
-	the_hash_algo->clone_fn(&checkpoint->ctx, &f->ctx);
+	the_hash_algo->unsafe_clone_fn(&checkpoint->ctx, &f->ctx);
 }
 
 int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint)
@@ -219,7 +219,7 @@ int hashfile_truncate(struct hashfile *f, struct hashfile_checkpoint *checkpoint
 	    lseek(f->fd, offset, SEEK_SET) != offset)
 		return -1;
 	f->total = offset;
-	the_hash_algo->clone_fn(&f->ctx, &checkpoint->ctx);
+	the_hash_algo->unsafe_clone_fn(&f->ctx, &checkpoint->ctx);
 	f->offset = 0; /* hashflush() was called in checkpoint */
 	return 0;
 }
@@ -245,9 +245,9 @@ int hashfile_checksum_valid(const unsigned char *data, size_t total_len)
 	if (total_len < the_hash_algo->rawsz)
 		return 0; /* say "too short"? */
 
-	the_hash_algo->init_fn(&ctx);
-	the_hash_algo->update_fn(&ctx, data, data_len);
-	the_hash_algo->final_fn(got, &ctx);
+	the_hash_algo->unsafe_init_fn(&ctx);
+	the_hash_algo->unsafe_update_fn(&ctx, data, data_len);
+	the_hash_algo->unsafe_final_fn(got, &ctx);
 
 	return hasheq(got, data + data_len, the_repository->hash_algo);
 }