linux-kernel - [PATCH 2.6.32 09/62] udf: Verify symlink size before loading it

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20150912225606.957401547@1wt.eu>
Date:	Sun, 13 Sep 2015 00:56:15 +0200
From:	Willy Tarreau <w@....eu>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Carl Henrik Lunde <chlunde@...il.com>, Jan Kara <jack@...e.cz>,
	Ben Hutchings <ben@...adent.org.uk>, Willy Tarreau <w@....eu>
Subject: [PATCH 2.6.32 09/62] udf: Verify symlink size before loading it

2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@...e.cz>

commit a1d47b262952a45aae62bd49cfaf33dd76c11a2c upstream.

UDF specification allows arbitrarily large symlinks. However we support
only symlinks at most one block large. Check the length of the symlink
so that we don't access memory beyond end of the symlink block.

Reported-by: Carl Henrik Lunde <chlunde@...il.com>
Signed-off-by: Jan Kara <jack@...e.cz>
[bwh: Backported to 2.6.32: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>

CVE-2014-9728

Signed-off-by: Willy Tarreau <w@....eu>
---
 fs/udf/symlink.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c
index c3265e1..e28a902 100644
--- a/fs/udf/symlink.c
+++ b/fs/udf/symlink.c
@@ -76,10 +76,16 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 	struct inode *inode = page->mapping->host;
 	struct buffer_head *bh = NULL;
 	char *symlink;
-	int err = -EIO;
+	int err;
 	char *p = kmap(page);
 	struct udf_inode_info *iinfo;
 
+	/* We don't support symlinks longer than one block */
+	if (inode->i_size > inode->i_sb->s_blocksize) {
+		err = -ENAMETOOLONG;
+		goto out_unmap;
+	}
+
 	lock_kernel();
 	iinfo = UDF_I(inode);
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
@@ -87,8 +93,10 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 	} else {
 		bh = sb_bread(inode->i_sb, udf_block_map(inode, 0));
 
-		if (!bh)
-			goto out;
+		if (!bh) {
+			err = -EIO;
+			goto out_unlock_inode;
+		}
 
 		symlink = bh->b_data;
 	}
@@ -102,9 +110,10 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 	unlock_page(page);
 	return 0;
 
-out:
+out_unlock_inode:
 	unlock_kernel();
 	SetPageError(page);
+out_unmap:
 	kunmap(page);
 	unlock_page(page);
 	return err;
-- 
1.7.12.2.21.g234cd45.dirty



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/