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
| ||
|
Date: Sun, 5 Nov 2006 04:02:00 +0000 From: Phillip Lougher <phillip@...gher.org.uk> To: linux-kernel@...r.kernel.org Cc: akpm@...l.org Subject: [PATCH] corrupted cramfs filesystems cause kernel oops Steve Grubb's fzfuzzer tool (http://people.redhat.com/sgrubb/files/ fsfuzzer-0.6.tar.gz) generates corrupt Cramfs filesystems which cause Cramfs to kernel oops in cramfs_uncompress_block(). The cause of the oops is an unchecked corrupted block length field read by cramfs_readpage(). This patch adds a sanity check to cramfs_readpage() which checks that the block length field is sensible. The (PAGE_CACHE_SIZE << 1) size check is intentional, even though the uncompressed data is not going to be larger than PAGE_CACHE_SIZE, gzip sometimes generates compressed data larger than the original source data. Mkcramfs checks that the compressed size is always less than or equal to PAGE_CACHE_SIZE << 1. Of course Cramfs could use the original uncompressed data in this case, but it doesn't. Patch is against 2.6.19-rc4. Signed-off-by: Phillip Lougher <phillip <at> lougher.org.uk> diff -Nurp a/fs/cramfs/inode.c b/fs/cramfs/inode.c --- a/fs/cramfs/inode.c 2006-11-05 00:59:53.000000000 +0000 +++ b/fs/cramfs/inode.c 2006-11-05 03:17:43.000000000 +0000 @@ -481,6 +481,8 @@ static int cramfs_readpage(struct file * pgdata = kmap(page); if (compr_len == 0) ; /* hole */ + else if (compr_len > (PAGE_CACHE_SIZE << 1)) + printk(KERN_ERR "cramfs: bad compressed blocksize %u\n", compr_len); else { mutex_lock(&read_mutex); bytes_filled = cramfs_uncompress_block(pgdata, - 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/
Powered by blists - more mailing lists