@@ -3949,18 +3949,23 @@ static bool mnt_already_visible(struct mnt_namespace *ns,
((mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK)))
continue;
- /* This mount is not fully visible if there are any
- * locked child mounts that cover anything except for
- * empty directories.
+ /* If this filesystem is completely dynamic, then it
+ * makes no sense to check for any child mounts.
*/
- list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
- struct inode *inode = child->mnt_mountpoint->d_inode;
- /* Only worry about locked mounts */
- if (!(child->mnt.mnt_flags & MNT_LOCKED))
- continue;
- /* Is the directory permanetly empty? */
- if (!is_empty_dir_inode(inode))
- goto next;
+ if (!(sb->s_iflags & SB_I_DYNAMIC)) {
+ /* This mount is not fully visible if there are any
+ * locked child mounts that cover anything except for
+ * empty directories.
+ */
+ list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
+ struct inode *inode = child->mnt_mountpoint->d_inode;
+ /* Only worry about locked mounts */
+ if (!(child->mnt.mnt_flags & MNT_LOCKED))
+ continue;
+ /* Is the directory permanetly empty? */
+ if (!is_empty_dir_inode(inode))
+ goto next;
+ }
}
/* Preserve the locked attributes */
*new_mnt_flags |= mnt_flags & (MNT_LOCK_READONLY | \
@@ -145,18 +145,21 @@ static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
return 0;
}
-static void proc_apply_options(struct proc_fs_info *fs_info,
+static void proc_apply_options(struct super_block *s,
struct fs_context *fc,
struct user_namespace *user_ns)
{
struct proc_fs_context *ctx = fc->fs_private;
+ struct proc_fs_info *fs_info = proc_sb_info(s);
if (ctx->mask & (1 << Opt_gid))
fs_info->pid_gid = make_kgid(user_ns, ctx->gid);
if (ctx->mask & (1 << Opt_hidepid))
fs_info->hide_pid = ctx->hidepid;
- if (ctx->mask & (1 << Opt_subset))
+ if (ctx->mask & (1 << Opt_subset)) {
fs_info->pidonly = ctx->pidonly;
+ s->s_iflags |= SB_I_DYNAMIC;
+ }
}
static int proc_fill_super(struct super_block *s, struct fs_context *fc)
@@ -170,9 +173,6 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc)
if (!fs_info)
return -ENOMEM;
- fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
- proc_apply_options(fs_info, fc, current_user_ns());
-
/* User space would break if executables or devices appear on proc */
s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
@@ -183,6 +183,9 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc)
s->s_time_gran = 1;
s->s_fs_info = fs_info;
+ fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
+ proc_apply_options(s, fc, current_user_ns());
+
/*
* procfs isn't actually a stacking filesystem; however, there is
* too much magic going on inside it to permit stacking things on
@@ -216,11 +219,10 @@ static int proc_fill_super(struct super_block *s, struct fs_context *fc)
static int proc_reconfigure(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
- struct proc_fs_info *fs_info = proc_sb_info(sb);
sync_filesystem(sb);
- proc_apply_options(fs_info, fc, current_user_ns());
+ proc_apply_options(sb, fc, current_user_ns());
return 0;
}
@@ -1413,6 +1413,7 @@ extern int send_sigurg(struct fown_struct *fown);
#define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */
#define SB_I_IMA_UNVERIFIABLE_SIGNATURE 0x00000020
#define SB_I_UNTRUSTED_MOUNTER 0x00000040
+#define SB_I_DYNAMIC 0x00000080
#define SB_I_SKIP_SYNC 0x00000100 /* Skip superblock at global sync */
Allow to mount of procfs with subset=pid option even if the entire procfs is not fully accessible to the user. Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> --- fs/namespace.c | 27 ++++++++++++++++----------- fs/proc/root.c | 16 +++++++++------- include/linux/fs.h | 1 + 3 files changed, 26 insertions(+), 18 deletions(-)