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 233E04562B7 for ; Thu, 3 Sep 2026 15:07:27 +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=1788448048; cv=none; b=GE9HmOXvrhK99OPCylsdyRQq4Sdc6Q7mM0Hl1fxSzp49vHRXHQ/TkFYafE27g3R0U28UDD6CUplzgB4eyhZBEWY5pU111QY3osz9OYDNJp4dfUXbUpQBgIw8NTopMO1vlOlpMUJBUHxwAPNZktO2rngea4u6sUwgIm36VANfhEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788448048; c=relaxed/simple; bh=1lEQLRAz9XQa9g6yOY6QDTDgEquBw1j/9KlRYXL0+3A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OMc+V7M3JPYtjdXQ3ezqZaXJEBFUoplwbAhoyp680U2KkQp/ejq+KA7IktX8cMWorVSIF9etbv38yEUQpBgKcQXWKnGUUb7LRUUKIvisGhO9suh6sorZ3p55R3b9jraukcwexvkTH9RFTs7IRwCifjBd3UdWDe49YNB0XWa9MRo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H5nN7yPt; 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="H5nN7yPt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F4B51F00A3A; Thu, 3 Sep 2026 15:07:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788448047; bh=rA+UfU8VSihi/K/nqL5LTR4dMv2fWokDF1ns10gNr6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=H5nN7yPttxqxI1GSgcJ8gTpDlIkO9mIIOWDGegg/vlrWou6SHQnZQYR8cGVWdTquo yc1yvU5z1DQ4COW5rQRRc/y+fxqPMCkppuMSbfpZAlZ4OpgqOINH96unbZpY88FyBO ArzR8tkbaQYyS2CPzRqAPBeel/92sEOpQdA3hU7t78FXZFPZgjNNABocimEzdVvU+t io2y32f0opZ958JWrT6AmCxlGo/GcEOhDCpZTmO+yVoz289aQ+UVG9HGTtbUQwj7AJ aPIysQSRH3I+vxRaNpheSj/24bie0a7+HLZ/yc9lqFs/iWtWX6iLYVKgBhjuyTxc1M xrBza6ZRn+eJg== From: Sasha Levin To: stable@vger.kernel.org Cc: Chengfeng Ye , Jarkko Sakkinen , Sasha Levin Subject: [PATCH 6.6.y] KEYS: trusted: Fix TPM teardown ordering Date: Thu, 3 Sep 2026 11:07:24 -0400 Message-ID: <20260903150724.863748-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090320-bagful-script-16a2@gregkh> References: <2026090320-bagful-script-16a2@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 ddcbfaede6849..3b1ee879419c4 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