From ec06d480b2d14d2037e8cd68a960c4959d04197c Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 19 Dec 2014 12:21:47 +0100 Subject: [PATCH] udf: Verify symlink size before loading it commit a1d47b262952a45aae62bd49cfaf33dd76c11a2c upstream. 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. Reported-by: Carl Henrik Lunde Signed-off-by: Jan Kara Signed-off-by: Luis Henriques --- fs/udf/symlink.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c index ab94e66718497..2d0c3720e9afd 100644 --- a/fs/udf/symlink.c +++ b/fs/udf/symlink.c @@ -99,11 +99,17 @@ 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); @@ -113,8 +119,10 @@ 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; } @@ -130,9 +138,10 @@ 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; -- 2.47.3