From 02f92b3868a1b34ab98464e76b0e4e060474ba10 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:22 +0100 Subject: fs: add file and path permissions helpers Add two simple helpers to check permissions on a file and path respectively and convert over some callers. It simplifies quite a few codepaths and also reduces the churn in later patches quite a bit. Christoph also correctly points out that this makes codepaths (e.g. ioctls) way easier to follow that would otherwise have to do more complex argument passing than necessary. Link: https://lore.kernel.org/r/20210121131959.646623-4-christian.brauner@ubuntu.com Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Reviewed-by: James Morris Signed-off-by: Christian Brauner --- net/unix/af_unix.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 41c3303c3357..18453d15dddf 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -936,7 +936,7 @@ static struct sock *unix_find_other(struct net *net, if (err) goto fail; inode = d_backing_inode(path.dentry); - err = inode_permission(inode, MAY_WRITE); + err = path_permission(&path, MAY_WRITE); if (err) goto put_fail; -- cgit From 6521f8917082928a4cb637eb64b77b5f2f5b30fc Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:33 +0100 Subject: namei: prepare for idmapped mounts The various vfs_*() helpers are called by filesystems or by the vfs itself to perform core operations such as create, link, mkdir, mknod, rename, rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace and pass it down. Afterwards the checks and operations are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-15-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- net/unix/af_unix.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 18453d15dddf..9a1f3c04402e 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -996,7 +996,8 @@ static int unix_mknod(const char *sun_path, umode_t mode, struct path *res) */ err = security_path_mknod(&path, dentry, mode, 0); if (!err) { - err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0); + err = vfs_mknod(&init_user_ns, d_inode(path.dentry), dentry, + mode, 0); if (!err) { res->mnt = mntget(path.mnt); res->dentry = dget(dentry); -- cgit From 7c02cf73d0e2bfa18b321731dd35212eb6c92265 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:36 +0100 Subject: af_unix: handle idmapped mounts When binding a non-abstract AF_UNIX socket it will gain a representation in the filesystem. Enable the socket infrastructure to handle idmapped mounts by passing down the user namespace of the mount the socket will be created from. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-18-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Reviewed-by: James Morris Signed-off-by: Christian Brauner --- net/unix/af_unix.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 9a1f3c04402e..5a31307ceb76 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -996,8 +996,8 @@ static int unix_mknod(const char *sun_path, umode_t mode, struct path *res) */ err = security_path_mknod(&path, dentry, mode, 0); if (!err) { - err = vfs_mknod(&init_user_ns, d_inode(path.dentry), dentry, - mode, 0); + err = vfs_mknod(mnt_user_ns(path.mnt), d_inode(path.dentry), + dentry, mode, 0); if (!err) { res->mnt = mntget(path.mnt); res->dentry = dget(dentry); -- cgit