[PATCH 07/12] read-cache: call diff_setup_done to avoid leak

From: andrzej@ahunt.org <andrzej@ahunt.org>
Date: Jun 20, 2021, 15:11 UTC
Message-ID: <20210620151204.19260-8-andrzej@ahunt.org>
In-Reply-To: <20210620151204.19260-1-andrzej@ahunt.org>

From: Andrzej Hunt <ajrhunt@google.com>

repo_diff_setup() calls through to diff.c's static prep_parse_options(), which in turn allocates a new array into diff_opts.parseopts. diff_setup_done() is responsible for freeing that array, and has the benefit of verifying diff_opts too - hence we add a call to diff_setup_done() to avoid leaking parseopts.

Output from the leak as found while running t0090 with LSAN:

Direct leak of 7120 byte(s) in 1 object(s) allocated from:
    #0 0x49a82d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0xa8bf89 in do_xmalloc wrapper.c:41:8
    #2 0x7a7bae in prep_parse_options diff.c:5636:2
    #3 0x7a7bae in repo_diff_setup diff.c:4611:2
    #4 0x93716c in repo_index_has_changes read-cache.c:2518:3
    #5 0x872233 in unclean merge-ort-wrappers.c:12:14
    #6 0x872233 in merge_ort_recursive merge-ort-wrappers.c:53:6
    #7 0x5d5b11 in try_merge_strategy builtin/merge.c:752:12
    #8 0x5d0b6b in cmd_merge builtin/merge.c:1666:9
    #9 0x4ce83e in run_builtin git.c:475:11
    #10 0x4ccafe in handle_builtin git.c:729:3
    #11 0x4cb01c in run_argv git.c:818:4
    #12 0x4cb01c in cmd_main git.c:949:19
    #13 0x6bdc2d in main common-main.c:52:11
    #14 0x7f551eb51349 in __libc_start_main (/lib64/libc.so.6+0x24349)

SUMMARY: AddressSanitizer: 7120 byte(s) leaked in 1 allocation(s)

Signed-off-by: Andrzej Hunt <andrzej@ahunt.org>
---
 read-cache.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/read-cache.c b/read-cache.c
index 77961a3885..212d604dd3 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2487,37 +2487,38 @@ int unmerged_index(const struct index_state *istate)
 int repo_index_has_changes(struct repository *repo,
 			   struct tree *tree,
 			   struct strbuf *sb)
 {
 	struct index_state *istate = repo->index;
 	struct object_id cmp;
 	int i;
 
 	if (tree)
 		cmp = tree->object.oid;
 	if (tree || !get_oid_tree("HEAD", &cmp)) {
 		struct diff_options opt;
 
 		repo_diff_setup(repo, &opt);
 		opt.flags.exit_with_status = 1;
 		if (!sb)
 			opt.flags.quick = 1;
+		diff_setup_done(&opt);
 		do_diff_cache(&cmp, &opt);
 		diffcore_std(&opt);
 		for (i = 0; sb && i < diff_queued_diff.nr; i++) {
 			if (i)
 				strbuf_addch(sb, ' ');
 			strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
 		}
 		diff_flush(&opt);
 		return opt.flags.has_changes != 0;
 	} else {
 		/* TODO: audit for interaction with sparse-index. */
 		ensure_full_index(istate);
 		for (i = 0; sb && i < istate->cache_nr; i++) {
 			if (i)
 				strbuf_addch(sb, ' ');
 			strbuf_addstr(sb, istate->cache[i]->name);
 		}
 		return !!istate->cache_nr;
 	}
 }

-- 
2.26.2