diff mbox series

[v2] iwlegacy: 4965: fix possible out-of-bounds access in il4965_tx_cmd_build_rate()

Message ID 20250424185244.3562-1-a.safin@rosa.ru
State Superseded
Headers show
Series [v2] iwlegacy: 4965: fix possible out-of-bounds access in il4965_tx_cmd_build_rate() | expand

Commit Message

Alexei Safin April 24, 2025, 6:52 p.m. UTC
Prevent out-of-bounds access in il4965_tx_cmd_build_rate() by rejecting
rate_idx values greater than or equal to RATE_COUNT_LEGACY.

Use a correct bounds check to avoid accessing il_rates[] with
an invalid index. The previous comparison allowed rate_idx to become
equal to RATE_COUNT_LEGACY, which exceeds the array limit.

Replace the check 'rate_idx > RATE_COUNT_LEGACY' with
'rate_idx >= RATE_COUNT_LEGACY' to ensure memory safety.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 7ac9a364c172 ("iwlegacy: move under intel directory")
Signed-off-by: Alexei Safin <a.safin@rosa.ru>
---
v2: change reciepent
 drivers/net/wireless/intel/iwlegacy/4965-mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Ping-Ke Shih April 25, 2025, 5:59 a.m. UTC | #1
Alexei Safin <a.safin@rosa.ru> wrote:
> 
> Prevent out-of-bounds access in il4965_tx_cmd_build_rate() by rejecting
> rate_idx values greater than or equal to RATE_COUNT_LEGACY.
> 
> Use a correct bounds check to avoid accessing il_rates[] with
> an invalid index. The previous comparison allowed rate_idx to become
> equal to RATE_COUNT_LEGACY, which exceeds the array limit.
> 
> Replace the check 'rate_idx > RATE_COUNT_LEGACY' with
> 'rate_idx >= RATE_COUNT_LEGACY' to ensure memory safety.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 7ac9a364c172 ("iwlegacy: move under intel directory")

The Fixes is obviously wrong. It just moved the code. 

> Signed-off-by: Alexei Safin <a.safin@rosa.ru>
> ---
> v2: change reciepent
>  drivers/net/wireless/intel/iwlegacy/4965-mac.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> index 78dee8ccfebf..f60d9b9798c1 100644
> --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> @@ -1572,7 +1572,7 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
>          */
>         rate_idx = info->control.rates[0].idx;
>         if ((info->control.rates[0].flags & IEEE80211_TX_RC_MCS) || rate_idx < 0
> -           || rate_idx > RATE_COUNT_LEGACY)
> +           || rate_idx >= RATE_COUNT_LEGACY)
>                 rate_idx = rate_lowest_index(&il->bands[info->band], sta);
>         /* For 5 GHZ band, remap mac80211 rate indices into driver indices */
>         if (info->band == NL80211_BAND_5GHZ)
> --
> 2.39.5 (Apple Git-154)
>
Stanislaw Gruszka April 27, 2025, 6:39 a.m. UTC | #2
Hi

On Thu, Apr 24, 2025 at 09:52:44PM +0300, Alexei Safin wrote:
> Prevent out-of-bounds access in il4965_tx_cmd_build_rate() by rejecting
> rate_idx values greater than or equal to RATE_COUNT_LEGACY.
> 
> Use a correct bounds check to avoid accessing il_rates[] with
> an invalid index. The previous comparison allowed rate_idx to become
> equal to RATE_COUNT_LEGACY, which exceeds the array limit.

Thanks for the patch, however I think it's not correct.

The definitions are:

enum {
        RATE_1M_IDX = 0,
	...
	RATE_54M_INDEX,
	RATE_60M_INDEX,
	RATE_COUNT
        RATE_COUNT_LEGACY = RATE_COUNT - 1,     /* Excluding 60M */
}

extern const struct il_rate_info il_rates[RATE_COUNT];

> Replace the check 'rate_idx > RATE_COUNT_LEGACY' with
> 'rate_idx >= RATE_COUNT_LEGACY' to ensure memory safety.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.

