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From: <gregkh@linuxfoundation.org>
To: zhengjun.xing@linux.intel.com, gregkh@linuxfoundation.org,
	mathias.nyman@linux.intel.com, stable@vger.kernel.org
Cc: <stable@vger.kernel.org>, <stable-commits@vger.kernel.org>
Subject: Patch "xhci: Fix NULL pointer in xhci debugfs" has been added to the 4.15-stable tree
Date: Fri, 23 Feb 2018 10:52:00 +0100	[thread overview]
Message-ID: <15193795208857@kroah.com> (raw)


This is a note to let you know that I've just added the patch titled

    xhci: Fix NULL pointer in xhci debugfs

to the 4.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xhci-fix-null-pointer-in-xhci-debugfs.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From fa2dfd0ec22e0069c84dfae162972cbbc7c75488 Mon Sep 17 00:00:00 2001
From: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Date: Mon, 12 Feb 2018 14:24:48 +0200
Subject: xhci: Fix NULL pointer in xhci debugfs

From: Zhengjun Xing <zhengjun.xing@linux.intel.com>

commit fa2dfd0ec22e0069c84dfae162972cbbc7c75488 upstream.

Commit dde634057da7 ("xhci: Fix use-after-free in xhci debugfs") causes a
null pointer dereference while fixing xhci-debugfs usage of ring pointers
that were freed during hibernate.

The fix passed addresses to ring pointers instead, but forgot to do this
change for the xhci_ring_trb_show function.

The address of the ring pointer passed to xhci-debugfs was of a temporary
ring pointer "new_ring" instead of the actual ring "ring" pointer. The
temporary new_ring pointer will be set to NULL later causing the NULL
pointer dereference.

This issue was seen when reading xhci related files in debugfs:

cat /sys/kernel/debug/usb/xhci/*/devices/*/ep*/trbs

[  184.604861] BUG: unable to handle kernel NULL pointer dereference at (null)
[  184.613776] IP: xhci_ring_trb_show+0x3a/0x890
[  184.618733] PGD 264193067 P4D 264193067 PUD 263238067 PMD 0
[  184.625184] Oops: 0000 [#1] SMP
[  184.726410] RIP: 0010:xhci_ring_trb_show+0x3a/0x890
[  184.731944] RSP: 0018:ffffba8243c0fd90 EFLAGS: 00010246
[  184.737880] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000000295d6
[  184.746020] RDX: 00000000000295d5 RSI: 0000000000000001 RDI: ffff971a6418d400
[  184.754121] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  184.762222] R10: ffff971a64c98a80 R11: ffff971a62a00e40 R12: ffff971a62a85500
[  184.770325] R13: 0000000000020000 R14: ffff971a6418d400 R15: ffff971a6418d400
[  184.778448] FS:  00007fe725a79700(0000) GS:ffff971a6ec00000(0000) knlGS:0000000000000000
[  184.787644] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  184.794168] CR2: 0000000000000000 CR3: 000000025f365005 CR4: 00000000003606f0
[  184.802318] Call Trace:
[  184.805094]  ? seq_read+0x281/0x3b0
[  184.809068]  seq_read+0xeb/0x3b0
[  184.812735]  full_proxy_read+0x4d/0x70
[  184.817007]  __vfs_read+0x23/0x120
[  184.820870]  vfs_read+0x91/0x130
[  184.824538]  SyS_read+0x42/0x90
[  184.828106]  entry_SYSCALL_64_fastpath+0x1a/0x7d

Fixes: dde634057da7 ("xhci: Fix use-after-free in xhci debugfs")
Cc: <stable@vger.kernel.org> # v4.15
Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/xhci-debugfs.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/host/xhci-debugfs.c
+++ b/drivers/usb/host/xhci-debugfs.c
@@ -211,7 +211,7 @@ static void xhci_ring_dump_segment(struc
 static int xhci_ring_trb_show(struct seq_file *s, void *unused)
 {
 	int			i;
-	struct xhci_ring	*ring = s->private;
+	struct xhci_ring	*ring = *(struct xhci_ring **)s->private;
 	struct xhci_segment	*seg = ring->first_seg;
 
 	for (i = 0; i < ring->num_segs; i++) {
@@ -387,7 +387,7 @@ void xhci_debugfs_create_endpoint(struct
 
 	snprintf(epriv->name, sizeof(epriv->name), "ep%02d", ep_index);
 	epriv->root = xhci_debugfs_create_ring_dir(xhci,
-						   &dev->eps[ep_index].new_ring,
+						   &dev->eps[ep_index].ring,
 						   epriv->name,
 						   spriv->root);
 	spriv->eps[ep_index] = epriv;


Patches currently in stable-queue which might be from zhengjun.xing@linux.intel.com are

queue-4.15/xhci-fix-xhci-debugfs-devices-node-disappearance-after-hibernation.patch
queue-4.15/xhci-fix-xhci-debugfs-errors-in-xhci_stop.patch
queue-4.15/xhci-xhci-debugfs-device-nodes-weren-t-removed-after-device-plugged-out.patch
queue-4.15/xhci-fix-null-pointer-in-xhci-debugfs.patch

                 reply	other threads:[~2018-02-23  9:52 UTC|newest]

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