Subject: CVE-2024-46721: apparmor: fix possible NULL pointer dereference

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

apparmor: fix possible NULL pointer dereference

profile->parent->dents[AAFS_PROF_DIR] could be NULL only if its parent is made
from __create_missing_ancestors(..) and 'ent->old' is NULL in
aa_replace_profiles(..).
In that case, it must return an error code and the code, -ENOENT represents
its state that the path of its parent is not existed yet.

BUG: kernel NULL pointer dereference, address: 0000000000000030
PGD 0 P4D 0
PREEMPT SMP PTI
CPU: 4 PID: 3362 Comm: apparmor_parser Not tainted 6.8.0-24-generic #24
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:aafs_create.constprop.0+0x7f/0x130
Code: 4c 63 e0 48 83 c4 18 4c 89 e0 5b 41 5c 41 5d 41 5e 41 5f 5d 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 45 31 d2 c3 cc cc cc cc <4d> 8b 55 30 4d 8d ba a0 00 00 00 4c 89 55 c0 4c 89 ff e8 7a 6a ae
RSP: 0018:ffffc9000b2c7c98 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000041ed RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000b2c7cd8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82baac10
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007be9f22cf740(0000) GS:ffff88817bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000030 CR3: 0000000134b08000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 ? show_regs+0x6d/0x80
 ? __die+0x24/0x80
 ? page_fault_oops+0x99/0x1b0
 ? kernelmode_fixup_or_oops+0xb2/0x140
 ? __bad_area_nosemaphore+0x1a5/0x2c0
 ? find_vma+0x34/0x60
 ? bad_area_nosemaphore+0x16/0x30
 ? do_user_addr_fault+0x2a2/0x6b0
 ? exc_page_fault+0x83/0x1b0
 ? asm_exc_page_fault+0x27/0x30
 ? aafs_create.constprop.0+0x7f/0x130
 ? aafs_create.constprop.0+0x51/0x130
 __aafs_profile_mkdir+0x3d6/0x480
 aa_replace_profiles+0x83f/0x1270
 policy_update+0xe3/0x180
 profile_load+0xbc/0x150
 ? rw_verify_area+0x47/0x140
 vfs_write+0x100/0x480
 ? __x64_sys_openat+0x55/0xa0
 ? syscall_exit_to_user_mode+0x86/0x260
 ksys_write+0x73/0x100
 __x64_sys_write+0x19/0x30
 x64_sys_call+0x7e/0x25c0
 do_syscall_64+0x7f/0x180
 entry_SYSCALL_64_after_hwframe+0x78/0x80
RIP: 0033:0x7be9f211c574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007ffd26f2b8c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00005d504415e200 RCX: 00007be9f211c574
RDX: 0000000000001fc1 RSI: 00005d504418bc80 RDI: 0000000000000004
RBP: 0000000000001fc1 R08: 0000000000001fc1 R09: 0000000080000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005d504418bc80
R13: 0000000000000004 R14: 00007ffd26f2b9b0 R15: 00007ffd26f2ba30
 </TASK>
Modules linked in: snd_seq_dummy snd_hrtimer qrtr snd_hda_codec_generic snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device i2c_i801 snd_timer i2c_smbus qxl snd soundcore drm_ttm_helper lpc_ich ttm joydev input_leds serio_raw mac_hid binfmt_misc msr parport_pc ppdev lp parport efi_pstore nfnetlink dmi_sysfs qemu_fw_cfg ip_tables x_tables autofs4 hid_generic usbhid hid ahci libahci psmouse virtio_rng xhci_pci xhci_pci_renesas
CR2: 0000000000000030
---[ end trace 0000000000000000 ]---
RIP: 0010:aafs_create.constprop.0+0x7f/0x130
Code: 4c 63 e0 48 83 c4 18 4c 89 e0 5b 41 5c 41 5d 41 5e 41 5f 5d 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 45 31 d2 c3 cc cc cc cc <4d> 8b 55 30 4d 8d ba a0 00 00 00 4c 89 55 c0 4c 89 ff e8 7a 6a ae
RSP: 0018:ffffc9000b2c7c98 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000041ed RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000b2c7cd8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82baac10
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007be9f22cf740(0000) GS:ffff88817bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000030 CR3: 0000000134b08000 CR4: 00000000000006f0

The Linux kernel CVE team has assigned CVE-2024-46721 to this issue.

Affected and fixed versions
===========================

	Fixed in 4.19.322 with commit 8d9da10a392a
	Fixed in 5.4.284 with commit 730ee2686af0
	Fixed in 5.10.226 with commit 52338a3aa772
	Fixed in 5.15.167 with commit e3c7d23f7a5c
	Fixed in 6.1.109 with commit 09b2d107fe63
	Fixed in 6.6.50 with commit 59f742e55a46
	Fixed in 6.10.9 with commit c49bbe69ee15
	Fixed in 6.11 with commit 3dd384108d53

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-46721
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	security/apparmor/apparmorfs.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/8d9da10a392a32368392f7a16775e1f36e2a5346
	https://git.kernel.org/stable/c/730ee2686af0d55372e97a2695005ff142702363
	https://git.kernel.org/stable/c/52338a3aa772762b8392ce7cac106c1099aeab85
	https://git.kernel.org/stable/c/e3c7d23f7a5c0b11ba0093cea32261ab8098b94e
	https://git.kernel.org/stable/c/09b2d107fe63e55b6ae643f9f26bf8eb14a261d9
	https://git.kernel.org/stable/c/59f742e55a469ef36c5c1533b6095a103b61eda8
	https://git.kernel.org/stable/c/c49bbe69ee152bd9c1c1f314c0f582e76c578f64
	https://git.kernel.org/stable/c/3dd384108d53834002be5630132ad5c3f32166ad