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>
This commit is contained in:
Eric Sandeen 2007-10-16 23:27:15 -07:00 committed by Linus Torvalds
parent d8ea6cf899
commit f44ec6f3f8
2 changed files with 14 additions and 4 deletions

View file

@ -23,11 +23,16 @@ static inline block_t *i_data(struct inode *inode)
static int block_to_path(struct inode * inode, long block, int offsets[DEPTH])
{
int n = 0;
char b[BDEVNAME_SIZE];
if (block < 0) {
printk("minix_bmap: block<0\n");
printk("MINIX-fs: block_to_path: block %ld < 0 on dev %s\n",
block, bdevname(inode->i_sb->s_bdev, b));
} else if (block >= (minix_sb(inode->i_sb)->s_max_size/BLOCK_SIZE)) {
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(inode->i_sb->s_bdev, b));
} else if (block < 7) {
offsets[n++] = block;
} else if ((block -= 7) < 512) {

View file

@ -23,12 +23,17 @@ static inline block_t *i_data(struct inode *inode)
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) {