aha/fs/minix/itree_v2.c
Eric Sandeen f44ec6f3f8 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>
2007-10-17 08:42:53 -07:00

72 lines
1.6 KiB
C

#include <linux/buffer_head.h>
#include "minix.h"
enum {DIRECT = 7, DEPTH = 4}; /* Have triple indirect */
typedef u32 block_t; /* 32 bit, host order */
static inline unsigned long block_to_cpu(block_t n)
{
return n;
}
static inline block_t cpu_to_block(unsigned long n)
{
return n;
}
static inline block_t *i_data(struct inode *inode)
{
return (block_t *)minix_i(inode)->u.i2_data;
}
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-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)) {
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) {
offsets[n++] = 7;
offsets[n++] = block;
} else if ((block -= 256) < 256*256) {
offsets[n++] = 8;
offsets[n++] = block>>8;
offsets[n++] = block & 255;
} else {
block -= 256*256;
offsets[n++] = 9;
offsets[n++] = block>>16;
offsets[n++] = (block>>8) & 255;
offsets[n++] = block & 255;
}
return n;
}
#include "itree_common.c"
int V2_minix_get_block(struct inode * inode, long block,
struct buffer_head *bh_result, int create)
{
return get_block(inode, block, bh_result, create);
}
void V2_minix_truncate(struct inode * inode)
{
truncate(inode);
}
unsigned V2_minix_blocks(loff_t size, struct super_block *sb)
{
return nblocks(size, sb);
}