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authorAl Viro <viro@zeniv.linux.org.uk>2019-05-13 12:57:22 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2019-05-25 18:00:02 -0400
commitc3aabf0780a506225b53bfe2b5177dd5dfec093d (patch)
tree95e0457725a49ae8849f4e17014de6871b78cac3
parent059338aae33165179352a26b58d815801072c87d (diff)
downloadlinux-c3aabf0780a506225b53bfe2b5177dd5dfec093d.tar.bz2
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>
-rw-r--r--fs/fsopen.c2
-rw-r--r--fs/namespace.c2
-rw-r--r--fs/super.c6
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.
*/