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From:   Dongliang Mu <dzm91@hust.edu.cn>
To:     Anton Altaparmakov <anton@tuxera.com>
Cc:     Dongliang Mu <mudongliangabcd@gmail.com>,
        syzbot+3c765c5248797356edaa@syzkaller.appspotmail.com,
        linux-ntfs-dev@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: [PATCH] ntfs: add sanity check on allocation size
Date:   Thu, 20 Jan 2022 17:49:14 +0800
Message-Id: <20220120094914.47736-1-dzm91@hust.edu.cn>
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From: Dongliang Mu <mudongliangabcd@gmail.com>

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.

Reported-by: syzbot+3c765c5248797356edaa@syzkaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
 fs/ntfs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 4474adb393ca..517b71c73aa9 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -1881,6 +1881,10 @@ 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 "
-- 
2.25.1