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authorJan Kara <jack@suse.cz>2014-12-19 12:21:47 +0100
committerJan Kara <jack@suse.cz>2014-12-19 13:17:10 +0100
commita1d47b262952a45aae62bd49cfaf33dd76c11a2c (patch)
tree92c3c45e582c0fb7f160ecfd0126dc6a612a879b
parente159332b9af4b04d882dbcfe1bb0117f0a6d4b58 (diff)
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: Carl Henrik Lunde <chlunde@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/udf/symlink.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c
index 6fb7945c1e6e..c3aa6fafd6cf 100644
--- a/fs/udf/symlink.c
+++ b/fs/udf/symlink.c
@@ -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;