linux-kernel - [PATCH V5] squashfs: Add i_size check in squash_read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240802111640.2762325-1-lizhi.xu@windriver.com>
Date: Fri, 2 Aug 2024 19:16:40 +0800
From: Lizhi Xu <lizhi.xu@...driver.com>
To: <jack@...e.cz>
CC: <brauner@...nel.org>, <linux-fsdevel@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <lizhi.xu@...driver.com>,
        <phillip@...ashfs.org.uk>, <squashfs-devel@...ts.sourceforge.net>,
        <syzbot+24ac24ff58dc5b0d26b9@...kaller.appspotmail.com>,
        <syzkaller-bugs@...glegroups.com>, <viro@...iv.linux.org.uk>
Subject: [PATCH V5] squashfs: Add i_size check in squash_read_inode

syzbot report KMSAN: uninit-value in pick_link, the root cause is that
squashfs_symlink_read_folio did not check the length, resulting in folio
not being initialized and did not return the corresponding error code.

The length is calculated from i_size, so it is necessary to add a check
when i_size is initialized to confirm that its value is correct, otherwise
an error -EINVAL will be returned. Strictly, the check only applies to the
symlink type. Add larger symlink check.

Reported-and-tested-by: syzbot+24ac24ff58dc5b0d26b9@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=24ac24ff58dc5b0d26b9
Signed-off-by: Lizhi Xu <lizhi.xu@...driver.com>
---
 fs/squashfs/inode.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c
index 16bd693d0b3a..6c5dd225482f 100644
--- a/fs/squashfs/inode.c
+++ b/fs/squashfs/inode.c
@@ -287,6 +287,11 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 		inode->i_mode |= S_IFLNK;
 		squashfs_i(inode)->start = block;
 		squashfs_i(inode)->offset = offset;
+		if ((int)inode->i_size < 0 || inode->i_size > PAGE_SIZE) {
+			ERROR("Wrong i_size %d!\n", inode->i_size);
+			return -EINVAL;
+		}
+
 
 		if (type == SQUASHFS_LSYMLINK_TYPE) {
 			__le32 xattr;
-- 
2.43.0