On 23/09/22 11:49AM, Takashi Iwai wrote: > On Fri, 22 Sep 2023 10:46:26 +0200, > Takashi Iwai wrote: > > > > On Fri, 22 Sep 2023 02:51:53 +0200, > > Ricardo B. Marliere wrote: > > > > > > Syzbot reports a slab-out-of-bounds read of a snd_card object. When > > > snd_usb_audio_create calls snd_card_new, it passes sizeof(*chip) as the > > > extra_size argument, which is not enough in this case. > > > > > > Relevant logs below: > > > > > > BUG: KASAN: slab-out-of-bounds in imon_probe+0x2983/0x3910 > > > Read of size 1 at addr ffff8880436a2c71 by task kworker/1:2/777 > > > (...) > > > The buggy address belongs to the object at ffff8880436a2000 > > > which belongs to the cache kmalloc-4k of size 4096 > > > The buggy address is located 1 bytes to the right of > > > allocated 3184-byte region [ffff8880436a2000, ffff8880436a2c70) > > > > > > Reported-by: syzbot+59875ffef5cb9c9b29e9@xxxxxxxxxxxxxxxxxxxxxxxxx > > > Closes: https://lore.kernel.org/all/000000000000a838aa0603cc74d6@xxxxxxxxx/m > > > Signed-off-by: Ricardo B. Marliere <ricardo@xxxxxxxxxxxx> > > > --- > > > sound/usb/card.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/sound/usb/card.c b/sound/usb/card.c > > > index 1b2edc0fd2e9..6578326d33e8 100644 > > > --- a/sound/usb/card.c > > > +++ b/sound/usb/card.c > > > @@ -619,7 +619,7 @@ static int snd_usb_audio_create(struct usb_interface *intf, > > > } > > > > > > err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE, > > > - sizeof(*chip), &card); > > > + sizeof(*chip) + 2, &card); > > > > Sorry, it's no-no. We have to fix the cause of the OOB access instead > > of papering over with a random number of increase. > > > > Unfortunately, most important piece of information is trimmed in the > > changelog, so I can't judge what's going on. The only useful info > > there is that it's something to do with imon driver, but it's > > completely independent from USB-audio. How does it access to the > > external memory allocated by snd-usb-audio driver at all? > > > > Before jumping to the solution, we must understand the problem. > > Now I took a look at the syzbot URL and got more info. > > Through a quick glance, my wild guess is that two different drivers > are bound to two interfaces of the device, the first one to usb-audio > and the second one to imon. And imon driver blindly assumes that the > first interface is bound with imon, too, and that can be the cause. > A patch like below (totally untested!) might fix the problem. > > Can you reproduce the problem in your side? Or did you pick this up > randomly without testing? Thanks for the valuable info! I tested your proposed patch and it works. Will you send it as a proper patch or can the maintainers pick it from here? > > In anyway, let's put media people to Cc. > > > thanks, > > Takashi > > --- a/drivers/media/rc/imon.c > +++ b/drivers/media/rc/imon.c > @@ -2427,6 +2427,12 @@ static int imon_probe(struct usb_interface *interface, > goto fail; > } > > + if (first_if->dev.driver != interface->dev.driver) { > + dev_err(&interface->dev, "inconsistent driver matching\n"); > + ret = -EINVAL; > + goto fail; > + } > + > if (ifnum == 0) { > ictx = imon_init_intf0(interface, id); > if (!ictx) { Tested-by: Ricardo B. Marliere <ricardo@xxxxxxxxxxxx> Linux garage 6.6.0-rc2-next-20230921-dirty #15 SMP PREEMPT_DYNAMIC Fri Sep 22 07:29:07 -03 2023 x86_64 The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. Last login: Tue Sep 19 21:04:06 UTC 2023 on ttyS0 10:31:03 root@garage ~ # ./syz-execprog repsyz 2023/09/22 10:31:08 parsed 1 programs [ 43.416521][ T8175] cc1plus (8175) used greatest stack depth: 22080 bytes left [ 43.470240][ T8179] cc1plus (8179) used greatest stack depth: 22008 bytes left [ 49.171720][ T8224] Adding 124996k swap on ./swap-file. Priority:0 extents:23 across:1427660k [ 49.178542][ T8224] syz-executor (8224) used greatest stack depth: 21096 bytes left 2023/09/22 10:31:15 executed programs: 0 [ 49.233026][ T55] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1 [ 49.234270][ T55] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9 [ 49.235218][ T55] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9 [ 49.236338][ T55] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4 [ 49.237283][ T55] Bluetooth: hci0: unexpected cc 0x0c25 length: 249 > 3 [ 49.238146][ T55] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2 [ 49.355885][ T8240] chnl_net:caif_netlink_parms(): no params data found [ 49.395950][ T8240] bridge0: port 1(bridge_slave_0) entered blocking state [ 49.396944][ T8240] bridge0: port 1(bridge_slave_0) entered disabled state [ 49.397714][ T8240] bridge_slave_0: entered allmulticast mode [ 49.398831][ T8240] bridge_slave_0: entered promiscuous mode [ 49.401610][ T8240] bridge0: port 2(bridge_slave_1) entered blocking state [ 49.402380][ T8240] bridge0: port 2(bridge_slave_1) entered disabled state [ 49.403189][ T8240] bridge_slave_1: entered allmulticast mode [ 49.404311][ T8240] bridge_slave_1: entered promiscuous mode [ 49.421315][ T8240] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link [ 49.423376][ T8240] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link [ 49.440902][ T8240] team0: Port device team_slave_0 added [ 49.442592][ T8240] team0: Port device team_slave_1 added [ 49.457205][ T8240] batman_adv: batadv0: Adding interface: batadv_slave_0 [ 49.458088][ T8240] batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. [ 49.461793][ T8240] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active [ 49.464566][ T8240] batman_adv: batadv0: Adding interface: batadv_slave_1 [ 49.465329][ T8240] batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. [ 49.468023][ T8240] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active [ 49.491775][ T8240] hsr_slave_0: entered promiscuous mode [ 49.493000][ T8240] hsr_slave_1: entered promiscuous mode [ 49.576424][ T8240] netdevsim netdevsim1 netdevsim0: renamed from eth0 [ 49.580029][ T8240] netdevsim netdevsim1 netdevsim1: renamed from eth1 [ 49.582870][ T8240] netdevsim netdevsim1 netdevsim2: renamed from eth2 [ 49.585559][ T8240] netdevsim netdevsim1 netdevsim3: renamed from eth3 [ 49.598460][ T8240] bridge0: port 2(bridge_slave_1) entered blocking state [ 49.599405][ T8240] bridge0: port 2(bridge_slave_1) entered forwarding state [ 49.600596][ T8240] bridge0: port 1(bridge_slave_0) entered blocking state [ 49.601368][ T8240] bridge0: port 1(bridge_slave_0) entered forwarding state [ 49.632834][ T8240] 8021q: adding VLAN 0 to HW filter on device bond0 [ 49.638691][ T23] bridge0: port 1(bridge_slave_0) entered disabled state [ 49.651679][ T23] bridge0: port 2(bridge_slave_1) entered disabled state [ 49.656749][ T8240] 8021q: adding VLAN 0 to HW filter on device team0 [ 49.661350][ T31] bridge0: port 1(bridge_slave_0) entered blocking state [ 49.662190][ T31] bridge0: port 1(bridge_slave_0) entered forwarding state [ 49.673212][ T765] bridge0: port 2(bridge_slave_1) entered blocking state [ 49.674679][ T765] bridge0: port 2(bridge_slave_1) entered forwarding state [ 49.698632][ T8240] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network [ 