From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DD6732EA15D for ; Tue, 22 Jul 2025 14:19:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753193961; cv=none; b=XxuLVDFmEPH9d5hE2Om3YGlpylJBzkSEbNN++nUMz3jh4spuHI24HRgJOJAQXduyg6xGncks0nFuI3A+TzXoGLcmL3D2T8+hJt8beuY+U0MT6WUkInH6vOXijMc2RX5VelcmV1yQu/l/nupCESTueWSAa3jloAgXNmsz5GH7zec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753193961; c=relaxed/simple; bh=RI8dZDd9ZT4uQ4WozM+QBiu32S5R56TIBmk2cz2pnNE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=toJiYDwvTPKxSyzIblUaFbdPXZA5TRrSmUEk7eBi7pN43hWvEysRwYSeIhHFCxu04OXZQYHCMT/pRuTNISXhtzvBY9hUNg9yF+mg0SwrXteb5bkjC6gK40PTjwqKhQJgUUD12v36unXSwoNYFBX0Cg7qI0AZTKiFy9oARG/UHZA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qIl6Z6Co; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qIl6Z6Co" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7984BC4CEEB; Tue, 22 Jul 2025 14:19:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753193961; bh=RI8dZDd9ZT4uQ4WozM+QBiu32S5R56TIBmk2cz2pnNE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qIl6Z6Codok5NLf518r11kuFFWN07nC3TBJZhINukS/SAQRi2H0ssj8GylkT66ajT 6Y3ZeQ50zc5zulT+8iqEpjgzXLBscv1KBW8Asr+SLE3N/TSpXqUPjxf8wrUbAhwquh p+QiUV9z90xIlkA8sesgNCGuggsVxNgnbUyveANBWful6S7CVNKNSSvp96m0YhzJ7/ tsJttOdhZO42B1+Xanod+n1pXaFY80Sh5yCncT1Jx6YQh1/PBWyCggROQGSPZKtoQQ JsRD6mPX6yBmj5qurJfsl60ki1F5NMU2yed0Ufqhka/ud70Uuip7bS4gQ8C08atfu5 M3sMvoFxzZ1Uw== From: Sasha Levin To: stable@vger.kernel.org Cc: Wang Zhaolong , Paulo Alcantara , Steve French , Sasha Levin Subject: [PATCH 5.10.y] smb: client: fix use-after-free in crypt_message when using async crypto Date: Tue, 22 Jul 2025 10:19:11 -0400 Message-Id: <20250722141911.953243-1-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <2025072141-jujitsu-ebay-6dbf@gregkh> References: <2025072141-jujitsu-ebay-6dbf@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: Wang Zhaolong [ Upstream commit b220bed63330c0e1733dc06ea8e75d5b9962b6b6 ] The CVE-2024-50047 fix removed asynchronous crypto handling from crypt_message(), assuming all crypto operations are synchronous. However, when hardware crypto accelerators are used, this can cause use-after-free crashes: crypt_message() // Allocate the creq buffer containing the req creq = smb2_get_aead_req(..., &req); // Async encryption returns -EINPROGRESS immediately rc = enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req); // Free creq while async operation is still in progress kvfree_sensitive(creq, ...); Hardware crypto modules often implement async AEAD operations for performance. When crypto_aead_encrypt/decrypt() returns -EINPROGRESS, the operation completes asynchronously. Without crypto_wait_req(), the function immediately frees the request buffer, leading to crashes when the driver later accesses the freed memory. This results in a use-after-free condition when the hardware crypto driver later accesses the freed request structure, leading to kernel crashes with NULL pointer dereferences. The issue occurs because crypto_alloc_aead() with mask=0 doesn't guarantee synchronous operation. Even without CRYPTO_ALG_ASYNC in the mask, async implementations can be selected. Fix by restoring the async crypto handling: - DECLARE_CRYPTO_WAIT(wait) for completion tracking - aead_request_set_callback() for async completion notification - crypto_wait_req() to wait for operation completion This ensures the request buffer isn't freed until the crypto operation completes, whether synchronous or asynchronous, while preserving the CVE-2024-50047 fix. Fixes: b0abcd65ec54 ("smb: client: fix UAF in async decryption") Link: https://lore.kernel.org/all/8b784a13-87b0-4131-9ff9-7a8993538749@huaweicloud.com/ Cc: stable@vger.kernel.org Reviewed-by: Paulo Alcantara (Red Hat) Signed-off-by: Wang Zhaolong Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/smb2ops.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index aa1acc698caa2..1297acb5bf8e5 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -4302,6 +4302,7 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst, u8 key[SMB3_ENC_DEC_KEY_SIZE]; struct aead_request *req; u8 *iv; + DECLARE_CRYPTO_WAIT(wait); unsigned int crypt_len = le32_to_cpu(tr_hdr->OriginalMessageSize); void *creq; @@ -4350,7 +4351,11 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst, aead_request_set_crypt(req, sg, sg, crypt_len, iv); aead_request_set_ad(req, assoc_data_len); - rc = enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req); + aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, + crypto_req_done, &wait); + + rc = crypto_wait_req(enc ? crypto_aead_encrypt(req) + : crypto_aead_decrypt(req), &wait); if (!rc && enc) memcpy(&tr_hdr->Signature, sign, SMB2_SIGNATURE_SIZE); -- 2.39.5