[PATCH AUTOSEL 4.4 3/8] mac80211: fix double free in ibss_leave

[PATCH AUTOSEL 4.4 3/8] mac80211: fix double free in ibss_leave

[Sasha Levin]

From: Markus Theil <markus.theil@tu-ilmenau.de>

[ Upstream commit 3bd801b14e0c5d29eeddc7336558beb3344efaa3 ]

Clear beacon ie pointer and ie length after free
in order to prevent double free.

==================================================================
BUG: KASAN: double-free or invalid-free \
in ieee80211_ibss_leave+0x83/0xe0 net/mac80211/ibss.c:1876

CPU: 0 PID: 8472 Comm: syz-executor100 Not tainted 5.11.0-rc6-syzkaller #0
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2c6 mm/kasan/report.c:230
 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:355
 ____kasan_slab_free+0xcc/0xe0 mm/kasan/common.c:341
 kasan_slab_free include/linux/kasan.h:192 [inline]
 __cache_free mm/slab.c:3424 [inline]
 kfree+0xed/0x270 mm/slab.c:3760
 ieee80211_ibss_leave+0x83/0xe0 net/mac80211/ibss.c:1876
 rdev_leave_ibss net/wireless/rdev-ops.h:545 [inline]
 __cfg80211_leave_ibss+0x19a/0x4c0 net/wireless/ibss.c:212
 __cfg80211_leave+0x327/0x430 net/wireless/core.c:1172
 cfg80211_leave net/wireless/core.c:1221 [inline]
 cfg80211_netdev_notifier_call+0x9e8/0x12c0 net/wireless/core.c:1335
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2040
 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
 call_netdevice_notifiers net/core/dev.c:2066 [inline]
 __dev_close_many+0xee/0x2e0 net/core/dev.c:1586
 __dev_close net/core/dev.c:1624 [inline]
 __dev_change_flags+0x2cb/0x730 net/core/dev.c:8476
 dev_change_flags+0x8a/0x160 net/core/dev.c:8549
 dev_ifsioc+0x210/0xa70 net/core/dev_ioctl.c:265
 dev_ioctl+0x1b1/0xc40 net/core/dev_ioctl.c:511
 sock_do_ioctl+0x148/0x2d0 net/socket.c:1060
 sock_ioctl+0x477/0x6a0 net/socket.c:1177
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported-by: syzbot+93976391bf299d425f44@syzkaller.appspotmail.com
Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
Link: https://lore.kernel.org/r/20210213133653.367130-1-markus.theil@tu-ilmenau.de
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/ibss.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index f2af19673b26..50fa92fe7d24 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -1860,6 +1860,8 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 
 	/* remove beacon */
 	kfree(sdata->u.ibss.ie);
+	sdata->u.ibss.ie = NULL;
+	sdata->u.ibss.ie_len = 0;
 
 	/* on the next join, re-program HT parameters */
 	memset(&ifibss->ht_capa, 0, sizeof(ifibss->ht_capa));
-- 
2.30.1

[PATCH AUTOSEL 4.4 4/8] mac80211: choose first enabled channel for monitor

[Sasha Levin]

From: Karthikeyan Kathirvel <kathirve@codeaurora.org>

[ Upstream commit 041c881a0ba8a75f71118bd9766b78f04beed469 ]

Even if the first channel from sband channel list is invalid
or disabled mac80211 ends up choosing it as the default channel
for monitor interfaces, making them not usable.

Fix this by assigning the first available valid or enabled
channel instead.

Signed-off-by: Karthikeyan Kathirvel <kathirve@codeaurora.org>
Link: https://lore.kernel.org/r/1615440547-7661-1-git-send-email-kathirve@codeaurora.org
[reword commit message, comment, code cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/main.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 15d23aeea634..2357b17254e7 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -889,8 +889,19 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 			continue;
 
 		if (!dflt_chandef.chan) {
+			/*
+			 * Assign the first enabled channel to dflt_chandef
+			 * from the list of channels
+			 */
+			for (i = 0; i < sband->n_channels; i++)
+				if (!(sband->channels[i].flags &
+						IEEE80211_CHAN_DISABLED))
+					break;
+			/* if none found then use the first anyway */
+			if (i == sband->n_channels)
+				i = 0;
 			cfg80211_chandef_create(&dflt_chandef,
-						&sband->channels[0],
+						&sband->channels[i],
 						NL80211_CHAN_NO_HT);
 			/* init channel we're on */
 			if (!local->use_chanctx && !local->_oper_chandef.chan) {
-- 
2.30.1