On Thu, Feb 26, 2009 at 06:27:04PM -0800, Bob Copeland wrote: > On Fri, Feb 27, 2009 at 12:32:55AM +0100, Jiri Slaby wrote: > > On 27.2.2009 00:28, Bob Copeland wrote: > >> hw_to_driver_rix() returns sc->rate_idx[x][y] as an int, and that > >> array is initialized to (u8)-1 for invalid rates. So, it can > >> return 255 if the hardware rate index (y) is bad, then the check > >> "rxs.rate_idx>= 0" would always be true, right? If it's not a > >> real bug yet, it likely will be one day :) > > > > Ah, yes, it really is a bug(tm), care to post a fix? > > Actually, I remembered in the dark recesses of my moldering brain > that someone had a lost patch for this a while ago, so I searched > the archives. Pavel, ok to add your s-o-b? > > From: Pavel Roskin <[email protected]> > Subject: [PATCH] ath5k: use signed elements for rate index table > > A lookup table is used to convert from hardware rate indexes back > to driver-based rate indexes. For unknown hardware rates, we > initialize these values to -1, but since the array elements are of > type u8, they will be in the range 0-255. This can cause array > overruns because subsequent sanity checks only check for negative > values. > > Signed-off-by: Bob Copeland <[email protected]> > --- > drivers/net/wireless/ath5k/base.h | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/net/wireless/ath5k/base.h > b/drivers/net/wireless/ath5k/base.h > index 20e0d14..8229561 100644 > --- a/drivers/net/wireless/ath5k/base.h > +++ b/drivers/net/wireless/ath5k/base.h > @@ -112,7 +112,7 @@ struct ath5k_softc { > struct ieee80211_supported_band sbands[IEEE80211_NUM_BANDS]; > struct ieee80211_channel channels[ATH_CHAN_MAX]; > struct ieee80211_rate rates[IEEE80211_NUM_BANDS][AR5K_MAX_RATES]; > - u8 rate_idx[IEEE80211_NUM_BANDS][AR5K_MAX_RATES]; > + s8 rate_idx[IEEE80211_NUM_BANDS][AR5K_MAX_RATES];
Might be worth adding a note why this is the case. Can't we simply avoid this by checking earlier for the error or simply assigning it an actual default _good_ hw rate value? Luis _______________________________________________ ath5k-devel mailing list [email protected] https://lists.ath5k.org/mailman/listinfo/ath5k-devel
