From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jan Kara" , "Carl Henrik Lunde" Date: Tue, 17 Feb 2015 01:46:53 +0000 Message-ID: Subject: [PATCH 3.2 072/152] udf: Check component length before reading it In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit e237ec37ec154564f8690c5bd1795339955eeef9 upstream. Check that length specified in a component of a symlink fits in the input buffer we are reading. Also properly ignore component length for component types that do not use it. Otherwise we read memory after end of buffer for corrupted udf image. Reported-by: Carl Henrik Lunde Signed-off-by: Jan Kara Signed-off-by: Ben Hutchings --- fs/udf/symlink.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/fs/udf/symlink.c +++ b/fs/udf/symlink.c @@ -42,14 +42,17 @@ static int udf_pc_to_char(struct super_b tolen--; while (elen < fromlen) { pc = (struct pathComponent *)(from + elen); + elen += sizeof(struct pathComponent); switch (pc->componentType) { case 1: /* * Symlink points to some place which should be agreed * upon between originator and receiver of the media. Ignore. */ - if (pc->lengthComponentIdent > 0) + if (pc->lengthComponentIdent > 0) { + elen += pc->lengthComponentIdent; break; + } /* Fall through */ case 2: if (tolen == 0) @@ -74,6 +77,9 @@ static int udf_pc_to_char(struct super_b /* that would be . - just ignore */ break; case 5: + elen += pc->lengthComponentIdent; + if (elen > fromlen) + return -EIO; comp_len = udf_get_filename(sb, pc->componentIdent, pc->lengthComponentIdent, p, tolen); @@ -85,7 +91,6 @@ static int udf_pc_to_char(struct super_b tolen--; break; } - elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; } if (p > to + 1) p[-1] = '\0';