5.4-stable patches

added patches:
	hamradio-defer-6pack-kfree-after-unregister_netdev.patch
	hamradio-remove-needs_free_netdev-to-avoid-uaf.patch

diff --git a/queue-5.4/hamradio-defer-6pack-kfree-after-unregister_netdev.patch b/queue-5.4/hamradio-defer-6pack-kfree-after-unregister_netdev.patch
new file mode 100644 (file)
index 0000000..7847887
--- /dev/null
+++ b/queue-5.4/hamradio-defer-6pack-kfree-after-unregister_netdev.patch
@@ -0,0 +1,51 @@
+From 0b9111922b1f399aba6ed1e1b8f2079c3da1aed8 Mon Sep 17 00:00:00 2001
+From: Lin Ma <linma@zju.edu.cn>
+Date: Mon, 8 Nov 2021 18:37:59 +0800
+Subject: hamradio: defer 6pack kfree after unregister_netdev
+
+From: Lin Ma <linma@zju.edu.cn>
+
+commit 0b9111922b1f399aba6ed1e1b8f2079c3da1aed8 upstream.
+
+There is a possible race condition (use-after-free) like below
+
+ (USE)                       |  (FREE)
+  dev_queue_xmit             |
+   __dev_queue_xmit          |
+    __dev_xmit_skb           |
+     sch_direct_xmit         | ...
+      xmit_one               |
+       netdev_start_xmit     | tty_ldisc_kill
+        __netdev_start_xmit  |  6pack_close
+         sp_xmit             |   kfree
+          sp_encaps          |
+                             |
+
+According to the patch "defer ax25 kfree after unregister_netdev", this
+patch reorder the kfree after the unregister_netdev to avoid the possible
+UAF as the unregister_netdev() is well synchronized and won't return if
+there is a running routine.
+
+Signed-off-by: Lin Ma <linma@zju.edu.cn>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/net/hamradio/6pack.c |    4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+--- a/drivers/net/hamradio/6pack.c
++++ b/drivers/net/hamradio/6pack.c
+@@ -679,9 +679,11 @@ static void sixpack_close(struct tty_str
+       del_timer_sync(&sp->tx_t);
+       del_timer_sync(&sp->resync_t);
+ 
+-      /* Free all 6pack frame buffers. */
++      /* Free all 6pack frame buffers after unreg. */
+       kfree(sp->rbuff);
+       kfree(sp->xbuff);
++
++      free_netdev(sp->dev);
+ }
+ 
+ /* Perform I/O control on an active 6pack channel. */

diff --git a/queue-5.4/hamradio-remove-needs_free_netdev-to-avoid-uaf.patch b/queue-5.4/hamradio-remove-needs_free_netdev-to-avoid-uaf.patch
new file mode 100644 (file)
index 0000000..cf07c60
--- /dev/null
+++ b/queue-5.4/hamradio-remove-needs_free_netdev-to-avoid-uaf.patch
@@ -0,0 +1,42 @@
+From 81b1d548d00bcd028303c4f3150fa753b9b8aa71 Mon Sep 17 00:00:00 2001
+From: Lin Ma <linma@zju.edu.cn>
+Date: Thu, 11 Nov 2021 22:14:02 +0800
+Subject: hamradio: remove needs_free_netdev to avoid UAF
+
+From: Lin Ma <linma@zju.edu.cn>
+
+commit 81b1d548d00bcd028303c4f3150fa753b9b8aa71 upstream.
+
+The former patch "defer 6pack kfree after unregister_netdev" reorders
+the kfree of two buffer after the unregister_netdev to prevent the race
+condition. It also adds free_netdev() function in sixpack_close(), which
+is a direct copy from the similar code in mkiss_close().
+
+However, in sixpack driver, the flag needs_free_netdev is set to true in
+sp_setup(), hence the unregister_netdev() will free the netdev
+automatically. Therefore, as the sp is netdev_priv, use-after-free
+occurs.
+
+This patch removes the needs_free_netdev = true and just let the
+free_netdev to finish this deallocation task.
+
+Fixes: 0b9111922b1f ("hamradio: defer 6pack kfree after unregister_netdev")
+Signed-off-by: Lin Ma <linma@zju.edu.cn>
+Link: https://lore.kernel.org/r/20211111141402.7551-1-linma@zju.edu.cn
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/net/hamradio/6pack.c |    1 -
+ 1 file changed, 1 deletion(-)
+
+--- a/drivers/net/hamradio/6pack.c
++++ b/drivers/net/hamradio/6pack.c
+@@ -311,7 +311,6 @@ static void sp_setup(struct net_device *
+ {
+       /* Finish setting up the DEVICE info. */
+       dev->netdev_ops         = &sp_netdev_ops;
+-      dev->needs_free_netdev  = true;
+       dev->mtu                = SIXP_MTU;
+       dev->hard_header_len    = AX25_MAX_HEADER_LEN;
+       dev->header_ops         = &ax25_header_ops;

diff --git a/queue-5.4/series b/queue-5.4/series
index b0f4b3db4b95147bf10ee6a550a5330d9fc9b743..3c5217aa29e5324473c2969a7361e32c705d7d85 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -1 +1,3 @@
 floppy-disable-fdrawcmd-by-default.patch
+hamradio-defer-6pack-kfree-after-unregister_netdev.patch
+hamradio-remove-needs_free_netdev-to-avoid-uaf.patch