Re: [PATCH 0/2] apparmor unaligned memory fixes

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hi Helge,

On Tue, 2025-11-18 at 12:09 +0100, Helge Deller wrote:
> My patch fixed two call sites, but I suspect you see another call site which
> hasn't been fixed yet.
> 
> Can you try attached patch? It might indicate the caller of the function and
> maybe prints the struct name/address which isn't aligned.
> 
> Helge
> 
> 
> diff --git a/security/apparmor/match.c b/security/apparmor/match.c
> index c5a91600842a..b477430c07eb 100644
> --- a/security/apparmor/match.c
> +++ b/security/apparmor/match.c
> @@ -313,6 +313,9 @@ struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
>  	if (size < sizeof(struct table_set_header))
>  		goto fail;
>  
> +	if (WARN_ON(((unsigned long)data) & (BITS_PER_LONG/8 - 1)))
> +		pr_warn("dfa blob stream %pS not aligned.\n", data);
> +
>  	if (ntohl(*(__be32 *) data) != YYTH_MAGIC)
>  		goto fail;

Here is the relevant output with the patch applied:

[   73.840639] ------------[ cut here ]------------
[   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
[   75.775337] Kernel unaligned access at TPC[8dac18] aa_dfa_unpack+0x58/0x720
[   75.866840] Kernel unaligned access at TPC[8dad00] aa_dfa_unpack+0x140/0x720
[   75.959481] Kernel unaligned access at TPC[8dad00] aa_dfa_unpack+0x140/0x720
[   76.052125] Kernel unaligned access at TPC[8dad00] aa_dfa_unpack+0x140/0x720
[   76.146188] ------------[ cut here ]------------
[   76.206858] WARNING: CPU: 0 PID: 341 at security/apparmor/match.c:316 aa_dfa_unpack+0x6cc/0x720
[   76.321326] 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
[   76.734360] CPU: 0 UID: 0 PID: 341 Comm: apparmor_parser Tainted: G        W           6.18.0-rc6+ #9 NONE 
[   76.862518] Tainted: [W]=WARN
[   76.901396] Call Trace:
[   76.933421] [<0000000000434c24>] dump_stack+0x8/0x18
[   76.998616] [<0000000000476438>] __warn+0xd8/0x100
[   77.061522] [<00000000004296d4>] warn_slowpath_fmt+0x34/0x74
[   77.135867] [<00000000008db28c>] aa_dfa_unpack+0x6cc/0x720
[   77.207923] [<00000000008e643c>] unpack_pdb+0xbc/0x7e0
[   77.275405] [<00000000008e71dc>] unpack_profile+0x67c/0x1300
[   77.349749] [<00000000008e82e0>] aa_unpack+0xe0/0x6a0
[   77.416084] [<00000000008e3ec4>] aa_replace_profiles+0x64/0x1160
[   77.495003] [<00000000008d4d90>] policy_update+0xf0/0x280
[   77.565915] [<00000000008d4fc8>] profile_replace+0xa8/0x100
[   77.639116] [<0000000000766bd0>] vfs_write+0x90/0x420
[   77.705454] [<00000000007670cc>] ksys_write+0x4c/0xe0
[   77.771792] [<0000000000767174>] sys_write+0x14/0x40
[   77.836986] [<0000000000406174>] linux_sparc_syscall+0x34/0x44
[   77.913633] ---[ end trace 0000000000000000 ]---

The message is repeated multiple times.

Adrian


-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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