* [BUG] security/keys: out-of-bounds in tpm2_unseal_trusted()
@ 2026-08-27 12:42 co
2026-08-28 5:17 ` Jarkko Sakkinen
0 siblings, 1 reply; 2+ messages in thread
From: co @ 2026-08-27 12:42 UTC (permalink / raw)
To: linux-integrity, keyrings, linux-security-module,
James Bottomley, Jarkko Sakkinen, Mimi Zohar, David Howells,
Paul Moore, James Morris, Serge E. Hallyn, linux-kernel
We found a bug reachable in:
path security/keys/trusted-keys
crash out-of-bounds in tpm2_unseal_trusted()
commit 2709dd5ae32f ("Merge tag 'sched-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
Config, environment, the sanitizer report and a C reproducer follow.
== Notes ===============================================================
If you patch the bug based on our artifacts, a tag would be
appreciated:
Reported-by: co+6a581c4284f721d4@bugs.sh
Everything in this mail is validated by the reproducer below.
We also hold an LLM-generated root-cause analysis and a candidate
patch. The patch passes an A/B test: the same reproducer panics the
unpatched kernel and runs clean on the patched one. Neither has had
human review, so both still require validation before you send or
apply them. Available on:
patch.diff https://bugs.sh/b/6a581c4284f721d4/patch.diff
report.md https://bugs.sh/b/6a581c4284f721d4/report.md
This is an open science project. The code and the full set of PoCs
are not public at this moment, as we intend to disclose our findings
in an ethical way.
Happy to test patches. Complaints and suggestions about our work
are welcome at:
cedalion@bugs.sh
== Environment =========================================================
Reproduced on 2709dd5ae32f ("Merge tag 'sched-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
VM setup https://bugs.sh/b/6a581c4284f721d4/run.sh
config https://bugs.sh/b/6a581c4284f721d4/config.gz
poc https://bugs.sh/b/6a581c4284f721d4/repro.c
== Sanitizer Report ====================================================
BUG: KASAN: slab-out-of-bounds in tpm2_unseal_trusted (./include/linux/unaligned.h:48 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:408 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:595 (discriminator 1))
Read of size 2 at addr ffff8880125db7aa by task exploit/149
CPU: 0 UID: 1000 PID: 149 Comm: exploit Tainted: G W 7.2.0+ #31 PREEMPTLAZY
Call Trace:
dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:595)
tpm2_unseal_trusted (./include/linux/unaligned.h:48 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:408 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:595 (discriminator 1))
trusted_tpm_unseal (security/keys/trusted-keys/trusted_tpm1.c:928)
trusted_instantiate (security/keys/trusted-keys/trusted_core.c:196)
__key_instantiate_and_link (security/keys/key.c:446)
__key_create_or_update (security/keys/key.c:941)
key_create_or_update (security/keys/key.c:1021)
__do_sys_add_key (security/keys/keyctl.c:134)
do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Allocated by task 149:
kasan_save_stack (mm/kasan/common.c:57)
kasan_save_track (mm/kasan/common.c:78)
__kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)
__kmalloc_noprof (./include/linux/kasan.h:263 mm/slub.c:5337 mm/slub.c:5362)
tpm2_unseal_trusted (./include/linux/slab.h:992 security/keys/trusted-keys/trusted_tpm2.c:119 security/keys/trusted-keys/trusted_tpm2.c:384 security/keys/trusted-keys/trusted_tpm2.c:595)
trusted_tpm_unseal (security/keys/trusted-keys/trusted_tpm1.c:928)
trusted_instantiate (security/keys/trusted-keys/trusted_core.c:196)
__key_instantiate_and_link (security/keys/key.c:446)
__key_create_or_update (security/keys/key.c:941)
key_create_or_update (security/keys/key.c:1021)
__do_sys_add_key (security/keys/keyctl.c:134)
do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
The buggy address belongs to the object at ffff8880125db7a0
which belongs to the cache kmalloc-8 of size 8
The buggy address is located 2 bytes to the right of
allocated 8-byte region [ffff8880125db7a0, ffff8880125db7a8)
The buggy address belongs to the physical page:
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880125db680: 00 fc fc fc fa fc fc fc 00 fc fc fc fc fc fc fc
ffff8880125db700: fc fc fc fc fc fc fc fc fa fc fc fc 00 fc fc fc
>ffff8880125db780: fc fc fc fc 00 fc fc fc fa fc fc fc fc fc fc fc
^
ffff8880125db800: fc fc fc fc fa fc fc fc 07 fc fc fc fc fc fc fc
ffff8880125db880: fa fc fc fc fc fc fc fc fc fc fc fc 00 fc fc fc
---
The report format is based on syzbot bug report.
This report is generated by a bot. It may contain errors.
See https://github.com/n132/cedalion for more information.
For any issue with this report, reach out to cedalion@bugs.sh
If the report is already addressed, let us know by replying with:
#co fix: <commit hash>
If the report is a duplicate of another one, reply with:
#co dup: <lore link>
If you want to undo deduplication, reply with:
#co undup
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [BUG] security/keys: out-of-bounds in tpm2_unseal_trusted()
2026-08-27 12:42 [BUG] security/keys: out-of-bounds in tpm2_unseal_trusted() co
@ 2026-08-28 5:17 ` Jarkko Sakkinen
0 siblings, 0 replies; 2+ messages in thread
From: Jarkko Sakkinen @ 2026-08-28 5:17 UTC (permalink / raw)
To: co
Cc: linux-integrity, keyrings, linux-security-module,
James Bottomley, Mimi Zohar, David Howells, Paul Moore,
James Morris, Serge E. Hallyn, linux-kernel
On Thu, Aug 27, 2026 at 12:42:08PM +0000, co wrote:
> We found a bug reachable in:
>
> path security/keys/trusted-keys
> crash out-of-bounds in tpm2_unseal_trusted()
> commit 2709dd5ae32f ("Merge tag 'sched-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
>
> Config, environment, the sanitizer report and a C reproducer follow.
