Subject: [PATCH] builtin/submodule--helper: fix leak when remote_submodule_branch() failed

From: "Lidong Yan via GitGitGadget" <[email-masked]>
Date: Sun, 08 Jun 2025 03:56:59 +0000

From: Lidong Yan <[email-masked]>

In builtin/submodule--helper.c:update_submodule(), the variable
remote_name is allocated in get_default_remote_submodule() but
may be leaked if remote_submodule_branch() fails. Although it is
unlikely that remote_submodule_branch() would fail after successfully
obtaining a remote ref name from get_default_remote_submodule(),
it is still possible. To prevent a potential memory leak, add a
call to free(remote_name) at the early exit point.

Signed-off-by: Lidong Yan <[email-masked]>
---
    submodule--helper: fix leak when remote_submodule_branch() failed
    
    In builtin/submodule--helper.c:update_submodule(), remote_name is
    allocated in get_default_remote_submodule() but may leak due to failure
    of remote_submodule_branch. Add free(remote_name) at the eraly exit
    point.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1987%2Fbrandb97%2Ffix-update-submodule-leak-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1987/brandb97/fix-update-submodule-leak-v1
Pull-Request: https://github.com/git/git/pull/1987

 builtin/submodule--helper.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 53da2116ddf..640c0059c3e 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2660,8 +2660,10 @@ static int update_submodule(struct update_data *update_data)
 		if (code)
 			return code;
 		code = remote_submodule_branch(update_data->sm_path, &branch);
-		if (code)
+		if (code) {
+			free(remote_name);
 			return code;
+		}
 		remote_ref = xstrfmt("refs/remotes/%s/%s", remote_name, branch);
 
 		free(remote_name);

base-commit: 7014b55638da979331baf8dc31c4e1d697cf2d67
-- 
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