On Tue, Jun 29, 2021 at 6:34 AM Dave Chinner [off-list ref] wrote:

On Mon, Jun 28, 2021 at 08:38:01AM -0400, Wang Shilong wrote:

quoted

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 <redacted>
---
v1->v2: try to fix in the VFS
---
 fs/ioctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 1e2204fa9963..5db5b218637b 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c

@@ -845,6 +845,9 @@ static int fileattr_set_prepare(struct inode *inode,
      if (fa->fsx_cowextsize == 0)
              fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;

+     if (!projid_valid(KPROJIDT_INIT(fa->fsx_projid)))
+             return -EINVAL;

This needs to go further up in this function in the section where
project IDs passed into this function are validated. Projids are
only allowed to be changed when current_user_ns() == &init_user_ns,
so this needs to be associated with that verification context.

This check should also use make_kprojid(), please, not open code
KPROJIDT_INIT.

You are right, let me send a V3

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com