limit minixfs printks on corrupted dir i_size
This attempts to address CVE-2006-6058
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-6058
first reported at http://projects.info-pull.com/mokb/MOKB-17-11-2006.html
Essentially a corrupted minix dir inode reporting a very large
i_size will loop for a very long time in minix_readdir, minix_find_entry,
etc, because on EIO they just move on to try the next page. This is
under the BKL, printk-storming as well. This can lock up the machine
for a very long time. Simply ratelimiting the printks gets things back
under control. Make the message a bit more informative while we're here.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Bodo Eggert <7eggert@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/minix/itree_v2.c b/fs/minix/itree_v2.c
index ad8f0de..f230109 100644
--- a/fs/minix/itree_v2.c
+++ b/fs/minix/itree_v2.c
@@ -23,12 +23,17 @@
static int block_to_path(struct inode * inode, long block, int offsets[DEPTH])
{
int n = 0;
+ char b[BDEVNAME_SIZE];
struct super_block *sb = inode->i_sb;
if (block < 0) {
- printk("minix_bmap: block<0\n");
+ printk("MINIX-fs: block_to_path: block %ld < 0 on dev %s\n",
+ block, bdevname(sb->s_bdev, b));
} else if (block >= (minix_sb(inode->i_sb)->s_max_size/sb->s_blocksize)) {
- printk("minix_bmap: block>big\n");
+ if (printk_ratelimit())
+ printk("MINIX-fs: block_to_path: "
+ "block %ld too big on dev %s\n",
+ block, bdevname(sb->s_bdev, b));
} else if (block < 7) {
offsets[n++] = block;
} else if ((block -= 7) < 256) {