On Thu, Jun 6, 2019 at 10:55 AM Gen Zhang <blackgod016574@xxxxxxxxx> wrote:
> In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
> returns NULL when fails. So 'arg' should be checked. And 'mnt_opts'
> should be freed when error.
>
> Signed-off-by: Gen Zhang <blackgod016574@xxxxxxxxx>
> Fixes: 99dbbb593fe6 ("selinux: rewrite selinux_sb_eat_lsm_opts()")
My comments about the subject and an empty line before label apply
here as well, but Paul can fix both easily when applying, so:
Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> ---
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3ec702c..13479cd 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2616,10 +2616,11 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> char *from = options;
> char *to = options;
> bool first = true;
> + int rc;
>
> while (1) {
> int len = opt_len(from);
> - int token, rc;
> + int token;
> char *arg = NULL;
>
> token = match_opt_prefix(from, len, &arg);
> @@ -2635,15 +2636,15 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> *q++ = c;
> }
> arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
> + if (!arg) {
> + rc = -ENOMEM;
> + goto free_opt;
> + }
> }
> rc = selinux_add_opt(token, arg, mnt_opts);
> if (unlikely(rc)) {
> kfree(arg);
> - if (*mnt_opts) {
> - selinux_free_mnt_opts(*mnt_opts);
> - *mnt_opts = NULL;
> - }
> - return rc;
> + goto free_opt;
> }
> } else {
> if (!first) { // copy with preceding comma
> @@ -2661,6 +2662,12 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> }
> *to = '\0';
> return 0;
> +free_opt:
> + if (*mnt_opts) {
> + selinux_free_mnt_opts(*mnt_opts);
> + *mnt_opts = NULL;
> + }
> + return rc;
> }
>
> static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
--
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.
