From 41ba2abbb3ce394c208fe509438a4691d588ad94 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 19 Dec 2014 14:27:55 +0100 Subject: udf: Check component length before reading it 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: Greg Kroah-Hartman --- fs/udf/symlink.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c index 0f1b3a2654b9..ac10ca939f26 100644 --- a/fs/udf/symlink.c +++ b/fs/udf/symlink.c @@ -42,14 +42,17 @@ static int udf_pc_to_char(struct super_block *sb, unsigned char *from, 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_block *sb, unsigned char *from, /* 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_block *sb, unsigned char *from, tolen--; break; } - elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; } if (p > to + 1) p[-1] = '\0'; -- cgit v1.2.3