From 2deb1acc653cbd5384b107d050d2deba089db2bd Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Wed, 30 Apr 2008 00:52:33 -0700
Subject: [PATCH] isofs: fix access to unallocated memory when reading
corrupted filesystem
When a directory on isofs is corrupted, we did not check whether length of the
name in a directory entry and the length of the directory entry itself are
consistent. This could lead to possible access beyond the end of buffer when
the length of the name was too big. Add this sanity check to directory
reading code.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/isofs/dir.c | 8 ++++++++
fs/isofs/namei.c | 7 +++++++
2 files changed, 15 insertions(+)
diff --git a/fs/isofs/dir.c b/fs/isofs/dir.c
index 1ba407c64df1..2f0dc5a14633 100644
--- a/fs/isofs/dir.c
+++ b/fs/isofs/dir.c
@@ -145,6 +145,14 @@ static int do_isofs_readdir(struct inode *inode, struct file *filp,
}
de = tmpde;
}
+ /* Basic sanity check, whether name doesn't exceed dir entry */
+ if (de_len < de->name_len[0] +
+ sizeof(struct iso_directory_record)) {
+ printk(KERN_NOTICE "iso9660: Corrupted directory entry"
+ " in block %lu of inode %lu\n", block,
+ inode->i_ino);
+ return -EIO;
+ }
if (first_de) {
isofs_normalize_block_and_offset(de,
diff --git a/fs/isofs/namei.c b/fs/isofs/namei.c
index 344b247bc29a..8299889a835e 100644
--- a/fs/isofs/namei.c
+++ b/fs/isofs/namei.c
@@ -111,6 +111,13 @@ isofs_find_entry(struct inode *dir, struct dentry *dentry,
dlen = de->name_len[0];
dpnt = de->name;
+ /* Basic sanity check, whether name doesn't exceed dir entry */
+ if (de_len < dlen + sizeof(struct iso_directory_record)) {
+ printk(KERN_NOTICE "iso9660: Corrupted directory entry"
+ " in block %lu of inode %lu\n", block,
+ dir->i_ino);
+ return 0;
+ }
if (sbi->s_rock &&
((i = get_rock_ridge_filename(de, tmpname, dir)))) {
--
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