From 64802f731214a51dfe3c6c27636b3ddafd003eb0 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Tue, 25 Nov 2025 16:11:07 +0100 Subject: [PATCH] AppArmor: Allow apparmor to handle unaligned dfa tables MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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. Fixes: e6e8bf418850d ("apparmor: fix restricted endian type warnings for dfa unpack") Reported-by: John Paul Adrian Glaubitz Closes: https://github.com/sparclinux/issues/issues/30 Signed-off-by: Helge Deller Signed-off-by: John Johansen --- security/apparmor/match.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/security/apparmor/match.c b/security/apparmor/match.c index c5a91600842a1..26e82ba879d44 100644 --- a/security/apparmor/match.c +++ b/security/apparmor/match.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "include/lib.h" #include "include/match.h" @@ -42,11 +43,11 @@ static struct table_header *unpack_table(char *blob, size_t bsize) /* loaded td_id's start at 1, subtract 1 now to avoid doing * it every time we use td_id as an index */ - th.td_id = be16_to_cpu(*(__be16 *) (blob)) - 1; + th.td_id = get_unaligned_be16(blob) - 1; if (th.td_id > YYTD_ID_MAX) goto out; - th.td_flags = be16_to_cpu(*(__be16 *) (blob + 2)); - th.td_lolen = be32_to_cpu(*(__be32 *) (blob + 8)); + th.td_flags = get_unaligned_be16(blob + 2); + th.td_lolen = get_unaligned_be32(blob + 8); blob += sizeof(struct table_header); if (!(th.td_flags == YYTD_DATA16 || th.td_flags == YYTD_DATA32 || @@ -313,14 +314,14 @@ struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags) if (size < sizeof(struct table_set_header)) goto fail; - if (ntohl(*(__be32 *) data) != YYTH_MAGIC) + if (get_unaligned_be32(data) != YYTH_MAGIC) goto fail; - hsize = ntohl(*(__be32 *) (data + 4)); + hsize = get_unaligned_be32(data + 4); if (size < hsize) goto fail; - dfa->flags = ntohs(*(__be16 *) (data + 12)); + dfa->flags = get_unaligned_be16(data + 12); if (dfa->flags & ~(YYTH_FLAGS)) goto fail; @@ -329,7 +330,7 @@ struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags) * if (dfa->flags & YYTH_FLAGS_OOB_TRANS) { * if (hsize < 16 + 4) * goto fail; - * dfa->max_oob = ntol(*(__be32 *) (data + 16)); + * dfa->max_oob = get_unaligned_be32(data + 16); * if (dfa->max <= MAX_OOB_SUPPORTED) { * pr_err("AppArmor DFA OOB greater than supported\n"); * goto fail; -- 2.47.3