TODO: Assert the preceding change, doesn't work...

This fails with e.g. this t9350-fast-export.sh test, perhaps we have a
\0-delimited and use that last byte for an implicit \n?

	+ git tag -a -m valentin muss
	=================================================================
	==32504==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60d0000005ab at pc 0x556431ac3cac bp 0x7ffe67fcff50 sp 0x7ffe67fcff48
	READ of size 1 at 0x60d0000005ab thread T0
	    #0 0x556431ac3cab in parse_tag_buffer tag.c:155
	    #1 0x5564319194f3 in parse_object_buffer object.c:245
	    #2 0x556431919a11 in parse_object object.c:298
	    #3 0x5564319e2e96 in write_ref_to_lockfile refs/files-backend.c:1781
	    #4 0x5564319e71e8 in lock_ref_for_update refs/files-backend.c:2590
	    #5 0x5564319e7db5 in files_transaction_prepare refs/files-backend.c:2763
	    git#6 0x5564319d41d9 in ref_transaction_prepare refs.c:2146
	    #7 0x5564319d4465 in ref_transaction_commit refs.c:2195
	    git#8 0x5564316706b9 in cmd_tag builtin/tag.c:630
	    git#9 0x5564314168ff in run_builtin git.c:466
	    git#10 0x5564314172ab in handle_builtin git.c:720
	    git#11 0x5564314179d5 in run_argv git.c:787
	    git#12 0x55643141874f in cmd_main git.c:920
	    git#13 0x556431695a4d in main common-main.c:56
	    git#14 0x7fa9ba2aa81c in __libc_start_main ../csu/libc-start.c:332
	    git#15 0x556431412209 in _start (git+0x1d2209)

	0x60d0000005ab is located 0 bytes to the right of 139-byte region [0x60d000000520,0x60d0000005ab)
	allocated by thread T0 here:
	    #0 0x7fa9ba5fc9cf in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:69
	    #1 0x556431b3f334 in do_xmalloc wrapper.c:51
	    #2 0x556431b3f43a in do_xmallocz wrapper.c:85
	    #3 0x556431b3f4ab in xmallocz wrapper.c:93
	    #4 0x556431902114 in unpack_loose_rest object-file.c:1312
	    #5 0x556431902ed9 in loose_object_info object-file.c:1479
	    git#6 0x556431903785 in do_oid_object_info_extended object-file.c:1577
	    #7 0x556431903b2d in oid_object_info_extended object-file.c:1639
	    git#8 0x556431903f3f in read_object object-file.c:1671
	    git#9 0x5564319043c7 in read_object_file_extended object-file.c:1714
	    git#10 0x556431917ff0 in repo_read_object_file object-store.h:253
	    git#11 0x5564319198b3 in parse_object object.c:290
	    git#12 0x5564319e2e96 in write_ref_to_lockfile refs/files-backend.c:1781
	    git#13 0x5564319e71e8 in lock_ref_for_update refs/files-backend.c:2590
	    git#14 0x5564319e7db5 in files_transaction_prepare refs/files-backend.c:2763
	    git#15 0x5564319d41d9 in ref_transaction_prepare refs.c:2146
	    git#16 0x5564319d4465 in ref_transaction_commit refs.c:2195
	    git#17 0x5564316706b9 in cmd_tag builtin/tag.c:630
	    git#18 0x5564314168ff in run_builtin git.c:466
	    git#19 0x5564314172ab in handle_builtin git.c:720
	    git#20 0x5564314179d5 in run_argv git.c:787
	    git#21 0x55643141874f in cmd_main git.c:920
	    git#22 0x556431695a4d in main common-main.c:56
	    git#23 0x7fa9ba2aa81c in __libc_start_main ../csu/libc-start.c:332
	    git#24 0x556431412209 in _start (git+0x1d2209)

	SUMMARY: AddressSanitizer: heap-buffer-overflow tag.c:155 in parse_tag_buffer
	Shadow bytes around the buggy address:
	  0x0c1a7fff8060: fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa fa
	  0x0c1a7fff8070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
	  0x0c1a7fff8080: 00 03 fa fa fa fa fa fa fa fa fd fd fd fd fd fd
	  0x0c1a7fff8090: fd fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa
	  0x0c1a7fff80a0: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00
	=>0x0c1a7fff80b0: 00 00 00 00 00[03]fa fa fa fa fa fa fa fa fa fa
	  0x0c1a7fff80c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
	  0x0c1a7fff80d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
	  0x0c1a7fff80e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
	  0x0c1a7fff80f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
	  0x0c1a7fff8100: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
	Shadow byte legend (one shadow byte represents 8 application bytes):

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>

Author: avar

tag.c

@@ -141,6 +141,9 @@ int parse_tag_buffer(struct repository *r, struct tag *item, const void *data, u
 	const char *tail = bufptr + size;
 	const char *nl;
 
+	if (0 && *(tail + 1) != '\0')
+		BUG("TODO: assert \\0-delimited buffer!");
+
 	if (item->object.parsed)
 		return 0;