Thread (5 messages) 5 messages, 4 authors, 2021-07-22

Re: [PATCH v4] fs: forbid invalid project ID

From: "Darrick J. Wong" <djwong@kernel.org>
Date: 2021-07-14 05:04:38
Also in: linux-f2fs-devel, linux-fsdevel, linux-xfs

On Sat, Jul 10, 2021 at 10:39:59PM +0800, Wang Shilong wrote:
quoted hunk ↗ jump to hunk
From: Wang Shilong <redacted>

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>
---
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;
Hmm, for XFS this is sort of a userspace-breaking change in the sense
that (technically) we've never rejected -1 before.  xfs_quota won't have
anything to do with that, and (assuming I read the helper/macro
gooeyness correctly) the vfs quota code won't either, so

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D
 	}
 
 	/* Check extent size hints. */
-- 
2.27.0
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