[PATCH v4] fs: forbid invalid project ID

From: Wang Shilong <wangshilong1991@gmail.com>
To: linux-fsdevel@vger.kernel.org
Cc: linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	Wang Shilong <wshilong@ddn.com>
Subject: [PATCH v4] fs: forbid invalid project ID
Date: Sat, 10 Jul 2021 22:39:59 +0800	[thread overview]
Message-ID: <20210710143959.58077-1-wangshilong1991@gmail.com> (raw)

From: Wang Shilong <wshilong@ddn.com>

fileattr_set_prepare() should check if project ID
is valid, otherwise dqget() will return NULL for
such project ID quota.

Signed-off-by: Wang Shilong <wshilong@ddn.com>
---
v3->v3:
only check project Id if caller is allowed
to change and being changed.

v2->v3: move check before @fsx_projid is accessed
and use make_kprojid() helper.

v1->v2: try to fix in the VFS
 fs/ioctl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 1e2204fa9963..d4fabb5421cd 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -817,6 +817,14 @@ static int fileattr_set_prepare(struct inode *inode,
 		if ((old_ma->fsx_xflags ^ fa->fsx_xflags) &
 				FS_XFLAG_PROJINHERIT)
 			return -EINVAL;
+	} else {
+		/*
+		 * Caller is allowed to change the project ID. If it is being
+		 * changed, make sure that the new value is valid.
+		 */
+		if (old_ma->fsx_projid != fa->fsx_projid &&
+		    !projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid)))
+			return -EINVAL;
 	}
 
 	/* Check extent size hints. */
-- 
2.27.0

