[PATCH 10/11] config: fix a leak in git_config_copy_or_rename_section_in_file

From: Rubén Justo <rjusto@gmail.com>
Date: Jun 11, 2023, 18:50 UTC
Message-ID: <3ee93720-dce0-8f90-68bf-0242e5731a36@gmail.com>
In-Reply-To: <9eb931e7-dd18-8ce8-4d4a-cf3d85066189@gmail.com>

A branch can have its configuration spread over several configuration sections. This situation was already foreseen in 52d59cc645 (branch: add a --copy (-c) option to go with --move (-m), 2017-06-18) when "branch -c" was introduced.

Unfortunately, a leak was also introduced:

   $ git branch foo
   $ cat >> .git/config <<EOF
   [branch "foo"]
   	some-key-a = a value
   [branch "foo"]
   	some-key-b = b value
   [branch "foo"]
   	some-key-c = c value
   EOF
   $ git branch -c foo bar

   Direct leak of 130 byte(s) in 2 object(s) allocated from:
       ... in xrealloc wrapper.c
       ... in strbuf_grow strbuf.c
       ... in strbuf_vaddf strbuf.c
       ... in strbuf_addf strbuf.c
       ... in store_create_section config.c
       ... in git_config_copy_or_rename_section_in_file config.c
       ... in git_config_copy_section_in_file config.c
       ... in git_config_copy_section config.c
       ... in copy_or_rename_branch builtin/branch.c
       ... in cmd_branch builtin/branch.c
       ... in run_builtin git.c

Let's fix it.

Signed-off-by: Rubén Justo <rjusto@gmail.com>
---
 config.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/config.c b/config.c
index 39a7d7422c..207e4394a3 100644
--- a/config.c
+++ b/config.c
@@ -3833,6 +3833,7 @@ static int git_config_copy_or_rename_section_in_file(const char *config_filename
 						output[0] = '\t';
 					}
 				} else {
+					strbuf_release(&copystr);
 					copystr = store_create_section(new_name, &store);
 				}
 			}

-- 
2.40.1