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path: root/fs/init.c
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2021-01-24init: handle idmapped mountsChristian Brauner
Enable the init helpers to handle idmapped mounts by passing down the mount's user namespace. 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/20210121131959.646623-21-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24namei: prepare for idmapped mountsChristian Brauner
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 <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24namei: handle idmapped mounts in may_*() helpersChristian Brauner
The may_follow_link(), may_linkat(), may_lookup(), may_open(), may_o_create(), may_create_in_sticky(), may_delete(), and may_create() helpers determine whether the caller is privileged enough to perform the associated operations. Let them handle idmapped mounts by mapping the inode or fsids according to the mount's user namespace. Afterwards the checks are identical to non-idmapped inodes. The patch takes care to retrieve the mount's user namespace right before performing permission checks and passing it down into the fileystem so the user namespace can't change in between by someone idmapping a mount that is currently not idmapped. 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/20210121131959.646623-13-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24fs: add file and path permissions helpersChristian Brauner
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 <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-08-04init: add an init_dup helperChristoph Hellwig
Add a simple helper to grab a reference to a file and install it at the next available fd, and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-31init: add an init_utimes helperChristoph Hellwig
Add a simple helper to set timestamps with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_stat helperChristoph Hellwig
Add a simple helper to stat with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mknod helperChristoph Hellwig
Add a simple helper to mknod with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_mknod. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mkdir helperChristoph Hellwig
Add a simple helper to mkdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_mkdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_symlink helperChristoph Hellwig
Add a simple helper to symlink with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_symlink. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_link helperChristoph Hellwig
Add a simple helper to link with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_link. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_eaccess helperChristoph Hellwig
Add a simple helper to check if a file exists based on kernel space file name and switch the early init code over to it. Note that this theoretically changes behavior as it always is based on the effective permissions. But during early init that doesn't make a difference. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chmod helperChristoph Hellwig
Add a simple helper to chmod with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chown helperChristoph Hellwig
Add a simple helper to chown with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chroot helperChristoph Hellwig
Add a simple helper to chroot with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chroot. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chdir helperChristoph Hellwig
Add a simple helper to chdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_rmdir helperChristoph Hellwig
Add a simple helper to rmdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_rmdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_unlink helperChristoph Hellwig
Add a simple helper to unlink with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_unlink. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_umount helperChristoph Hellwig
Like ksys_umount, but takes a kernel pointer for the destination path. Switch over the umount in the init code, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mount helperChristoph Hellwig
Like do_mount, but takes a kernel pointer for the destination path. Switch over the mounts in the init code and devtmpfs to it, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig <hch@lst.de>