>
> == Notes ===============================================================
> If you patch the bug based on our artifacts, a tag would be
> appreciated:
>
> Reported-by: co+6a581c4284f721d4@bugs.sh
>
> Everything in this mail is validated by the reproducer below.
>
> We also hold an LLM-generated root-cause analysis and a candidate
> patch. The patch passes an A/B test: the same reproducer panics the
> unpatched kernel and runs clean on the patched one. Neither has had
> human review, so both still require validation before you send or
> apply them. Available on:
>
> patch.diff https://bugs.sh/b/6a581c4284f721d4/patch.diff
> report.md https://bugs.sh/b/6a581c4284f721d4/report.md
>
> This is an open science project. The code and the full set of PoCs
> are not public at this moment, as we intend to disclose our findings
> in an ethical way.
>
> Happy to test patches. Complaints and suggestions about our work
> are welcome at:
>
> cedalion@bugs.sh
>
> == Environment =========================================================
> Reproduced on 2709dd5ae32f ("Merge tag 'sched-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
> VM setup https://bugs.sh/b/6a581c4284f721d4/run.sh
> config https://bugs.sh/b/6a581c4284f721d4/config.gz
> poc https://bugs.sh/b/6a581c4284f721d4/repro.c
>
> == Sanitizer Report ====================================================
> BUG: KASAN: slab-out-of-bounds in tpm2_unseal_trusted (./include/linux/unaligned.h:48 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:408 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:595 (discriminator 1))
> Read of size 2 at addr ffff8880125db7aa by task exploit/149
> CPU: 0 UID: 1000 PID: 149 Comm: exploit Tainted: G W 7.2.0+ #31 PREEMPTLAZY
> Call Trace:
> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
> print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)
> kasan_report (mm/kasan/report.c:595)
> tpm2_unseal_trusted (./include/linux/unaligned.h:48 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:408 (discriminator 1) security/keys/trusted-keys/trusted_tpm2.c:595 (discriminator 1))
> trusted_tpm_unseal (security/keys/trusted-keys/trusted_tpm1.c:928)
> trusted_instantiate (security/keys/trusted-keys/trusted_core.c:196)
> __key_instantiate_and_link (security/keys/key.c:446)
> __key_create_or_update (security/keys/key.c:941)
> key_create_or_update (security/keys/key.c:1021)
> __do_sys_add_key (security/keys/keyctl.c:134)
> do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)
> entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
> Allocated by task 149:
> kasan_save_stack (mm/kasan/common.c:57)
> kasan_save_track (mm/kasan/common.c:78)
> __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)
> __kmalloc_noprof (./include/linux/kasan.h:263 mm/slub.c:5337 mm/slub.c:5362)
> tpm2_unseal_trusted (./include/linux/slab.h:992 security/keys/trusted-keys/trusted_tpm2.c:119 security/keys/trusted-keys/trusted_tpm2.c:384 security/keys/trusted-keys/trusted_tpm2.c:595)
> trusted_tpm_unseal (security/keys/trusted-keys/trusted_tpm1.c:928)
> trusted_instantiate (security/keys/trusted-keys/trusted_core.c:196)
> __key_instantiate_and_link (security/keys/key.c:446)
> __key_create_or_update (security/keys/key.c:941)
> key_create_or_update (security/keys/key.c:1021)
> __do_sys_add_key (security/keys/keyctl.c:134)
> do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)
> entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
> The buggy address belongs to the object at ffff8880125db7a0
> which belongs to the cache kmalloc-8 of size 8
> The buggy address is located 2 bytes to the right of
> allocated 8-byte region [ffff8880125db7a0, ffff8880125db7a8)
> The buggy address belongs to the physical page:
> page dumped because: kasan: bad access detected
> Memory state around the buggy address:
> ffff8880125db680: 00 fc fc fc fa fc fc fc 00 fc fc fc fc fc fc fc
> ffff8880125db700: fc fc fc fc fc fc fc fc fa fc fc fc 00 fc fc fc
> >ffff8880125db780: fc fc fc fc 00 fc fc fc fa fc fc fc fc fc fc fc
> ^
> ffff8880125db800: fc fc fc fc fa fc fc fc 07 fc fc fc fc fc fc fc
> ffff8880125db880: fa fc fc fc fc fc fc fc fc fc fc fc 00 fc fc fc
>
>
> ---
> The report format is based on syzbot bug report.
>
> This report is generated by a bot. It may contain errors.
> See https://github.com/n132/cedalion for more information.
>
> For any issue with this report, reach out to cedalion@bugs.sh
>
> If the report is already addressed, let us know by replying with:
> #co fix: <commit hash>
>
> If the report is a duplicate of another one, reply with:
> #co dup: <lore link>
>
> If you want to undo deduplication, reply with:
> #co undup
>
>
ack as for acknowledging this. i'll look this on monday in detail
(my work week is over and i have weekend activities).
Thank you for reporting!
BR, Jarkko
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2026-08-27 12:42 [BUG] security/keys: out-of-bounds in tpm2_unseal_trusted() co
2026-08-28 5:17 ` Jarkko Sakkinen
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