Linux-Wireless Archive on lore.kernel.org
 help / color / Atom feed
From: "Pali Rohár" <pali@kernel.org>
To: "Amitkumar Karwar" <amitkarwar@gmail.com>,
	"Ganapathi Bhat" <ganapathi.bhat@nxp.com>,
	"Xinming Hu" <huxinming820@gmail.com>,
	"Kalle Valo" <kvalo@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	"Cathy Luo" <cluo@marvell.com>,
	"Avinash Patil" <patila@marvell.com>,
	"Marek Behún" <marek.behun@nic.cz>
Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] mwifiex: Fix memory corruption in dump_station
Date: Fri, 15 May 2020 09:59:24 +0200
Message-ID: <20200515075924.13841-1-pali@kernel.org> (raw)

The mwifiex_cfg80211_dump_station() uses static variable for iterating
over a linked list of all associated stations (when the driver is in UAP
role). This has a race condition if .dump_station is called in parallel
for multiple interfaces. This corruption can be triggered by registering
multiple SSIDs and calling, in parallel for multiple interfaces
    iw dev <iface> station dump

[16750.719775] Unable to handle kernel paging request at virtual address dead000000000110
...
[16750.899173] Call trace:
[16750.901696]  mwifiex_cfg80211_dump_station+0x94/0x100 [mwifiex]
[16750.907824]  nl80211_dump_station+0xbc/0x278 [cfg80211]
[16750.913160]  netlink_dump+0xe8/0x320
[16750.916827]  netlink_recvmsg+0x1b4/0x338
[16750.920861]  ____sys_recvmsg+0x7c/0x2b0
[16750.924801]  ___sys_recvmsg+0x70/0x98
[16750.928564]  __sys_recvmsg+0x58/0xa0
[16750.932238]  __arm64_sys_recvmsg+0x28/0x30
[16750.936453]  el0_svc_common.constprop.3+0x90/0x158
[16750.941378]  do_el0_svc+0x74/0x90
[16750.944784]  el0_sync_handler+0x12c/0x1a8
[16750.948903]  el0_sync+0x114/0x140
[16750.952312] Code: f9400003 f907f423 eb02007f 54fffd60 (b9401060)
[16750.958583] ---[ end trace c8ad181c2f4b8576 ]---

This patch drops the use of the static iterator, and instead every time
the function is called iterates to the idx-th position of the
linked-list.

It would be better to convert the code not to use linked list for
associated stations storage (since the chip has a limited number of
associated stations anyway - it could just be an array). Such a change
may be proposed in the future. In the meantime this patch can backported
into stable kernels in this simple form.

Fixes: 8baca1a34d4c ("mwifiex: dump station support in uap mode")
Signed-off-by: Pali Rohár <pali@kernel.org>
---
 drivers/net/wireless/marvell/mwifiex/cfg80211.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 1566d2197906..12bfd653a405 100644
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -1496,7 +1496,8 @@ mwifiex_cfg80211_dump_station(struct wiphy *wiphy, struct net_device *dev,
 			      int idx, u8 *mac, struct station_info *sinfo)
 {
 	struct mwifiex_private *priv = mwifiex_netdev_get_priv(dev);
-	static struct mwifiex_sta_node *node;
+	struct mwifiex_sta_node *node;
+	int i;
 
 	if ((GET_BSS_ROLE(priv) == MWIFIEX_BSS_ROLE_STA) &&
 	    priv->media_connected && idx == 0) {
@@ -1506,13 +1507,10 @@ mwifiex_cfg80211_dump_station(struct wiphy *wiphy, struct net_device *dev,
 		mwifiex_send_cmd(priv, HOST_CMD_APCMD_STA_LIST,
 				 HostCmd_ACT_GEN_GET, 0, NULL, true);
 
-		if (node && (&node->list == &priv->sta_list)) {
-			node = NULL;
-			return -ENOENT;
-		}
-
-		node = list_prepare_entry(node, &priv->sta_list, list);
-		list_for_each_entry_continue(node, &priv->sta_list, list) {
+		i = 0;
+		list_for_each_entry(node, &priv->sta_list, list) {
+			if (i++ != idx)
+				continue;
 			ether_addr_copy(mac, node->mac_addr);
 			return mwifiex_dump_station_info(priv, node, sinfo);
 		}
-- 
2.20.1


             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15  7:59 Pali Rohár [this message]
2020-05-16  8:07 ` [EXT] " Ganapathi Bhat
2020-05-18 12:19 ` Kalle Valo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200515075924.13841-1-pali@kernel.org \
    --to=pali@kernel.org \
    --cc=amitkarwar@gmail.com \
    --cc=cluo@marvell.com \
    --cc=davem@davemloft.net \
    --cc=ganapathi.bhat@nxp.com \
    --cc=huxinming820@gmail.com \
    --cc=kvalo@codeaurora.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=marek.behun@nic.cz \
    --cc=netdev@vger.kernel.org \
    --cc=patila@marvell.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Wireless Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-wireless/0 linux-wireless/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-wireless linux-wireless/ https://lore.kernel.org/linux-wireless \
		linux-wireless@vger.kernel.org
	public-inbox-index linux-wireless

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-wireless


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git