> Fixes: 7ac9a364c172 ("iwlegacy: move under intel directory")
> Signed-off-by: Alexei Safin <a.safin@rosa.ru>
> ---
> v2: change reciepent
>  drivers/net/wireless/intel/iwlegacy/4965-mac.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> index 78dee8ccfebf..f60d9b9798c1 100644
> --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> @@ -1572,7 +1572,7 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
>  	 */
>  	rate_idx = info->control.rates[0].idx;
>  	if ((info->control.rates[0].flags & IEEE80211_TX_RC_MCS) || rate_idx < 0
> -	    || rate_idx > RATE_COUNT_LEGACY)
> +	    || rate_idx >= RATE_COUNT_LEGACY)
>  		rate_idx = rate_lowest_index(&il->bands[info->band], sta);

.. so looks the check is fine already and changing it will induce a bug
for RATE_54M_INDEX.

Regards
Stanislaw

>  	/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
>  	if (info->band == NL80211_BAND_5GHZ)
> -- 
> 2.39.5 (Apple Git-154)
>
Fedor Pchelkin April 29, 2025, 5:15 p.m. UTC | #3
Hello,

On Sun, 27. Apr 08:39, Stanislaw Gruszka wrote:
> > diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > index 78dee8ccfebf..f60d9b9798c1 100644
> > --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > @@ -1572,7 +1572,7 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
> >  	 */
> >  	rate_idx = info->control.rates[0].idx;
> >  	if ((info->control.rates[0].flags & IEEE80211_TX_RC_MCS) || rate_idx < 0
> > -	    || rate_idx > RATE_COUNT_LEGACY)
> > +	    || rate_idx >= RATE_COUNT_LEGACY)
> >  		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
> 
> .. so looks the check is fine already and changing it will induce a bug
> for RATE_54M_INDEX.
> 
> Regards
> Stanislaw
> 
> >  	/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
> >  	if (info->band == NL80211_BAND_5GHZ)

Here goes the fragment:

		rate_idx += IL_FIRST_OFDM_RATE;
	/* Get PLCP rate for tx_cmd->rate_n_flags */
	rate_plcp = il_rates[rate_idx].plcp;

> > -- 
> > 2.39.5 (Apple Git-154)
> > 

Looks like the proper checks should be added to address the 5GHZ case and
validate that the index won't exceed the array boundaries after being shifted
by IL_FIRST_OFDM_RATE.

--
Thanks,
Fedor
Stanislaw Gruszka April 29, 2025, 9:40 p.m. UTC | #4
Hi

On Tue, Apr 29, 2025 at 08:15:59PM +0300, Fedor Pchelkin wrote:
> Hello,
> 
> On Sun, 27. Apr 08:39, Stanislaw Gruszka wrote:
> > > diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > > index 78dee8ccfebf..f60d9b9798c1 100644
> > > --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > > +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > > @@ -1572,7 +1572,7 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
> > >  	 */
> > >  	rate_idx = info->control.rates[0].idx;
> > >  	if ((info->control.rates[0].flags & IEEE80211_TX_RC_MCS) || rate_idx < 0
> > > -	    || rate_idx > RATE_COUNT_LEGACY)
> > > +	    || rate_idx >= RATE_COUNT_LEGACY)
> > >  		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
> > 
> > .. so looks the check is fine already and changing it will induce a bug
> > for RATE_54M_INDEX.
> > 
> > Regards
> > Stanislaw
> > 
> > >  	/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
> > >  	if (info->band == NL80211_BAND_5GHZ)
> 
> Here goes the fragment:
> 
> 		rate_idx += IL_FIRST_OFDM_RATE;
> 	/* Get PLCP rate for tx_cmd->rate_n_flags */
> 	rate_plcp = il_rates[rate_idx].plcp;
> 
> > > -- 
> > > 2.39.5 (Apple Git-154)
> > > 
> 
> Looks like the proper checks should be added to address the 5GHZ case and
> validate that the index won't exceed the array boundaries after being shifted
> by IL_FIRST_OFDM_RATE.

Good point. It make sense to move rate_idx range check after possible
IL_FIRST_OFDM_RATE addition for 5GHz.

Regards
Stanislaw
diff mbox series

Patch

diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
index 78dee8ccfebf..f60d9b9798c1 100644
--- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
+++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
@@ -1572,7 +1572,7 @@  il4965_tx_cmd_build_rate(struct il_priv *il,
 	 */
 	rate_idx = info->control.rates[0].idx;
 	if ((info->control.rates[0].flags & IEEE80211_TX_RC_MCS) || rate_idx < 0
-	    || rate_idx > RATE_COUNT_LEGACY)
+	    || rate_idx >= RATE_COUNT_LEGACY)
 		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
 	/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
 	if (info->band == NL80211_BAND_5GHZ)