CVE-2026-46254: AppArmor: Allow apparmor to handle unaligned dfa tables

CVE-2026-46254: AppArmor: Allow apparmor to handle unaligned dfa tables

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

AppArmor: Allow apparmor to handle unaligned dfa tables

The dfa tables can originate from kernel or userspace and 8-byte alignment
isn't always guaranteed and as such may trigger unaligned memory accesses
on various architectures. Resulting in the following

[   73.901376] WARNING: CPU: 0 PID: 341 at security/apparmor/match.c:316 aa_dfa_unpack+0x6cc/0x720
[   74.015867] Modules linked in: binfmt_misc evdev flash sg drm drm_panel_orientation_quirks backlight i2c_core configfs nfnetlink autofs4 ext4 crc16 mbcache jbd2 hid_generic usbhid sr_mod hid cdrom
sd_mod ata_generic ohci_pci ehci_pci ehci_hcd ohci_hcd pata_ali libata sym53c8xx scsi_transport_spi tg3 scsi_mod usbcore libphy scsi_common mdio_bus usb_common
[   74.428977] CPU: 0 UID: 0 PID: 341 Comm: apparmor_parser Not tainted 6.18.0-rc6+ #9 NONE
[   74.536543] Call Trace:
[   74.568561] [<0000000000434c24>] dump_stack+0x8/0x18
[   74.633757] [<0000000000476438>] __warn+0xd8/0x100
[   74.696664] [<00000000004296d4>] warn_slowpath_fmt+0x34/0x74
[   74.771006] [<00000000008db28c>] aa_dfa_unpack+0x6cc/0x720
[   74.843062] [<00000000008e643c>] unpack_pdb+0xbc/0x7e0
[   74.910545] [<00000000008e7740>] unpack_profile+0xbe0/0x1300
[   74.984888] [<00000000008e82e0>] aa_unpack+0xe0/0x6a0
[   75.051226] [<00000000008e3ec4>] aa_replace_profiles+0x64/0x1160
[   75.130144] [<00000000008d4d90>] policy_update+0xf0/0x280
[   75.201057] [<00000000008d4fc8>] profile_replace+0xa8/0x100
[   75.274258] [<0000000000766bd0>] vfs_write+0x90/0x420
[   75.340594] [<00000000007670cc>] ksys_write+0x4c/0xe0
[   75.406932] [<0000000000767174>] sys_write+0x14/0x40
[   75.472126] [<0000000000406174>] linux_sparc_syscall+0x34/0x44
[   75.548802] ---[ end trace 0000000000000000 ]---
[   75.609503] dfa blob stream 0xfff0000008926b96 not aligned.
[   75.682695] Kernel unaligned access at TPC[8db2a8] aa_dfa_unpack+0x6e8/0x720

Work around it by using the get_unaligned_xx() helpers.

The Linux kernel CVE team has assigned CVE-2026-46254 to this issue.


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

	Issue introduced in 4.11 with commit e6e8bf418850d7958311a96ccfb594f2bcc8313e and fixed in 6.12.75 with commit ec737e7fdf2f0ba7b203d4ec72cc915978b10e7e
	Issue introduced in 4.11 with commit e6e8bf418850d7958311a96ccfb594f2bcc8313e and fixed in 6.18.14 with commit 23f112bd6144e815153462e12d313ac3e7027168
	Issue introduced in 4.11 with commit e6e8bf418850d7958311a96ccfb594f2bcc8313e and fixed in 6.19.4 with commit cded636008bde2b397a7cf63b8299d7c303aaf6a
	Issue introduced in 4.11 with commit e6e8bf418850d7958311a96ccfb594f2bcc8313e and fixed in 7.0 with commit 64802f731214a51dfe3c6c27636b3ddafd003eb0

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-2026-46254
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/match.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/ec737e7fdf2f0ba7b203d4ec72cc915978b10e7e
	https://git.kernel.org/stable/c/23f112bd6144e815153462e12d313ac3e7027168
	https://git.kernel.org/stable/c/cded636008bde2b397a7cf63b8299d7c303aaf6a
	https://git.kernel.org/stable/c/64802f731214a51dfe3c6c27636b3ddafd003eb0