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authorJan Kara <jack@suse.cz>2014-12-19 12:21:47 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-08 10:30:29 -0800
commit53fbe4cb776d0d4ec981c0b1a9b0eca1c06d7753 (patch)
treeb15e5a39ea26cd6daa2e4026e615b18195a511d8
parenta6a4afa5c41f299404424cc55fa26611751bf38d (diff)
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 <chlunde@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 d6862e255f88..0f1b3a2654b9 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;