limit minixfs printks on corrupted dir i_size (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.

Adrian Bunk:
Backported to 2.6.16.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

diff --git a/fs/minix/itree_v1.c b/fs/minix/itree_v1.c
index 656b1347a25bee35577d0d2cb73a190f9f3adac2..2f167044d6c027cd5238b4bc3c4a8cc3c06d842b 100644 (file)
--- a/fs/minix/itree_v1.c
+++ b/fs/minix/itree_v1.c
@@ -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) {

diff --git a/fs/minix/itree_v2.c b/fs/minix/itree_v2.c
index 9adcdc754e0fc2da58b7496b472789d41a910445..65f74d4db931427c4d0a5938e9ad342435f99a6a 100644 (file)
--- a/fs/minix/itree_v2.c
+++ b/fs/minix/itree_v2.c
@@ -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) < 256) {