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authorJan Kara <jack@suse.cz>2014-12-19 14:27:55 +0100
committerBen Hutchings <ben@decadent.org.uk>2015-02-20 00:49:32 +0000
commit1e21fa3ab68b261aa6086c49567963f6f3ad87b9 (patch)
tree8580307c2d0ebf6a9b46f195bacab12cff885f4d /fs
parentba4055175ea39c9f0c16da025c908d3049d2f791 (diff)
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 <chlunde@ping.uio.no> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/udf/symlink.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c
index 2d0c3720e9af..0422b7b8369f 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';