-stable review patch. If anyone has any objections, please let us know. ------------------
From: Phillip Lougher <[EMAIL PROTECTED]> 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. Signed-off-by: Phillip Lougher <[EMAIL PROTECTED]> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]> Signed-off-by: Chris Wright <[EMAIL PROTECTED]> --- Date: Thu, 7 Dec 2006 04:37:20 +0000 (-0800) Subject: [patch 31/50] [PATCH] corrupted cramfs filesystems cause kernel oops X-Git-Tag: v2.6.20-rc1 X-Git-Url: http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8bb0269160df2a60764013994d0bc5165406cf4a fs/cramfs/inode.c | 2 ++ 1 file changed, 2 insertions(+) --- linux-2.6.19.1.orig/fs/cramfs/inode.c +++ linux-2.6.19.1/fs/cramfs/inode.c @@ -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 [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
