linux/security
Mimi Zohar 92063f3ca7 integrity: double check iint_cache was initialized
The kernel may be built with multiple LSMs, but only a subset may be
enabled on the boot command line by specifying "lsm=".  Not including
"integrity" on the ordered LSM list may result in a NULL deref.

As reported by Dmitry Vyukov:
in qemu:
qemu-system-x86_64       -enable-kvm     -machine q35,nvdimm -cpu
max,migratable=off -smp 4       -m 4G,slots=4,maxmem=16G        -hda
wheezy.img      -kernel arch/x86/boot/bzImage   -nographic -vga std
 -soundhw all     -usb -usbdevice tablet  -bt hci -bt device:keyboard
   -net user,host=10.0.2.10,hostfwd=tcp::10022-:22 -net
nic,model=virtio-net-pci   -object
memory-backend-file,id=pmem1,share=off,mem-path=/dev/zero,size=64M
  -device nvdimm,id=nvdimm1,memdev=pmem1  -append "console=ttyS0
root=/dev/sda earlyprintk=serial rodata=n oops=panic panic_on_warn=1
panic=86400 lsm=smack numa=fake=2 nopcid dummy_hcd.num=8"   -pidfile
vm_pid -m 2G -cpu host

But it crashes on NULL deref in integrity_inode_get during boot:

Run /sbin/init as init process
BUG: kernel NULL pointer dereference, address: 000000000000001c
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc2+ #97
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
rel-1.13.0-44-g88ab0c15525c-prebuilt.qemu.org 04/01/2014
RIP: 0010:kmem_cache_alloc+0x2b/0x370 mm/slub.c:2920
Code: 57 41 56 41 55 41 54 41 89 f4 55 48 89 fd 53 48 83 ec 10 44 8b
3d d9 1f 90 0b 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 31 c0 <8b> 5f
1c 4cf
RSP: 0000:ffffc9000032f9d8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888017fc4f00 RCX: 0000000000000000
RDX: ffff888040220000 RSI: 0000000000000c40 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffff888019263627
R10: ffffffff83937cd1 R11: 0000000000000000 R12: 0000000000000c40
R13: ffff888019263538 R14: 0000000000000000 R15: 0000000000ffffff
FS:  0000000000000000(0000) GS:ffff88802d180000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000001c CR3: 000000000b48e000 CR4: 0000000000750ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 integrity_inode_get+0x47/0x260 security/integrity/iint.c:105
 process_measurement+0x33d/0x17e0 security/integrity/ima/ima_main.c:237
 ima_bprm_check+0xde/0x210 security/integrity/ima/ima_main.c:474
 security_bprm_check+0x7d/0xa0 security/security.c:845
 search_binary_handler fs/exec.c:1708 [inline]
 exec_binprm fs/exec.c:1761 [inline]
 bprm_execve fs/exec.c:1830 [inline]
 bprm_execve+0x764/0x19a0 fs/exec.c:1792
 kernel_execve+0x370/0x460 fs/exec.c:1973
 try_to_run_init_process+0x14/0x4e init/main.c:1366
 kernel_init+0x11d/0x1b8 init/main.c:1477
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
CR2: 000000000000001c
---[ end trace 22d601a500de7d79 ]---

Since LSMs and IMA may be configured at build time, but not enabled at
run time, panic the system if "integrity" was not initialized before use.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: 79f7865d84 ("LSM: Introduce "lsm=" for boottime LSM selection")
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-03-22 14:54:11 -04:00
..
apparmor apparmor: handle idmapped mounts 2021-01-24 14:27:20 +01:00
bpf bpf: Implement task local storage 2020-11-06 08:08:37 -08:00
integrity integrity: double check iint_cache was initialized 2021-03-22 14:54:11 -04:00
keys Keyrings miscellany 2021-02-23 16:09:23 -08:00
loadpin LSM: Add "contents" flag to kernel_read_file hook 2020-10-05 13:37:03 +02:00
lockdown Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2020-06-02 17:36:24 -07:00
safesetid LSM: SafeSetID: Fix warnings reported by test bot 2020-10-13 09:17:36 -07:00
selinux idmapped-mounts-v5.12 2021-02-23 13:39:45 -08:00
smack idmapped-mounts-v5.12 2021-02-23 13:39:45 -08:00
tomoyo tomoyo: recognize kernel threads correctly 2021-02-01 11:53:05 +09:00
yama task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
commoncap.c Revert 95ebabde38 ("capabilities: Don't allow writing ambiguous v3 file capabilities") 2021-03-12 15:27:14 -06:00
device_cgroup.c device_cgroup: Fix RCU list debugging warning 2020-08-20 11:25:03 -07:00
inode.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
Kconfig Replace HTTP links with HTTPS ones: security 2020-08-06 12:00:05 -07:00
Kconfig.hardening security: allow using Clang's zero initialization for stack variables 2020-06-16 02:06:23 -07:00
lsm_audit.c make dump_common_audit_data() safe to be called from RCU pathwalk 2021-01-16 15:12:08 -05:00
Makefile device_cgroup: Cleanup cgroup eBPF device filter code 2020-04-13 14:41:54 -04:00
min_addr.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
security.c idmapped-mounts-v5.12 2021-02-23 13:39:45 -08:00