49.702458][ T8240] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network [ 49.778155][ T8240] 8021q: adding VLAN 0 to HW filter on device batadv0 [ 49.802649][ T8240] veth0_vlan: entered promiscuous mode [ 49.806107][ T8240] veth1_vlan: entered promiscuous mode [ 49.818270][ T8240] veth0_macvtap: entered promiscuous mode [ 49.822124][ T8240] veth1_macvtap: entered promiscuous mode [ 49.829757][ T8240] batman_adv: batadv0: Interface activated: batadv_slave_0 [ 49.833955][ T8240] batman_adv: batadv0: Interface activated: batadv_slave_1 [ 49.836876][ T8240] netdevsim netdevsim1 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0 [ 49.837861][ T8240] netdevsim netdevsim1 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0 [ 49.838840][ T8240] netdevsim netdevsim1 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0 [ 49.840126][ T8240] netdevsim netdevsim1 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 [ 49.893587][ T8569] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 [ 49.894469][ T8569] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 [ 49.917314][ T8569] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 [ 49.918127][ T8569] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 [ 49.961690][ T8587] UDC core: USB Raw Gadget: couldn't find an available UDC or it's busy [ 49.965046][ T8587] misc raw-gadget: fail, usb_gadget_register_driver returned -16 [ 50.219962][ T765] usb 2-1: new high-speed USB device number 2 using dummy_hcd [ 50.459682][ T765] usb 2-1: Using ep0 maxpacket: 16 [ 50.579830][ T765] usb 2-1: config 1 has too many interfaces: 163, using maximum allowed: 32 [ 50.581753][ T765] usb 2-1: config 1 has an invalid descriptor of length 7, skipping remainder of the config [ 50.583812][ T765] usb 2-1: config 1 has 3 interfaces, different from the descriptor's value: 163 [ 50.585682][ T765] usb 2-1: config 1 interface 1 altsetting 1 endpoint 0x1 has an invalid bInterval 0, changing to 7 [ 50.587870][ T765] usb 2-1: config 1 interface 1 altsetting 1 endpoint 0x1 has invalid wMaxPacketSize 0 [ 50.590104][ T765] usb 2-1: too many endpoints for config 1 interface 2 altsetting 0: 128, using maximum allowed: 30 [ 50.592292][ T765] usb 2-1: config 1 interface 2 altsetting 0 has 0 endpoint descriptors, different from the interface descriptor's value: 128 [ 50.594921][ T765] usb 2-1: config 1 interface 2 altsetting 1 endpoint 0x82 has an invalid bInterval 62, changing to 7 [ 50.597128][ T765] usb 2-1: config 1 interface 2 altsetting 1 endpoint 0x82 has invalid maxpacket 41992, setting to 1024 [ 50.749794][ T765] usb 2-1: New USB device found, idVendor=15c2, idProduct=0039, bcdDevice=80.f3 [ 50.751765][ T765] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 50.753415][ T765] usb 2-1: Product: syz [ 50.754255][ T765] usb 2-1: Manufacturer: syz [ 50.755247][ T765] usb 2-1: SerialNumber: syz [ 50.805761][ T765] imon:imon_find_endpoints: no valid input (IR) endpoint found [ 50.807506][ T765] imon 2-1:1.0: unable to initialize intf0, err -19 [ 50.808934][ T765] imon:imon_probe: failed to initialize context! [ 50.810288][ T765] imon 2-1:1.0: unable to register, err -19 [ 51.069921][ T765] usb 2-1: 2:1 : UAC_AS_GENERAL descriptor not found [ 51.113716][ T765] imon 2-1:1.1: inconsistent driver matching [ 51.121438][ T765] imon 2-1:1.1: unable to register, err -22 [ 51.122866][ T765] imon: probe of 2-1:1.1 failed with error -22 [ 51.132274][ T765] usb 2-1: USB disconnect, device number 2 [ 51.270491][ T4485] Bluetooth: hci0: command 0x0409 tx timeout 10:31:17 root@garage ~ #
