Subject: [PATCH 1/7] symbolic-ref: don't leak shortened refname in check_symref()

From: "Andrzej Hunt via GitGitGadget" <[email-masked]>
Date: Mon, 08 Mar 2021 18:36:14 +0000

From: Andrzej Hunt <[email-masked]>

This leak has existed since:
9ab55daa55 (git symbolic-ref --delete $symref, 2012-10-21)

This leak was found when running t0001 with LSAN, see also LSAN output
below:

Direct leak of 19 byte(s) in 1 object(s) allocated from:
    #0 0x486514 in strdup /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_interceptors.cpp:452:3
    #1 0x9ab048 in xstrdup /home/ahunt/oss-fuzz/git/wrapper.c:29:14
    #2 0x8b452f in refs_shorten_unambiguous_ref /home/ahunt/oss-fuzz/git/refs.c
    #3 0x8b47e8 in shorten_unambiguous_ref /home/ahunt/oss-fuzz/git/refs.c:1287:9
    #4 0x679fce in check_symref /home/ahunt/oss-fuzz/git/builtin/symbolic-ref.c:28:14
    #5 0x679ad8 in cmd_symbolic_ref /home/ahunt/oss-fuzz/git/builtin/symbolic-ref.c:70:9
    #6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
    #7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
    #8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
    #9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
    #10 0x69cc6e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
    #11 0x7f98388a4349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Signed-off-by: Andrzej Hunt <[email-masked]>
---
 builtin/symbolic-ref.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c
index 80237f0df10f..8cf52599693a 100644
--- a/builtin/symbolic-ref.c
+++ b/builtin/symbolic-ref.c
@@ -24,9 +24,15 @@ static int check_symref(const char *HEAD, int quiet, int shorten, int print)
 			return 1;
 	}
 	if (print) {
-		if (shorten)
-			refname = shorten_unambiguous_ref(refname, 0);
-		puts(refname);
+		if (shorten) {
+			const char *shortened_refname;
+
+			shortened_refname = shorten_unambiguous_ref(refname, 0);
+			puts(shortened_refname);
+			free((void *)shortened_refname);
+		} else {
+			puts(refname);
+		}
 	}
 	return 0;
 }
-- 
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