From 621ad7c96aa138cfeab53cd4debc5a4e08b2189b Mon Sep 17 00:00:00 2001 From: "John W. Linville" Date: Tue, 5 May 2009 15:18:26 -0400 Subject: [PATCH] mac80211: avoid NULL ptr deref when finding max_rates in PID and minstrel "There is another problem with this piece of code. The sband will be NULL after second iteration on single band device and cause null pointer dereference. Everything is working with dual band card. Sorry, but i don't know how to explain this clearly in English. I have looked on the second patch for pid algorithm and found similar bug." Reported-by: Karol Szuster Signed-off-by: John W. Linville --- net/mac80211/rc80211_minstrel.c | 2 +- net/mac80211/rc80211_pid_algo.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c index 70df3dcc3cf6..d9233ec50610 100644 --- a/net/mac80211/rc80211_minstrel.c +++ b/net/mac80211/rc80211_minstrel.c @@ -477,7 +477,7 @@ minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp) for (i = 0; i < IEEE80211_NUM_BANDS; i++) { sband = hw->wiphy->bands[i]; - if (sband->n_bitrates > max_rates) + if (sband && sband->n_bitrates > max_rates) max_rates = sband->n_bitrates; } diff --git a/net/mac80211/rc80211_pid_algo.c b/net/mac80211/rc80211_pid_algo.c index 01d59a8e334c..8bef9a1262ff 100644 --- a/net/mac80211/rc80211_pid_algo.c +++ b/net/mac80211/rc80211_pid_algo.c @@ -378,7 +378,7 @@ static void *rate_control_pid_alloc(struct ieee80211_hw *hw, for (i = 0; i < IEEE80211_NUM_BANDS; i++) { sband = hw->wiphy->bands[i]; - if (sband->n_bitrates > max_rates) + if (sband && sband->n_bitrates > max_rates) max_rates = sband->n_bitrates; }