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Commit a1d47b26 authored by Jan Kara's avatar Jan Kara
Browse files

udf: Verify symlink size before loading it 



UDF specification allows arbitrarily large symlinks. However we support
only symlinks at most one block large. Check the length of the symlink
so that we don't access memory beyond end of the symlink block.

CC: stable@vger.kernel.org
Reported-by: default avatarCarl Henrik Lunde <chlunde@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent e159332b

fs/udf/symlink.c

+13 −4
Original line number Diff line number Diff line
@@ -80,11 +80,17 @@ static int udf_symlink_filler(struct file *file, struct page *page) 
	struct inode *inode = page->mapping->host;

	struct buffer_head *bh = NULL;

	unsigned char *symlink;

	int err = -EIO;

	int err;

	unsigned char *p = kmap(page);

	struct udf_inode_info *iinfo;

	uint32_t pos;



	/* We don't support symlinks longer than one block */

	if (inode->i_size > inode->i_sb->s_blocksize) {

		err = -ENAMETOOLONG;

		goto out_unmap;

	}



	iinfo = UDF_I(inode);

	pos = udf_block_map(inode, 0);
@@ -94,8 +100,10 @@ static int udf_symlink_filler(struct file *file, struct page *page) 
	} else {

		bh = sb_bread(inode->i_sb, pos);



		if (!bh)

			goto out;

		if (!bh) {

			err = -EIO;

			goto out_unlock_inode;

		}



		symlink = bh->b_data;

	}
@@ -109,9 +117,10 @@ static int udf_symlink_filler(struct file *file, struct page *page) 
	unlock_page(page);

	return 0;



out:

out_unlock_inode:

	up_read(&iinfo->i_data_sem);

	SetPageError(page);

out_unmap:

	kunmap(page);

	unlock_page(page);

	return err;