From: Sascha Hauer <s.hauer@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: barebox@lists.infradead.org, Holger Assmann <has@pengutronix.de>
Subject: Re: [PATCH master v2] nv: fix use-after-free when clearing from shell
Date: Fri, 13 Nov 2020 08:37:18 +0100 [thread overview]
Message-ID: <20201113073718.GP29830@pengutronix.de> (raw)
In-Reply-To: <20201112172524.1293-1-a.fatoum@pengutronix.de>
On Thu, Nov 12, 2020 at 06:25:24PM +0100, Ahmad Fatoum wrote:
> When we use hush to set the same nv.var twice to the empty string:
>
> $ nv.user=
> $ nv.user=
>
> nv_set is called twice with a NULL val argument leading
> to a double free and accompanied memory corruption.
>
> Reorder the code, so p->value is freed just once.
>
> Fixes: fa4c41ba60af ("nvvar: when setting a nvvar to NULL just free the content")
> Cc: Holger Assmann <has@pengutronix.de>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v1 -> v2:
> Use correct author email in DCO
> ---
> common/globalvar.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
Took this one instead of v1
Sascha
>
> diff --git a/common/globalvar.c b/common/globalvar.c
> index 60793d7a30c6..a55b38b00fd5 100644
> --- a/common/globalvar.c
> +++ b/common/globalvar.c
> @@ -179,16 +179,12 @@ static int nv_set(struct device_d *dev, struct param_d *p, const char *name, con
> {
> int ret;
>
> - if (!val) {
> - if (p)
> - free(p->value);
> - return 0;
> + if (val) {
> + ret = dev_set_param(&global_device, name, val);
> + if (ret)
> + return ret;
> }
>
> - ret = dev_set_param(&global_device, name, val);
> - if (ret)
> - return ret;
> -
> if (p) {
> free(p->value);
> p->value = xstrdup(val);
> --
> 2.28.0
>
>
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prev parent reply other threads:[~2020-11-13 7:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 17:25 Ahmad Fatoum
2020-11-13 7:37 ` Sascha Hauer [this message]
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