fs/ntfs3: Validate attribute data and valid sizes

commit 019d22eb0eb707fc099e6e8fad9b3933236a06d0 upstream.

The data_size and valid_size fields of non resident attributes should be
less than the its alloc_size field, but this is not checked in
ntfs_read_mft function.

Syzbot reports a allocation order warning due to a large unchecked value
of data_size getting assigned to inode->i_size which is then passed to
kcalloc.

Add sanity check for ensuring that the data_size and valid_size fields
are not larger than alloc_size field.

Link: https://syzkaller.appspot.com/bug?extid=fa4648a5446460b7b963
Reported-and-tested-by: syzbot+fa4648a5446460b7b963@syzkaller.appspotmail.com
Fixes: (82cae269cfa95) fs/ntfs3: Add initialization of super block
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index e352aa3..2215230 100644 (file)
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -132,6 +132,13 @@ next_attr:
        if (le16_to_cpu(attr->name_off) + attr->name_len > asize)
                goto out;
 
+       if (attr->non_res) {
+               t64 = le64_to_cpu(attr->nres.alloc_size);
+               if (le64_to_cpu(attr->nres.data_size) > t64 ||
+                   le64_to_cpu(attr->nres.valid_size) > t64)
+                       goto out;
+       }
+
        switch (attr->type) {
        case ATTR_STD:
                if (attr->non_res ||