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[PATCH] wifi: iwlegacy: Check rate_idx range after addition

Stanislaw Gruszka posted 1 patch 7 months ago
There is a newer version of this series
drivers/net/wireless/intel/iwlegacy/4965-mac.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
[PATCH] wifi: iwlegacy: Check rate_idx range after addition
Posted by Stanislaw Gruszka 7 months ago 
Move rate_idx range check after we add IL_FIRST_OFDM_RATE for it
for 5GHz band.

Additionally use ">= RATE_COUNT" check instead of "> RATE_COUNT_LEGACY"
to avoid possible reviewers and static code analyzers confusion about
size of il_rate array.

Reported-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reported-by: Alexei Safin <a.safin@rosa.ru>
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
---
 drivers/net/wireless/intel/iwlegacy/4965-mac.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
index dc8c408902e6..2294ea43b4c7 100644
--- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
+++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
@@ -1567,16 +1567,19 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
 	/**
 	 * If the current TX rate stored in mac80211 has the MCS bit set, it's
 	 * not really a TX rate.  Thus, we use the lowest supported rate for
-	 * this band.  Also use the lowest supported rate if the stored rate
-	 * idx is invalid.
+	 * this band.
 	 */
 	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)
+	if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
 		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)
+	else if (info->band == NL80211_BAND_5GHZ)
+		/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
 		rate_idx += IL_FIRST_OFDM_RATE;
+
+	/* Use the lowest supported rate if the stored rate idx is invalid. */
+	if (rate_idx < 0 || rate_idx >= RATE_COUNT)
+		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
+
 	/* Get PLCP rate for tx_cmd->rate_n_flags */
 	rate_plcp = il_rates[rate_idx].plcp;
 	/* Zero out flags for this packet */
-- 
2.25.4
Re: [PATCH] wifi: iwlegacy: Check rate_idx range after addition
Posted by Fedor Pchelkin 7 months ago 
On Sat, 17. May 09:40, Stanislaw Gruszka wrote:
> Move rate_idx range check after we add IL_FIRST_OFDM_RATE for it
> for 5GHz band.
> 
> Additionally use ">= RATE_COUNT" check instead of "> RATE_COUNT_LEGACY"
> to avoid possible reviewers and static code analyzers confusion about
> size of il_rate array.
> 
> Reported-by: Fedor Pchelkin <pchelkin@ispras.ru>
> Reported-by: Alexei Safin <a.safin@rosa.ru>
> Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
> ---

Thank you for the patch, Stanislaw!

Please see some comments below.

>  drivers/net/wireless/intel/iwlegacy/4965-mac.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> index dc8c408902e6..2294ea43b4c7 100644
> --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> @@ -1567,16 +1567,19 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
>  	/**
>  	 * If the current TX rate stored in mac80211 has the MCS bit set, it's
>  	 * not really a TX rate.  Thus, we use the lowest supported rate for
> -	 * this band.  Also use the lowest supported rate if the stored rate
> -	 * idx is invalid.
> +	 * this band.
>  	 */
>  	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)
> +	if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
>  		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)
> +	else if (info->band == NL80211_BAND_5GHZ)

5GHZ shouldn't be in 'else if' clause, I think. Is it mutually exclusive
with IEEE80211_TX_RC_MCS ?

> +		/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
>  		rate_idx += IL_FIRST_OFDM_RATE;
> +
> +	/* Use the lowest supported rate if the stored rate idx is invalid. */
> +	if (rate_idx < 0 || rate_idx >= RATE_COUNT)

There is a check inside il4965_rs_get_rate():

	/* Check for invalid rates */
	if (rate_idx < 0 || rate_idx >= RATE_COUNT_LEGACY ||
	    (sband->band == NL80211_BAND_5GHZ &&
	     rate_idx < IL_FIRST_OFDM_RATE))
		rate_idx = rate_lowest_index(sband, sta);

so RATE_COUNT_LEGACY (60M) is considered invalid there but is accepted
here in il4965_tx_cmd_build_rate(). It looks strange, at least for the
fresh reader as me..

> +		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
> +
>  	/* Get PLCP rate for tx_cmd->rate_n_flags */
>  	rate_plcp = il_rates[rate_idx].plcp;
>  	/* Zero out flags for this packet */
> -- 
> 2.25.4
Re: [PATCH] wifi: iwlegacy: Check rate_idx range after addition
Posted by Stanislaw Gruszka 7 months ago 
Hi Fedor, thanks for review,

