From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3CB764D8D98 for ; Thu, 3 Sep 2026 15:22:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788448926; cv=none; b=Cr6ryK+0MIsy0gSb/76Qm/eARSr6nZ0U5DROwszNkuEeyqP/Oq1L5mH/zzKVjcPiU5tBJzdl6XrqhidJfyCjm8+hdF//JOEwkk3mSe0lPHkVJW1796OE5042/RAX4yGcDxyZge/TOF/xT87XyjTHnghQ093fTVZ0wGVgHMcSdjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788448926; c=relaxed/simple; bh=wZdbPkFIiHWP+2cINcK5FdjPEwfI5HMfgvvGEnAQMXA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I9+cWSa6Unxwa3vWbtLvfcVU9x6U5Tsm0TGrmoF+OYOFozfJvSGSELu8rYgyk0J5utqpugloco7sdmQ7f/eML1rE81V0RkTUH6cSjk8dnaGLEur/rs5KqlEUeXBWR9uGeGPlAJb+/+D4olcPlniz4amFGD+L2rmFAaNL3cbVrOc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IW8MGIZB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IW8MGIZB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 712131F000E9; Thu, 3 Sep 2026 15:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788448925; bh=6DiGJvw26k1t8BX/BCAZQSn+8MNLGNk+vnlPKTV/wrU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IW8MGIZBD+uKCDQCsrJyOXCcpXv2toMpvxcNK6rnZISXB+ggSyWlf2MPHuU/mCZA1 b3FykYramLjGh1T5MVI5138+ePgOqa6A/Va5j9mjuIjM+5ROcJgb9I5PUv0cYrpSFk HOJF7fueggk4Q8xzCV3NdOzUpBecc0bOAhU1GzPKk/8NTjfypzR3MDb7EUAvi3SXBq 4+fugDSaPkdTyXfp0B/oEZMnkU6QYSudbBzRmmHARtM0P+A53AmVX8JtQwj08Uok1o PvACVsGgmFs+jItCh0/a0wyseQlyli7QAcz1xOrqo4k4S5JlJtxnr2+TYEppIaJaqz fPXTiGs/UNlPg== From: Sasha Levin To: stable@vger.kernel.org Cc: Chengfeng Ye , Jarkko Sakkinen , Sasha Levin Subject: [PATCH 5.15.y] KEYS: trusted: Fix TPM teardown ordering Date: Thu, 3 Sep 2026 11:22:02 -0400 Message-ID: <20260903152202.886654-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090321-fiction-outthink-69f9@gregkh> References: <2026090321-fiction-outthink-69f9@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chengfeng Ye [ Upstream commit 5e2d672280d97d83de43031d93761b12dadd7b8a ] trusted_tpm_exit() drops the TPM chip reference and frees the digest array before unregistering the trusted key type. key_type_lookup() holds key_types_sem for reading until the key operation finishes, while unregister_key_type() takes it for writing. It therefore provides the synchronization point that must precede backend teardown. The current order permits this interleaving: CPU 0 CPU 1 trusted_tpm_exit() key_type_lookup("trusted") put_device(&chip->dev) trusted_tpm_seal() kfree(digests) pcrlock() unregister_key_type() tpm_pcr_extend(..., digests) CPU 1 can consequently dereference the freed digest array. The chip can also be released before callbacks stop using it. KASAN reported: BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200 Read of size 2 at addr ffff88810872d000 by task poc/89 Call Trace: tpm_pcr_extend+0x1f0/0x200 pcrlock+0x42/0x70 [trusted] trusted_tpm_seal+0x1b6/0x570 [trusted] trusted_instantiate+0x293/0x340 [trusted] __key_instantiate_and_link+0xb2/0x2b0 __key_create_or_update+0x61e/0xb50 __do_sys_add_key+0x1b8/0x310 Allocated by task 88: __kmalloc_noprof+0x1a7/0x490 do_one_initcall+0xa1/0x390 do_init_module+0x2df/0x840 Freed by task 90: kfree+0x131/0x3c0 trusted_tpm_exit+0x59/0xa0 [trusted] __do_sys_delete_module+0x346/0x510 Move unregister_key_type() before releasing either resource. This stops new lookups and waits for in-flight key operations to finish before the backend state is destroyed. Fixes: 0b6cf6b97b7e ("tpm: pass an array of tpm_extend_digest structures to tpm_pcr_extend()") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Link: https://lore.kernel.org/r/20260731140925.2973492-1-nicoyip.dev@gmail.com Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen [ preserved the additional trusted_shash_release() cleanup after unregister_key_type() ] Signed-off-by: Sasha Levin --- security/keys/trusted-keys/trusted_tpm1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index 4863ee08b7b11..c482c54be918c 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -1058,10 +1058,10 @@ static int __init trusted_tpm_init(void) static void trusted_tpm_exit(void) { if (chip) { + unregister_key_type(&key_type_trusted); put_device(&chip->dev); kfree(digests); trusted_shash_release(); - unregister_key_type(&key_type_trusted); } } -- 2.53.0