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| author | Al Viro <viro@zeniv.linux.org.uk> | 2019-05-13 12:57:22 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-05-25 18:00:02 -0400 |
| commit | c3aabf0780a506225b53bfe2b5177dd5dfec093d (patch) | |
| tree | 95e0457725a49ae8849f4e17014de6871b78cac3 /fs | |
| parent | 059338aae33165179352a26b58d815801072c87d (diff) | |
| download | lwn-c3aabf0780a506225b53bfe2b5177dd5dfec093d.tar.gz lwn-c3aabf0780a506225b53bfe2b5177dd5dfec093d.zip | |
move mount_capable() further out
Call graph of vfs_get_tree():
vfs_fsconfig_locked() # neither kernmount, nor submount
do_new_mount() # neither kernmount, nor submount
fc_mount()
afs_mntpt_do_automount() # submount
mount_one_hugetlbfs() # kernmount
pid_ns_prepare_proc() # kernmount
mq_create_mount() # kernmount
vfs_kern_mount()
simple_pin_fs() # kernmount
vfs_submount() # submount
kern_mount() # kernmount
init_mount_tree()
btrfs_mount()
nfs_do_root_mount()
The first two need the check (unconditionally).
init_mount_tree() is setting rootfs up; any capability
checks make zero sense for that one. And btrfs_mount()/
nfs_do_root_mount() have the checks already done in their
callers.
IOW, we can shift mount_capable() handling into
the two callers - one in the normal case of mount(2),
another - in fsconfig(2) handling of FSCONFIG_CMD_CREATE.
I.e. the syscalls that set a new filesystem up.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fsopen.c | 2 | ||||
| -rw-r--r-- | fs/namespace.c | 2 | ||||
| -rw-r--r-- | fs/super.c | 6 |
3 files changed, 4 insertions, 6 deletions
diff --git a/fs/fsopen.c b/fs/fsopen.c index c2891e933ef1..390172772f55 100644 --- a/fs/fsopen.c +++ b/fs/fsopen.c @@ -230,6 +230,8 @@ static int vfs_fsconfig_locked(struct fs_context *fc, int cmd, case FSCONFIG_CMD_CREATE: if (fc->phase != FS_CONTEXT_CREATE_PARAMS) return -EBUSY; + if (!mount_capable(fc)) + return -EPERM; fc->phase = FS_CONTEXT_CREATING; ret = vfs_get_tree(fc); if (ret) diff --git a/fs/namespace.c b/fs/namespace.c index ffb13f0562b0..1141641dff96 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2786,6 +2786,8 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags, err = vfs_parse_fs_string(fc, "source", name, strlen(name)); if (!err) err = parse_monolithic_mount_data(fc, data); + if (!err && !mount_capable(fc)) + err = -EPERM; if (!err) err = vfs_get_tree(fc); if (!err) diff --git a/fs/super.c b/fs/super.c index 2c38541cd89f..72b4a5afcfd6 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1415,12 +1415,6 @@ int vfs_get_tree(struct fs_context *fc) if (fc->root) return -EBUSY; - if (!(fc->sb_flags & SB_KERNMOUNT) && - fc->purpose != FS_CONTEXT_FOR_SUBMOUNT) { - if (!mount_capable(fc)) - return -EPERM; - } - /* Get the mountable root in fc->root, with a ref on the root and a ref * on the superblock. */ |