patch-2.3.4 linux/mm/swapfile.c

• Lines: 87
• Date: Fri May 28 15:52:46 1999
• Orig file: v2.3.3/linux/mm/swapfile.c
• Orig date: Mon May 17 09:55:23 1999

diff -u --recursive --new-file v2.3.3/linux/mm/swapfile.c linux/mm/swapfile.c
@@ -503,7 +503,9 @@
 	int swap_header_version;
 	int lock_map_size = PAGE_SIZE;
 	int nr_good_pages = 0;
+	unsigned long maxpages;
 	unsigned long tmp_lock_map = 0;
+	int swapfilesize;
 	
 	lock_kernel();
 	if (!capable(CAP_SYS_ADMIN))
@@ -542,27 +544,32 @@
 	error = -EINVAL;
 
 	if (S_ISBLK(swap_dentry->d_inode->i_mode)) {
-		p->swap_device = swap_dentry->d_inode->i_rdev;
-		set_blocksize(p->swap_device, PAGE_SIZE);
+		kdev_t dev = swap_dentry->d_inode->i_rdev;
+
+		p->swap_device = dev;
+		set_blocksize(dev, PAGE_SIZE);
 		
 		filp.f_dentry = swap_dentry;
 		filp.f_mode = 3; /* read write */
 		error = blkdev_open(swap_dentry->d_inode, &filp);
 		if (error)
 			goto bad_swap_2;
-		set_blocksize(p->swap_device, PAGE_SIZE);
+		set_blocksize(dev, PAGE_SIZE);
 		error = -ENODEV;
-		if (!p->swap_device ||
-		    (blk_size[MAJOR(p->swap_device)] &&
-		     !blk_size[MAJOR(p->swap_device)][MINOR(p->swap_device)]))
+		if (!dev || (blk_size[MAJOR(dev)] &&
+		     !blk_size[MAJOR(dev)][MINOR(dev)]))
 			goto bad_swap;
 		error = -EBUSY;
 		for (i = 0 ; i < nr_swapfiles ; i++) {
 			if (i == type)
 				continue;
-			if (p->swap_device == swap_info[i].swap_device)
+			if (dev == swap_info[i].swap_device)
 				goto bad_swap;
 		}
+		swapfilesize = 0;
+		if (blk_size[MAJOR(dev)])
+			swapfilesize = blk_size[MAJOR(dev)][MINOR(dev)]
+				/ (PAGE_SIZE / 1024);
 	} else if (S_ISREG(swap_dentry->d_inode->i_mode)) {
 		error = -EBUSY;
 		for (i = 0 ; i < nr_swapfiles ; i++) {
@@ -571,6 +578,7 @@
 			if (swap_dentry->d_inode == swap_info[i].swap_file->d_inode)
 				goto bad_swap;
 		}
+		swapfilesize = swap_dentry->d_inode->i_size / PAGE_SIZE;
 	} else
 		goto bad_swap;
 
@@ -639,11 +647,13 @@
 		p->highest_bit = swap_header->info.last_page - 1;
 		p->max	       = swap_header->info.last_page;
 
+		maxpages = SWP_OFFSET(SWP_ENTRY(0,~0UL));
+		if (p->max >= maxpages)
+			p->max = maxpages-1;
+
 		error = -EINVAL;
 		if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
 			goto bad_swap;
-		if (p->max >= SWP_OFFSET(SWP_ENTRY(0,~0UL)))
-			goto bad_swap;
 		
 		/* OK, set up the swap map and apply the bad block list */
 		if (!(p->swap_map = vmalloc (p->max * sizeof(short)))) {
@@ -666,6 +676,12 @@
 			goto bad_swap;
 	}
 	
+	if (swapfilesize && p->max > swapfilesize) {
+		printk(KERN_WARNING
+		       "Swap area shorter than signature indicates\n");
+		error = -EINVAL;
+		goto bad_swap;
+	}
 	if (!nr_good_pages) {
 		printk(KERN_WARNING "Empty swap-file\n");
 		error = -EINVAL;