Return-path: Received: from mail-wi0-f174.google.com ([209.85.212.174]:52497 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753298AbaJQSeZ (ORCPT ); Fri, 17 Oct 2014 14:34:25 -0400 Received: by mail-wi0-f174.google.com with SMTP id h11so3097748wiw.7 for ; Fri, 17 Oct 2014 11:34:24 -0700 (PDT) From: Karl Beldan To: Johannes Berg Cc: Karl Beldan , linux-wireless , karl.beldan@gmail.com, Felix Fietkau Subject: [PATCH] mac80211: minstrels: fix buffer overflow in HT debugfs rc_stats Date: Fri, 17 Oct 2014 20:34:00 +0200 Message-Id: <1413570840-27679-1-git-send-email-karl.beldan@gmail.com> (sfid-20141017_203429_102902_BD3A7D9C) Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Karl Beldan ATM an HT rc_stats line is 106 chars. Times 8(MCS_GROUP_RATES)*3(SS)*2(GI)*2(BW) + CCK(4), i.e. x100, this is well above the current 8192 - sizeof(*ms) currently allocated. Fix this by squeezing the output as follows (not that we're short on memory but this also improves readability and range, the new format adds one more digit to *ok/*cum and ok/cum): - Before (HT) (106 ch): type rate throughput ewma prob this prob retry this succ/attempt success attempts CCK/LP 5.5M 0.0 0.0 0.0 0 0( 0) 0 0 HT20/LGI ABCDP MCS0 0.0 0.0 0.0 1 0( 0) 0 0 - After (75 ch): type rate tpt eprob *prob ret *ok(*cum) ok( cum) CCK/LP 5.5M 0.0 0.0 0.0 0 0( 0) 0( 0) HT20/LGI ABCDP MCS0 0.0 0.0 0.0 1 0( 0) 0( 0) - Align non-HT format Before (non-HT) (83 ch): rate throughput ewma prob this prob this succ/attempt success attempts ABCDP 6 0.0 0.0 0.0 0( 0) 0 0 54 0.0 0.0 0.0 0( 0) 0 0 - After (61 ch): rate tpt eprob *prob *ok(*cum) ok( cum) ABCDP 1 0.0 0.0 0.0 0( 0) 0( 0) 54 0.0 0.0 0.0 0( 0) 0( 0) *This also adds dynamic checks for overflow, lowers the size of the non-HT request (allowing > 30 entries) and replaces the buddy-rounded allocations (s/sizeof(*ms) + 8192/8192). Signed-off-by: Karl Beldan Cc: Felix Fietkau --- Send this one-line patch to stable ? - ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL); + ms = kmalloc(16384, GFP_KERNEL); net/mac80211/rc80211_minstrel_debugfs.c | 12 +++++++----- net/mac80211/rc80211_minstrel_ht_debugfs.c | 13 ++++++++----- 2 files changed, 15 insertions(+), 10 deletions(-) diff --git a/net/mac80211/rc80211_minstrel_debugfs.c b/net/mac80211/rc80211_minstrel_debugfs.c index edde723..b33be0f 100644 --- a/net/mac80211/rc80211_minstrel_debugfs.c +++ b/net/mac80211/rc80211_minstrel_debugfs.c @@ -62,14 +62,14 @@ minstrel_stats_open(struct inode *inode, struct file *file) unsigned int i, tp, prob, eprob; char *p; - ms = kmalloc(sizeof(*ms) + 4096, GFP_KERNEL); + ms = kmalloc(2048, GFP_KERNEL); if (!ms) return -ENOMEM; file->private_data = ms; p = ms->buf; - p += sprintf(p, "rate throughput ewma prob this prob " - "this succ/attempt success attempts\n"); + p += sprintf(p, "rate tpt eprob *prob" + " *ok(*cum) ok( cum)\n"); for (i = 0; i < mi->n_rates; i++) { struct minstrel_rate *mr = &mi->r[i]; struct minstrel_rate_stats *mrs = &mi->r[i].stats; @@ -86,8 +86,8 @@ minstrel_stats_open(struct inode *inode, struct file *file) prob = MINSTREL_TRUNC(mrs->cur_prob * 1000); eprob = MINSTREL_TRUNC(mrs->probability * 1000); - p += sprintf(p, " %6u.%1u %6u.%1u %6u.%1u " - " %3u(%3u) %8llu %8llu\n", + p += sprintf(p, " %4u.%1u %3u.%1u %3u.%1u" + " %4u(%4u) %9llu(%9llu)\n", tp / 10, tp % 10, eprob / 10, eprob % 10, prob / 10, prob % 10, @@ -102,6 +102,8 @@ minstrel_stats_open(struct inode *inode, struct file *file) mi->sample_packets); ms->len = p - ms->buf; + WARN_ON(ms->len > 2048 - sizeof(*ms)); + return 0; } diff --git a/net/mac80211/rc80211_minstrel_ht_debugfs.c b/net/mac80211/rc80211_minstrel_ht_debugfs.c index a72ad46..b51b4ec 100644 --- a/net/mac80211/rc80211_minstrel_ht_debugfs.c +++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c @@ -63,8 +63,8 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p) prob = MINSTREL_TRUNC(mr->cur_prob * 1000); eprob = MINSTREL_TRUNC(mr->probability * 1000); - p += sprintf(p, " %6u.%1u %6u.%1u %6u.%1u " - "%3u %3u(%3u) %8llu %8llu\n", + p += sprintf(p, " %4u.%1u %3u.%1u %3u.%1u " + "%3u %4u(%4u) %9llu(%9llu)\n", tp / 10, tp % 10, eprob / 10, eprob % 10, prob / 10, prob % 10, @@ -96,14 +96,15 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file) return ret; } - ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL); + ms = kmalloc(8192, GFP_KERNEL); if (!ms) return -ENOMEM; file->private_data = ms; p = ms->buf; - p += sprintf(p, "type rate throughput ewma prob " - "this prob retry this succ/attempt success attempts\n"); + p += sprintf(p, "type rate tpt eprob *prob " + "ret *ok(*cum) ok( cum)\n"); + p = minstrel_ht_stats_dump(mi, max_mcs, p); for (i = 0; i < max_mcs; i++) @@ -118,6 +119,8 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file) MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10); ms->len = p - ms->buf; + WARN_ON(ms->len > 8192 - sizeof(*ms)); + return nonseekable_open(inode, file); } -- 2.0.1