On Wed, Jul 09, 2025 at 02:49:14PM -0700, Jacob Keller wrote:
> find_cfg_ent() allocates a struct reflog_expire_entry_option via
> FLEX_ALLOC_MEM and returns its pointer to reflog_expire_config(). The
> function exits without freeing the memory:
>
> Direct leak of 39 byte(s) in 1 object(s) allocated from:
> #0 0x7ff975ee6883 in calloc (/lib64/libasan.so.8+0xe6883)
> #1 0x0000010edada in xcalloc ../wrapper.c:154
> #2 0x000000df0898 in find_cfg_ent ../reflog.c:28
> #3 0x000000df0898 in reflog_expire_config ../reflog.c:70
> #4 0x00000095c451 in configset_iter ../config.c:2116
> #5 0x0000006d29e7 in git_config ../config.h:724
> #6 0x0000006d29e7 in cmd_reflog_expire ../builtin/reflog.c:205
> #7 0x0000006d504c in cmd_reflog ../builtin/reflog.c:419
> #8 0x0000007e4054 in run_builtin ../git.c:480
> #9 0x0000007e4054 in handle_builtin ../git.c:746
> #10 0x0000007e8a35 in run_argv ../git.c:813
> #11 0x0000007e8a35 in cmd_main ../git.c:953
> #12 0x000000441e8f in main ../common-main.c:9
> #13 0x7ff9754115f4 in __libc_start_call_main (/lib64/libc.so.6+0x35f4)
> #14 0x7ff9754116a7 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x36a7)
> #15 0x000000444184 in _start (/home/jekeller/libexec/git-core/git+0x444184)
>
> Close this leak by freeing the entry pointer on exit of the
> reflog_expire_config() function. This frees both the entry structure and
> its embedded pattern array thanks to the use of FLEX_ALLOC_MEM.
Hmm, this can't be right, can it? The end of reflog_expire_config()
looks like this:
ent = find_cfg_ent(opts, pattern, pattern_len);
if (!ent)
return -1;
switch (slot) {
case REFLOG_EXPIRE_TOTAL:
ent->expire_total = expire;
break;
case REFLOG_EXPIRE_UNREACH:
ent->expire_unreachable = expire;
break;
}
return 0;
So if we free(ent), then what was the point of the function? We'd set
some fields in it and then throw it away?
And indeed, find_cfg_ent() seems to add the newly allocated entry to the
list opt->entries list. So by freeing here, we're leaving a dangling
pointer in that list.
Probably that list needs to be cleaned up when cmd_reflog_expire()
finishes?
-Peff
