[PATCH AUTOSEL 4.9 2/2] ntfs: add sanity check on allocation size

[Sasha Levin <sashal@kernel.org>]

From: Dongliang Mu <mudongliangabcd@gmail.com>

[ Upstream commit 714fbf2647b1a33d914edd695d4da92029c7e7c0 ]

ntfs_read_inode_mount invokes ntfs_malloc_nofs with zero allocation
size.  It triggers one BUG in the __ntfs_malloc function.

Fix this by adding sanity check on ni->attr_list_size.

Link: https://lkml.kernel.org/r/20220120094914.47736-1-dzm91@hust.edu.cn
Reported-by: syzbot+3c765c5248797356edaa@syzkaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ntfs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 8cd134750ebb..4150b3633f77 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1915,6 +1915,10 @@ int ntfs_read_inode_mount(struct inode *vi)
 		}
 		/* Now allocate memory for the attribute list. */
 		ni->attr_list_size = (u32)ntfs_attr_size(a);
+		if (!ni->attr_list_size) {
+			ntfs_error(sb, "Attr_list_size is zero");
+			goto put_err_out;
+		}
 		ni->attr_list = ntfs_malloc_nofs(ni->attr_list_size);
 		if (!ni->attr_list) {
 			ntfs_error(sb, "Not enough memory to allocate buffer "
-- 
2.34.1