Re: [PATCH 3/5 v2] load_imsm_mpb: fix double free

[Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>]

On Thu, 9 Jun 2022 11:07:56 +0800
Wu Guanghao <wuguanghao3@huawei.com> wrote:

> When free(super->buf) but not set super->buf = NULL, will be double free.
> 
> get_super_block
> 	err = load_and_parse_mpb
> 		load_imsm_mpb(.., s, ..)
> 			if (posix_memalign(&super->buf, MAX_SECTOR_SIZE,
> super->len) != 0) // true, super->buf != NULL if
> (posix_memalign(&super->migr_rec_buf, MAX_SECTOR_SIZE,); // false
> free(super->buf); //but super->buf not set NULL return 2;
> 
> 	if err ! = 0
> 		if (s)
> 			free_imsm(s)
> 				 __free_imsm(s)
> 					if (s)
> 						free(s->buf); //double free
> 
> Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
> ---
>  super-intel.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/super-intel.c b/super-intel.c
> index ba3bd41f..ee9e112e 100644
> --- a/super-intel.c
> +++ b/super-intel.c
> @@ -4453,6 +4453,7 @@ static int load_imsm_mpb(int fd, struct intel_super
> *super, char *devname) MIGR_REC_BUF_SECTORS*MAX_SECTOR_SIZE) != 0) {
>                 pr_err("could not allocate migr_rec buffer\n");
>                 free(super->buf);
> +               super->buf = NULL;
>                 return 2;
>         }
>         super->clean_migration_record_by_mdmon = 0;
> --
> 2.27.0

Reviewed-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>