Messages in this thread | | | From | Kalle Valo <> | Subject | Re: [PATCH] wl1251: Fix possible buffer overflow in wl1251_cmd_scan | Date | Sun, 18 Apr 2021 09:54:57 +0300 |
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Lee Gibson <leegib@gmail.com> writes:
> Function wl1251_cmd_scan calls memcpy without checking the length. > A user could control that length and trigger a buffer overflow. > Fix by checking the length is within the maximum allowed size. > > Signed-off-by: Lee Gibson <leegib@gmail.com>
Please fix the commit log, the user cannot control this length as cfg80211 checks it before handling it to wl1251. Unless I'm missing something.
> --- > drivers/net/wireless/ti/wl1251/cmd.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/ti/wl1251/cmd.c b/drivers/net/wireless/ti/wl1251/cmd.c > index 498c8db2eb48..e4d028a53d91 100644 > --- a/drivers/net/wireless/ti/wl1251/cmd.c > +++ b/drivers/net/wireless/ti/wl1251/cmd.c > @@ -455,8 +455,11 @@ int wl1251_cmd_scan(struct wl1251 *wl, u8 *ssid, size_t ssid_len, > } > > cmd->params.ssid_len = ssid_len;
If you are checking the length, you should also check ssid_len here.
> - if (ssid) > - memcpy(cmd->params.ssid, ssid, ssid_len); > + if (ssid) { > + int len = min_t(int, ssid_len, IEEE80211_MAX_SSID_LEN); > + > + memcpy(cmd->params.ssid, ssid, len); > + }
Please use clamp_val().
Also another (and IMHO better) way to cleanup this is to provide a pointer to struct cfg80211_ssid, which makes it clear that the length can be trusted and not length checking is not needed. So something like this:
int wl1251_cmd_scan(struct wl1251 *wl, const struct cfg80211_ssid *ssid, struct ieee80211_channel *channels[], unsigned int n_channels, unsigned int n_probes)
-- https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
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