81 lines
3.2 KiB
Diff
81 lines
3.2 KiB
Diff
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From cef7f62d5881e886cd514436bc386a7202af25f1 Mon Sep 17 00:00:00 2001
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From: Nicolai Stange <nicstange@gmail.com>
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Date: Tue, 15 Mar 2016 13:35:06 +0100
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Subject: [PATCH] sound/usb: fix NULL dereference in usb_audio_probe()
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With commit
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aebb2b89bff0 ("[media] sound/usb: Use Media Controller API to share
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media resources")
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an access to quirk->media_device without checking for quirk != NULL has
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been introduced in usb_audio_probe().
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With a Plantronics USB headset (device ID 0x047f:0xc010) attached,
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this results in the following splat at boot time:
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BUG: unable to handle kernel NULL pointer dereference at 0000000000000014
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IP: [<ffffffffa089aa6c>] usb_audio_probe+0x2cc/0x9a0 [snd_usb_audio]
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Oops: 0000 [#1] SMP
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[...]
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CPU: 2 PID: 696 Comm: systemd-udevd Not tainted 4.5.0-next-20160315 #13
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Hardware name: Dell Inc. Latitude E6540/0725FP, BIOS A10 06/26/2014
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task: ffff88021c88d7c0 ti: ffff88003d5b0000 task.ti: ffff88003d5b0000
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RIP: 0010:[<ffffffffa089aa6c>] [<ffffffffa089aa6c>]
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usb_audio_probe+0x2cc/0x9a0 [snd_usb_audio]
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[...]
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Call Trace:
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[<ffffffff815a8e16>] usb_probe_interface+0x136/0x2d0
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[<ffffffff81509edc>] driver_probe_device+0x22c/0x440
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[<ffffffff8150a1c1>] __driver_attach+0xd1/0xf0
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[<ffffffff8150a0f0>] ? driver_probe_device+0x440/0x440
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[<ffffffff815077ec>] bus_for_each_dev+0x6c/0xc0
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[<ffffffff815095ce>] driver_attach+0x1e/0x20
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[<ffffffff81509013>] bus_add_driver+0x1c3/0x280
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[<ffffffff8150ab10>] driver_register+0x60/0xe0
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[<ffffffff815a7711>] usb_register_driver+0x81/0x140
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[<ffffffffa08c7000>] ? 0xffffffffa08c7000
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[<ffffffffa08c701e>] usb_audio_driver_init+0x1e/0x1000 [snd_usb_audio]
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[<ffffffff81002123>] do_one_initcall+0xb3/0x1f0
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[<ffffffff811fb091>] ? __vunmap+0x81/0xd0
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[<ffffffff8121b8d2>] ? kmem_cache_alloc_trace+0x182/0x1d0
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[<ffffffff811b0267>] ? do_init_module+0x27/0x1d8
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[<ffffffff811b029f>] do_init_module+0x5f/0x1d8
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[<ffffffff8112ce35>] load_module+0x1fe5/0x27a0
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[<ffffffff81129870>] ? __symbol_put+0x60/0x60
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[<ffffffff81241690>] ? vfs_read+0x110/0x130
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[<ffffffff8112d866>] SYSC_finit_module+0xe6/0x120
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[<ffffffff8112d8be>] SyS_finit_module+0xe/0x10
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[<ffffffff81003d94>] do_syscall_64+0x64/0x110
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[<ffffffff817c0b61>] entry_SYSCALL64_slow_path+0x25/0x25
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After encountering this, the system-udevd process seems to be blocked
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until it is killed when hitting its timeout of 3min.
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In analogy to the other accesses to members of quirk in usb_audio_probe(),
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check for quirk != NULL before accessing its ->media_device.
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Fixes: aebb2b89bff0 ("[media] sound/usb: Use Media Controller API to share
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media resources")
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Signed-off-by: Nicolai Stange <nicstange@gmail.com>
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---
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sound/usb/card.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/sound/usb/card.c b/sound/usb/card.c
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index 63244bbba8c7..479621e775bc 100644
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--- a/sound/usb/card.c
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+++ b/sound/usb/card.c
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@@ -612,7 +612,7 @@ static int usb_audio_probe(struct usb_interface *intf,
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if (err < 0)
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goto __error;
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- if (quirk->media_device) {
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+ if (quirk && quirk->media_device) {
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/* don't want to fail when media_snd_device_create() fails */
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media_snd_device_create(chip, intf);
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}
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--
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2.5.5
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