On Sat, May 17, 2025 at 03:21:03PM +0300, Fedor Pchelkin wrote:
> On Sat, 17. May 09:40, Stanislaw Gruszka wrote:
> > Move rate_idx range check after we add IL_FIRST_OFDM_RATE for it
> > for 5GHz band.
> > 
> > Additionally use ">= RATE_COUNT" check instead of "> RATE_COUNT_LEGACY"
> > to avoid possible reviewers and static code analyzers confusion about
> > size of il_rate array.
> > 
> > Reported-by: Fedor Pchelkin <pchelkin@ispras.ru>
> > Reported-by: Alexei Safin <a.safin@rosa.ru>
> > Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
> > ---
> 
> Thank you for the patch, Stanislaw!
> 
> Please see some comments below.
> 
> >  drivers/net/wireless/intel/iwlegacy/4965-mac.c | 15 +++++++++------
> >  1 file changed, 9 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > index dc8c408902e6..2294ea43b4c7 100644
> > --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> > @@ -1567,16 +1567,19 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
> >  	/**
> >  	 * If the current TX rate stored in mac80211 has the MCS bit set, it's
> >  	 * not really a TX rate.  Thus, we use the lowest supported rate for
> > -	 * this band.  Also use the lowest supported rate if the stored rate
> > -	 * idx is invalid.
> > +	 * this band.
> >  	 */
> >  	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)
> > +	if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
> >  		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)
> > +	else if (info->band == NL80211_BAND_5GHZ)
> 
> 5GHZ shouldn't be in 'else if' clause, I think. Is it mutually exclusive
> with IEEE80211_TX_RC_MCS ?

Right, this is wrong. I thought we can use index returned by
rate_lowest_index() but we still should add IL_FIRST_OFDM_RATE.
At least this is how is done now.

> 
> > +		/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
> >  		rate_idx += IL_FIRST_OFDM_RATE;
> > +
> > +	/* Use the lowest supported rate if the stored rate idx is invalid. */
> > +	if (rate_idx < 0 || rate_idx >= RATE_COUNT)
> 
> There is a check inside il4965_rs_get_rate():
> 
> 	/* Check for invalid rates */
> 	if (rate_idx < 0 || rate_idx >= RATE_COUNT_LEGACY ||
> 	    (sband->band == NL80211_BAND_5GHZ &&
> 	     rate_idx < IL_FIRST_OFDM_RATE))
> 		rate_idx = rate_lowest_index(sband, sta);
> 
> so RATE_COUNT_LEGACY (60M) is considered invalid there but is accepted
> here in il4965_tx_cmd_build_rate(). It looks strange, at least for the
> fresh reader as me..

Indeed this is strange. I'm not sure why those checks differ.

Anyway for the rate_idx in il4965_tx_cmd_build_rate()
for 5GHs I'll just add additional check like below:

	if (info->band == NL80211_BAND_5GHZ) {
		rate_idx += IL_FIRST_OFDM_RATE;
		if (rate_idx > IL_LAST_OFDM_RATE);
			rate_idx = IL_LAST_OFDM_RATE;
	}

This patch should be dropped.

Regards
Stanislaw
[PATCH v2] wifi: iwlegacy: Check rate_idx range after addition
Posted by Stanislaw Gruszka 6 months, 4 weeks ago 
Limit rate_idx to IL_LAST_OFDM_RATE for 5GHz band for thinkable case
the index is incorrect.

Reported-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reported-by: Alexei Safin <a.safin@rosa.ru>
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
---
v1 -> v2: 
 - just add check one possible case the index could be incorrect,
   instead of doing broader changes.

 drivers/net/wireless/intel/iwlegacy/4965-mac.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
index dc8c408902e6..4d2148147b94 100644
--- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
+++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
@@ -1575,8 +1575,11 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
 	    || 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)
+	if (info->band == NL80211_BAND_5GHZ) {
 		rate_idx += IL_FIRST_OFDM_RATE;
+		if (rate_idx > IL_LAST_OFDM_RATE)
+			rate_idx = IL_LAST_OFDM_RATE;
+	}
 	/* Get PLCP rate for tx_cmd->rate_n_flags */
 	rate_plcp = il_rates[rate_idx].plcp;
 	/* Zero out flags for this packet */
-- 
2.25.4
Re: [PATCH v2] wifi: iwlegacy: Check rate_idx range after addition
Posted by Fedor Pchelkin 6 months, 3 weeks ago 
On Sun, 25. May 16:45, Stanislaw Gruszka wrote:
> Limit rate_idx to IL_LAST_OFDM_RATE for 5GHz band for thinkable case
> the index is incorrect.
> 
> Reported-by: Fedor Pchelkin <pchelkin@ispras.ru>
> Reported-by: Alexei Safin <a.safin@rosa.ru>
> Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
> ---
> v1 -> v2: 
>  - just add check one possible case the index could be incorrect,
>    instead of doing broader changes.
> 
>  drivers/net/wireless/intel/iwlegacy/4965-mac.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> index dc8c408902e6..4d2148147b94 100644
> --- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> +++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
> @@ -1575,8 +1575,11 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
>  	    || 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)
> +	if (info->band == NL80211_BAND_5GHZ) {
>  		rate_idx += IL_FIRST_OFDM_RATE;
> +		if (rate_idx > IL_LAST_OFDM_RATE)
> +			rate_idx = IL_LAST_OFDM_RATE;
> +	}
>  	/* Get PLCP rate for tx_cmd->rate_n_flags */
>  	rate_plcp = il_rates[rate_idx].plcp;
>  	/* Zero out flags for this packet */
> -- 
> 2.25.4
> 

Thanks, Stanislaw!

To my mind, it looks reasonable. FWIW,

Reviewed-by: Fedor Pchelkin <pchelkin@ispras.ru>

Patchew 2.1-devel-b67e4c2

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