From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3281902-1517861000-2-2302998398810992546 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES unknown, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1517860999; b=uRHtm66IJLrscqpxETWJ2cRPYMwMHGvRVx7oUZt0kly7zHD OgJCy+LMQs4/C2oZhh4wm3BbiU2wSGG87Lv3n0Ovr4RLAWqplKiygJ9fXyu/CmLO fsAX21nSf3ZP5veNCEODSYN3+2b+hGDs6avO5vnCHx2zHtu6XzQtCQgRsa9qygzR BYL3lTAO0biZsI/HoDT3hBIcIv0xhyTrpxWwepGoFDhcYc+Rsi/K/teDue/E/eLA HpwJMGVEqs83buzpYlY59dV3o4O6dl1jforAXFYKGGQK8HzPDU8PQb3c10YMUTwe pLOVFM4yT1rrJlkMprzkDURR6B2ROo2CUg41mVg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id:sender :list-id; s=arctest; t=1517860999; bh=8ZB65BZPe50/BHY876N4JslTJN qTT5A2Tmwyd0OK2cM=; b=Olsh7ecQP8hglvTVkLJNz9SQY5HVHwX6QS3jd9mGXc ksZDfysyuTDN07q6DX5qVSO1mfxUw8t0bVj7+eYzvNBu8TZK1XmIOFIzyIByKMbh lBtAYXpgVotDnjxHOOyXudTIS/sx5AJ1bSe6tFJFz1mCWYcpvVcffPCDdMzZoeWO TqRSTKVXbhmcz1LTt2A72mBggucw/bmxviR+yfKeh12ZRAT4savS1PpN3v0pOs4u wSSgkRDct390emm2O2PIYxisj2+RnrQIqE/72Cz3NvgtO1o1sHrULE9B9EV7p+XS kcmNLWungT7IBPhxP8ZDOtSfRui7Stb6vxC/8+FxEYFw== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=android.com header.i=@android.com header.b=HeHkKh85 x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=android.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=PoNInVo5; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=android.com header.result=pass header_is_org_domain=yes Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=android.com header.i=@android.com header.b=HeHkKh85 x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=android.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=PoNInVo5; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=android.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751625AbeBEUDD (ORCPT ); Mon, 5 Feb 2018 15:03:03 -0500 Received: from mail-pg0-f65.google.com ([74.125.83.65]:40723 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751236AbeBEUDB (ORCPT ); Mon, 5 Feb 2018 15:03:01 -0500 X-Google-Smtp-Source: AH8x226GPNCv1qoz8EYZJEuTx4oyA/EQZLgqkw4U1kHsDZ6+IOJPIUk/lIZSpFcpu/E0oiZfYBt/rA== From: Jin Qian To: Mimi Zohar , David Safford , David Howells , James Morris , "Serge E. Hallyn" , linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Eric Biggers , stable@vger.kernel.org, Jin Qian Subject: [PATCH 1/1] KEYS: encrypted: fix buffer overread in valid_master_desc() Date: Mon, 5 Feb 2018 12:02:46 -0800 Message-Id: <20180205200246.12253-1-jinqian@android.com> X-Mailer: git-send-email 2.16.0.rc1.238.g530d649a79-goog Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Eric Biggers commit 794b4bc292f5d31739d89c0202c54e7dc9bc3add upstream With the 'encrypted' key type it was possible for userspace to provide a data blob ending with a master key description shorter than expected, e.g. 'keyctl add encrypted desc "new x" @s'. When validating such a master key description, validate_master_desc() could read beyond the end of the buffer. Fix this by using strncmp() instead of memcmp(). [Also clean up the code to deduplicate some logic.] Cc: stable@vger.kernel.org Cc: Mimi Zohar Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Jin Qian --- security/keys/encrypted-keys/encrypted.c | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index a871159bf03c..ead2fd60244d 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -141,23 +141,22 @@ static int valid_ecryptfs_desc(const char *ecryptfs_desc) */ static int valid_master_desc(const char *new_desc, const char *orig_desc) { - if (!memcmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) { - if (strlen(new_desc) == KEY_TRUSTED_PREFIX_LEN) - goto out; - if (orig_desc) - if (memcmp(new_desc, orig_desc, KEY_TRUSTED_PREFIX_LEN)) - goto out; - } else if (!memcmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) { - if (strlen(new_desc) == KEY_USER_PREFIX_LEN) - goto out; - if (orig_desc) - if (memcmp(new_desc, orig_desc, KEY_USER_PREFIX_LEN)) - goto out; - } else - goto out; + int prefix_len; + + if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) + prefix_len = KEY_TRUSTED_PREFIX_LEN; + else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) + prefix_len = KEY_USER_PREFIX_LEN; + else + return -EINVAL; + + if (!new_desc[prefix_len]) + return -EINVAL; + + if (orig_desc && strncmp(new_desc, orig_desc, prefix_len)) + return -EINVAL; + return 0; -out: - return -EINVAL; } /* -- 2.16.0.rc1.238.g530d649a79-goog