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 <[email protected]> Cc: Bodo Eggert <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
Baughn · Oct 17, 2007 · f44ec6f · f44ec6f
1 parent d8ea6cf
commit f44ec6f
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git 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
@@ -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) {