From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0134.outbound.protection.outlook.com ([104.47.42.134]:46538 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753479AbeA1W1l (ORCPT ); Sun, 28 Jan 2018 17:27:41 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Eric Biggers , Eric Biggers , David Howells , Sasha Levin Subject: [PATCH AUTOSEL for 4.14 070/100] 509: fix printing uninitialized stack memory when OID is empty Date: Sun, 28 Jan 2018 22:26:44 +0000 Message-ID: <20180128222547.7398-70-alexander.levin@microsoft.com> References: <20180128222547.7398-1-alexander.levin@microsoft.com> In-Reply-To: <20180128222547.7398-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Eric Biggers [ Upstream commit 8dfd2f22d3bf3ab7714f7495ad5d897b8845e8c1 ] Callers of sprint_oid() do not check its return value before printing the result. In the case where the OID is zero-length, -EBADMSG was being returned without anything being written to the buffer, resulting in uninitialized stack memory being printed. Fix this by writing "(bad)" to the buffer in the cases where -EBADMSG is returned. Fixes: 4f73175d0375 ("X.509: Add utility functions to render OIDs as string= s") Signed-off-by: Eric Biggers Signed-off-by: David Howells Signed-off-by: Sasha Levin --- lib/oid_registry.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/oid_registry.c b/lib/oid_registry.c index 41b9e50711a7..b5f7d9986be1 100644 --- a/lib/oid_registry.c +++ b/lib/oid_registry.c @@ -116,7 +116,7 @@ int sprint_oid(const void *data, size_t datasize, char = *buffer, size_t bufsize) int count; =20 if (v >=3D end) - return -EBADMSG; + goto bad; =20 n =3D *v++; ret =3D count =3D snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40); @@ -134,7 +134,7 @@ int sprint_oid(const void *data, size_t datasize, char = *buffer, size_t bufsize) num =3D n & 0x7f; do { if (v >=3D end) - return -EBADMSG; + goto bad; n =3D *v++; num <<=3D 7; num |=3D n & 0x7f; @@ -148,6 +148,10 @@ int sprint_oid(const void *data, size_t datasize, char= *buffer, size_t bufsize) } =20 return ret; + +bad: + snprintf(buffer, bufsize, "(bad)"); + return -EBADMSG; } EXPORT_SYMBOL_GPL(sprint_oid); =20 --=20 2.11.0