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From: Vivek Goyal <>
Subject: [PATCH v2 2/6] fuse: Set FUSE_WRITE_KILL_PRIV in cached write path
Date: Wed, 16 Sep 2020 12:17:33 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

With HANDLE_KILLPRIV_V2, server will need to kill suid/sgid if caller
does not have CAP_FSETID. We already have a flag FUSE_WRITE_KILL_PRIV
in WRITE request and we already set it in direct I/O path.

To make it work in cached write path also, start setting FUSE_WRITE_KILL_PRIV
in this path too.

Set it only if fc->handle_killpriv_v2 is set. Otherwise client is responsible
for kill suid/sgid.

In case of direct I/O we set FUSE_WRITE_KILL_PRIV unconditionally because
we do't call file_remove_privs() in that path (with cache=none option).

Signed-off-by: Vivek Goyal <>
 fs/fuse/file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 172a0b1aa634..e40428f3d0f1 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1095,6 +1095,8 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
 	fuse_write_args_fill(ia, ff, pos, count);
 	ia-> = fuse_write_flags(iocb);
+	if (fc->handle_killpriv_v2 && !capable(CAP_FSETID))
 	err = fuse_simple_request(fc, &ap->args);
 	if (!err && ia->write.out.size > count)

  parent reply	other threads:[~2020-09-16 20:50 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-16 16:17 [PATCH v2 0/6] fuse: Implement FUSE_HANDLE_KILLPRIV_V2 and enable SB_NOSEC Vivek Goyal
2020-09-16 16:17 ` [PATCH v2 1/6] fuse: Introduce the notion of FUSE_HANDLE_KILLPRIV_V2 Vivek Goyal
2020-09-16 16:17 ` Vivek Goyal [this message]
2020-09-16 16:17 ` [PATCH v2 3/6] fuse: setattr should set FATTR_KILL_PRIV upon size change Vivek Goyal
2020-09-16 16:17 ` [PATCH v2 4/6] fuse: Kill suid/sgid using ATTR_MODE if it is not truncate Vivek Goyal
2020-09-22 13:56   ` Miklos Szeredi
2020-09-22 20:08     ` Vivek Goyal
2020-09-22 21:25       ` Miklos Szeredi
2020-09-22 21:31         ` Vivek Goyal
2020-09-16 16:17 ` [PATCH v2 5/6] fuse: Add a flag FUSE_OPEN_KILL_PRIV for open() request Vivek Goyal
2020-09-16 16:17 ` [PATCH v2 6/6] virtiofs: Support SB_NOSEC flag to improve direct write performance Vivek Goyal
2020-09-16 16:38 ` [PATCH v2 0/6] fuse: Implement FUSE_HANDLE_KILLPRIV_V2 and enable SB_NOSEC Vivek Goyal

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