Re: Two vulnerabilities are founded,please confirm.

From: Samuel Tardieu
Date: Tue Sep 12 2006 - 12:04:14 EST


>>>>> "Sam" == Samuel Tardieu <sam@xxxxxxxxxxx> writes:

Sam> Would a simple fix like this one (untested) work?

Or rather (less likely to be in the path by putting it in
__find_get_block_slow):

Check that the requested block fits in the device.

Fix for advisory AD_LAB-06011 Linux kernel Filesystem Mount Dead Loop.

Signed-off-by: Samuel Tardieu <sam@xxxxxxxxxxx>

diff -r db51efd75e66 fs/buffer.c
--- a/fs/buffer.c Sun Sep 10 01:02:33 2006 +0200
+++ b/fs/buffer.c Tue Sep 12 18:01:37 2006 +0200
@@ -393,6 +393,14 @@ __find_get_block_slow(struct block_devic
struct buffer_head *head;
struct page *page;
int all_mapped = 1;
+ char b[BDEVNAME_SIZE];
+
+ if (block >= bdev->bd_disk->capacity) {
+ printk(KERN_ERR "Invalid block number %Ld requested on device %s",
+ (unsigned long long)block,
+ bdevname(bdev, b));
+ return NULL;
+ }

index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits);
page = find_get_page(bd_mapping, index);

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