[ciqlts8_8] can: bcm: Fix UAF in bcm_proc_show()

[thefossguy-ciq]

• Commit Message Requirements
• Built against Vault/LTS Environment
• kABI Check Passed, where Valid (Pre 9.4 RT does not have kABI stability)
• Boot Test
• Kernel SelfTest results
• Additional Tests as determined relevant

Commit message

jira VULN-36332
cve CVE-2023-52922
commit-author YueHaibing <yuehaibing@huawei.com>
commit 55c3b96074f3f9b0aee19bf93cd71af7516582bb
BUG: KASAN: slab-use-after-free in bcm_proc_show+0x969/0xa80 Read of size 8 at addr ffff888155846230 by task cat/7862
CPU: 1 PID: 7862 Comm: cat Not tainted 6.5.0-rc1-00153-gc8746099c197 #230 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace:
<TASK>
dump_stack_lvl+0xd5/0x150
print_report+0xc1/0x5e0
kasan_report+0xba/0xf0
bcm_proc_show+0x969/0xa80
seq_read_iter+0x4f6/0x1260
seq_read+0x165/0x210
proc_reg_read+0x227/0x300
vfs_read+0x1d5/0x8d0
ksys_read+0x11e/0x240
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Allocated by task 7846:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x9e/0xa0
bcm_sendmsg+0x264b/0x44e0
sock_sendmsg+0xda/0x180
____sys_sendmsg+0x735/0x920
___sys_sendmsg+0x11d/0x1b0
__sys_sendmsg+0xfa/0x1d0
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Freed by task 7846:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x27/0x40
____kasan_slab_free+0x161/0x1c0
slab_free_freelist_hook+0x119/0x220
__kmem_cache_free+0xb4/0x2e0
rcu_core+0x809/0x1bd0
bcm_op is freed before procfs entry be removed in bcm_release(), this lead to bcm_proc_show() may read the freed bcm_op.
Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20230715092543.15548-1-yuehaibing@huawei.com
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
(cherry picked from commit 55c3b96074f3f9b0aee19bf93cd71af7516582bb)
Signed-off-by: Pratham Patel <ppatel@ciq.com>

Kernel build logs

/run/media/kernel/kernel-src-tree
no .config file found, moving on
[TIMER]{MRPROPER}: 0s
x86_64 architecture detected, copying config
'configs/kernel-4.18.0-x86_64.config' -> '.config'
Setting Local Version for build
CONFIG_LOCALVERSION="-_ppatel__ciqlts8_8-581ac8f566a1"
Making olddefconfig
HOSTCC scripts/basic/fixdep
HOSTCC scripts/kconfig/conf.o
YACC scripts/kconfig/zconf.tab.c
LEX scripts/kconfig/zconf.lex.c
HOSTCC scripts/kconfig/zconf.tab.o
HOSTLD scripts/kconfig/conf
scripts/kconfig/conf --olddefconfig Kconfig
#
# configuration written to .config
#
Starting Build
scripts/kconfig/conf --syncconfig Kconfig
SYSTBL arch/x86/include/generated/asm/syscalls_32.h
SYSHDR arch/x86/include/generated/asm/unistd_32_ia32.h
SYSHDR arch/x86/include/generated/asm/unistd_64_x32.h
SYSTBL arch/x86/include/generated/asm/syscalls_64.h
HYPERCALLS arch/x86/include/generated/asm/xen-hypercalls.h
SYSHDR arch/x86/include/generated/uapi/asm/unistd_32.h
SYSHDR arch/x86/include/generated/uapi/asm/unistd_64.h
SYSHDR arch/x86/include/generated/uapi/asm/unistd_x32.h
WRAP arch/x86/include/generated/uapi/asm/bpf_perf_event.h
WRAP arch/x86/include/generated/uapi/asm/poll.h
WRAP arch/x86/include/generated/uapi/asm/socket.h
UPD include/config/kernel.release
UPD include/generated/uapi/linux/version.h
DESCEND objtool
DESCEND bpf/resolve_btfids
[---snip---]
INSTALL sound/usb/snd-usb-audio.ko
INSTALL sound/usb/snd-usbmidi-lib.ko
INSTALL sound/usb/usx2y/snd-usb-us122l.ko
INSTALL sound/usb/usx2y/snd-usb-usx2y.ko
INSTALL sound/virtio/virtio_snd.ko
INSTALL sound/x86/snd-hdmi-lpe-audio.ko
INSTALL sound/xen/snd_xen_front.ko
INSTALL virt/lib/irqbypass.ko
DEPMOD 4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+
[TIMER]{MODULES}: 42s
Making Install
sh ./arch/x86/boot/install.sh 4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+ arch/x86/boot/bzImage \
System.map "/boot"
[TIMER]{INSTALL}: 10s
Checking kABI
kABI check passed
Setting Default Kernel to /boot/vmlinuz-4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+ and Index to 0
The default is /boot/loader/entries/3d9e347e81244bb1a7c9ccdb05863a3e-4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+.conf with index 0 and kernel /boot/vmlinuz-4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+
The default is /boot/loader/entries/3d9e347e81244bb1a7c9ccdb05863a3e-4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+.conf with index 0 and kernel /boot/vmlinuz-4.18.0-_ppatel__ciqlts8_8-581ac8f566a1+
Generating grub configuration file ...
Adding boot menu entry for EFI firmware configuration
done
Hopefully Grub2.0 took everything ... rebooting after time metrices
[TIMER]{MRPROPER}: 0s
[TIMER]{BUILD}: 1285s
[TIMER]{MODULES}: 42s
[TIMER]{INSTALL}: 10s
[TIMER]{TOTAL} 1342s
Rebooting in 10 seconds

kernel-build.log

Kselftests

$ grep '^ok ' kselftest-before.log | wc -l && grep '^ok ' kselftest-after.log | wc -l
02:08:10|
--------+
230
230
$ grep '^not ok ' kselftest-before.log | wc -l && grep '^not ok ' kselftest-after.log | wc -l
62
62

kselftest-after.log
kselftest-before.log

[thefossguy-ciq]

So something terrible happened. GitHub picked the wrong commit to create a PR for. That PR is #176. That fix was already merged a few weeks ago. I rebased and force pushed my branch. This PR contains the same log files as #176 because the log files are for the correct commit. git-send-email would've prevented this but creating GitHub PRs with it is not possible at the moment.

[bmastbergen]

So something terrible happened. GitHub picked the wrong commit to create a PR for. That PR is #176. That fix was already merged a few weeks ago. I rebased and force pushed my branch. This PR contains the same log files as #176 because the log files are for the correct commit. git-send-email would've prevented this but creating GitHub PRs with it is not possible at the moment.

Is this because you used {ppatel}_ciqlts8_8 as the branch name while working on both vulns? I usually name my branches something like {bmastbergen}_ciqlts8_8/VULN-1234 to help keep myself organized, but this may be another reason to uniquely name your branches

[bmastbergen]

🥌

[PlaidCat]

This is mostly because GITHUB doesn't support fastforwarding

[PlaidCat]