linux/drivers/net
Lyude Paul b72c51a58e brcmfmac: Fix out of bounds memory access during fw load
I ended up tracking down some rather nasty issues with f2fs (and other
filesystem modules) constantly crashing on my kernel down to a
combination of out of bounds memory accesses, one of which was coming
from brcmfmac during module load:

[   30.891382] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4356-sdio for chip BCM4356/2
[   30.894437] ==================================================================
[   30.901581] BUG: KASAN: global-out-of-bounds in brcmf_fw_alloc_request+0x42c/0x480 [brcmfmac]
[   30.909935] Read of size 1 at addr ffff2000024865df by task kworker/6:2/387
[   30.916805]
[   30.918261] CPU: 6 PID: 387 Comm: kworker/6:2 Tainted: G           O      4.20.0-rc3Lyude-Test+ #19
[   30.927251] Hardware name: amlogic khadas-vim2/khadas-vim2, BIOS 2018.07-rc2-armbian 09/11/2018
[   30.935964] Workqueue: events brcmf_driver_register [brcmfmac]
[   30.941641] Call trace:
[   30.944058]  dump_backtrace+0x0/0x3e8
[   30.947676]  show_stack+0x14/0x20
[   30.950968]  dump_stack+0x130/0x1c4
[   30.954406]  print_address_description+0x60/0x25c
[   30.959066]  kasan_report+0x1b4/0x368
[   30.962683]  __asan_report_load1_noabort+0x18/0x20
[   30.967547]  brcmf_fw_alloc_request+0x42c/0x480 [brcmfmac]
[   30.967639]  brcmf_sdio_probe+0x163c/0x2050 [brcmfmac]
[   30.978035]  brcmf_ops_sdio_probe+0x598/0xa08 [brcmfmac]
[   30.983254]  sdio_bus_probe+0x190/0x398
[   30.983270]  really_probe+0x2a0/0xa70
[   30.983296]  driver_probe_device+0x1b4/0x2d8
[   30.994901]  __driver_attach+0x200/0x280
[   30.994914]  bus_for_each_dev+0x10c/0x1a8
[   30.994925]  driver_attach+0x38/0x50
[   30.994935]  bus_add_driver+0x330/0x608
[   30.994953]  driver_register+0x140/0x388
[   31.013965]  sdio_register_driver+0x74/0xa0
[   31.014076]  brcmf_sdio_register+0x14/0x60 [brcmfmac]
[   31.023177]  brcmf_driver_register+0xc/0x18 [brcmfmac]
[   31.023209]  process_one_work+0x654/0x1080
[   31.032266]  worker_thread+0x4f0/0x1308
[   31.032286]  kthread+0x2a8/0x320
[   31.039254]  ret_from_fork+0x10/0x1c
[   31.039269]
[   31.044226] The buggy address belongs to the variable:
[   31.044351]  brcmf_firmware_path+0x11f/0xfffffffffffd3b40 [brcmfmac]
[   31.055601]
[   31.057031] Memory state around the buggy address:
[   31.061800]  ffff200002486480: 04 fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
[   31.068983]  ffff200002486500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   31.068993] >ffff200002486580: 00 00 00 00 00 00 00 00 fa fa fa fa 00 00 00 00
[   31.068999]                                                     ^
[   31.069017]  ffff200002486600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   31.096521]  ffff200002486680: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
[   31.096528] ==================================================================
[   31.096533] Disabling lock debugging due to kernel taint

It appears that when trying to determine the length of the string in the
alternate firmware path, we make the mistake of not handling the case
where the firmware path is empty correctly. Since strlen(mp_path) can
return 0, we'll end up accessing mp_path[-1] when the firmware_path
isn't provided through the module arguments.

So, fix this by just setting the end char to '\0' by default, and only
changing it if we have a non-zero length. Additionally, use strnlen()
with BRCMF_FW_ALTPATH_LEN instead of strlen() just to be extra safe.

Fixes: 2baa3aaee2 ("brcmfmac: introduce brcmf_fw_alloc_request() function")
Cc: Hante Meuleman <hante.meuleman@broadcom.com>
Cc: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Cc: Franky Lin <franky.lin@broadcom.com>
Cc: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Arend Van Spriel <arend.vanspriel@broadcom.com>
Cc: Himanshu Jha <himanshujha199640@gmail.com>
Cc: Dan Haab <dhaab@luxul.com>
Cc: Jia-Shyr Chuang <saint.chuang@cypress.com>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
2018-11-29 17:33:10 +02:00
..
appletalk
arcnet mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
bonding bonding: fix length of actor system 2018-10-29 20:39:38 -07:00
caif
can
dsa net: dsa: qca8k: simplify getting .driver_data 2018-10-21 21:10:11 -07:00
ethernet net: stmmac: Fix stmmac_mdio_reset() when building stmmac as modules 2018-10-31 18:35:58 -07:00
fddi FDDI: defza: Support capturing outgoing SMT traffic 2018-10-15 21:46:06 -07:00
fjes
hamradio Merge branch 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-10-24 14:43:41 +01:00
hippi
hyperv hv_netvsc: fix vf serial matching with pci slot info 2018-10-15 22:58:11 -07:00
ieee802154 Merge branch 'ieee802154-for-davem-2018-10-04' of git://git.kernel.org/pub/scm/linux/kernel/git/sschmidt/wpan-next 2018-10-04 09:32:48 -07:00
ipvlan
netdevsim bpf: add verifier callback to get stack usage info for offloaded progs 2018-10-08 10:24:12 +02:00
phy net: phy: genphy_10g_driver: Avoid NULL pointer dereference 2018-10-25 16:19:09 -07:00
plip
ppp Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-10-25 16:43:35 -07:00
slip change semantics of ldisc ->compat_ioctl() 2018-10-13 00:50:53 -04:00
team netpoll: allow cleanup to be synchronous 2018-10-19 17:01:43 -07:00
usb Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-12 21:38:46 -07:00
vmxnet3
wan Merge branch 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-10-24 14:43:41 +01:00
wimax
wireless brcmfmac: Fix out of bounds memory access during fw load 2018-11-29 17:33:10 +02:00
xen-netback Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-03 21:00:17 -07:00
dummy.c
eql.c
geneve.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-19 11:03:06 -07:00
gtp.c
ifb.c
Kconfig
LICENSE.SRC
loopback.c net: loopback: clear skb->tstamp before netif_rx() 2018-10-20 01:01:28 -07:00
macsec.c macsec: let the administrator set UP state even if lowerdev is down 2018-10-28 19:26:42 -07:00
macvlan.c netpoll: allow cleanup to be synchronous 2018-10-19 17:01:43 -07:00
macvtap.c
Makefile
mdio.c
mii.c
net_failover.c
netconsole.c
nlmon.c
ntb_netdev.c ntb_netdev: Simplify remove with client device drvdata 2018-10-31 21:20:05 -04:00
rionet.c
sb1000.c
Space.c
sungem_phy.c
tap.c
thunderbolt.c
tun.c tun: Consistently configure generic netdev params via rtnetlink 2018-10-15 21:40:31 -07:00
veth.c veth: Add ethtool statistics support for XDP 2018-10-15 21:58:46 -07:00
virtio_net.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-19 11:03:06 -07:00
vrf.c ipv6: add vrf table handling code for ipv6 mcast 2018-10-02 22:29:08 -07:00
vsockmon.c
vxlan.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-19 11:03:06 -07:00
xen-netfront.c