[v6,09/10] proc: add option to mount only a pids subset
diff mbox series

Message ID 20191225125151.1950142-10-gladkov.alexey@gmail.com
State New
Headers show
Series
  • proc: modernize proc to support multiple private instances
Related show

Commit Message

Alexey Gladkov Dec. 25, 2019, 12:51 p.m. UTC
This allows to hide all files and directories in the procfs that are not
related to tasks.

Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
---
 fs/proc/generic.c       | 20 ++++++++++++++++++++
 fs/proc/inode.c         |  8 ++++++++
 fs/proc/root.c          | 14 ++++++++++++++
 include/linux/proc_fs.h | 26 ++++++++++++++++++++++++++
 4 files changed, 68 insertions(+)

Comments

kernel test robot Dec. 25, 2019, 11:08 p.m. UTC | #1
Hi Alexey,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linux/master]
[cannot apply to lwn/docs-next linus/master v5.5-rc3 next-20191220]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Alexey-Gladkov/proc-modernize-proc-to-support-multiple-private-instances/20191226-060818
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 1522d9da40bdfe502c91163e6d769332897201fa
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.5.0-3) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/sunrpc/stats.h:13:0,
                    from include/linux/sunrpc/clnt.h:22,
                    from include/linux/nfs_fs.h:32,
                    from init/do_mounts.c:23:
   include/linux/proc_fs.h:162:47: warning: 'struct proc_info_fs' declared inside parameter list will not be visible outside of this definition or declaration
    static inline void proc_fs_set_pid_gid(struct proc_info_fs *fs_info, kgid_t gid)
                                                  ^~~~~~~~~~~~
   include/linux/proc_fs.h: In function 'proc_fs_pidonly':
>> include/linux/proc_fs.h:168:9: warning: 'return' with a value, in function returning void
     return PROC_PIDONLY_OFF;
            ^~~~~~~~~~~~~~~~
   include/linux/proc_fs.h:166:20: note: declared here
    static inline void proc_fs_pidonly(struct proc_fs_info *fs_info)
                       ^~~~~~~~~~~~~~~

vim +/return +168 include/linux/proc_fs.h

   161	
 > 162	static inline void proc_fs_set_pid_gid(struct proc_info_fs *fs_info, kgid_t gid)
   163	{
   164	}
   165	
   166	static inline void proc_fs_pidonly(struct proc_fs_info *fs_info)
   167	{
 > 168		return PROC_PIDONLY_OFF;
   169	}
   170	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation

Patch
diff mbox series

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 64e9ee1b129e..2fa919a5544d 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -267,6 +267,11 @@  struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
 		unsigned int flags)
 {
+	struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
+
+	if (proc_fs_pidonly(fs_info) == PROC_PIDONLY_ON)
+		return ERR_PTR(-ENOENT);
+
 	return proc_lookup_de(dir, dentry, PDE(dir));
 }
 
@@ -323,10 +328,24 @@  int proc_readdir_de(struct file *file, struct dir_context *ctx,
 int proc_readdir(struct file *file, struct dir_context *ctx)
 {
 	struct inode *inode = file_inode(file);
+	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
+
+	if (proc_fs_pidonly(fs_info) == PROC_PIDONLY_ON)
+		return 1;
 
 	return proc_readdir_de(file, ctx, PDE(inode));
 }
 
+static int proc_dir_open(struct inode *inode, struct file *file)
+{
+	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
+
+	if (proc_fs_pidonly(fs_info) == PROC_PIDONLY_ON)
+		return -ENOENT;
+
+	return 0;
+}
+
 /*
  * These are the generic /proc directory operations. They
  * use the in-memory "struct proc_dir_entry" tree to parse
@@ -336,6 +355,7 @@  static const struct file_operations proc_dir_operations = {
 	.llseek			= generic_file_llseek,
 	.read			= generic_read_dir,
 	.iterate_shared		= proc_readdir,
+	.open			= proc_dir_open,
 };
 
 /*
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 70b722fb8811..fe9d20da3862 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -107,6 +107,7 @@  static int proc_show_options(struct seq_file *seq, struct dentry *root)
 	struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
 	int hidepid = proc_fs_hide_pid(fs_info);
 	kgid_t gid = proc_fs_pid_gid(fs_info);
+	int pidonly = proc_fs_pidonly(fs_info);
 
 	if (!gid_eq(gid, GLOBAL_ROOT_GID))
 		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, gid));
@@ -114,6 +115,9 @@  static int proc_show_options(struct seq_file *seq, struct dentry *root)
 	if (hidepid != HIDEPID_OFF)
 		seq_printf(seq, ",hidepid=%u", hidepid);
 
+	if (pidonly != PROC_PIDONLY_OFF)
+		seq_printf(seq, ",pidonly=%u", pidonly);
+
 	return 0;
 }
 
@@ -333,12 +337,16 @@  proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
 
 static int proc_reg_open(struct inode *inode, struct file *file)
 {
+	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
 	struct proc_dir_entry *pde = PDE(inode);
 	int rv = 0;
 	typeof_member(struct file_operations, open) open;
 	typeof_member(struct file_operations, release) release;
 	struct pde_opener *pdeo;
 
+	if (proc_fs_pidonly(fs_info) == PROC_PIDONLY_ON)
+		return -ENOENT;
+
 	/*
 	 * Ensure that
 	 * 1) PDE's ->release hook will be called no matter what
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 3c7b29140293..fc26c22a5906 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -34,16 +34,19 @@  struct proc_fs_context {
 	unsigned int		mask;
 	int			hidepid;
 	int			gid;
+	int			pidonly;
 };
 
 enum proc_param {
 	Opt_gid,
 	Opt_hidepid,
+	Opt_pidonly,
 };
 
 static const struct fs_parameter_spec proc_param_specs[] = {
 	fsparam_u32("gid",	Opt_gid),
 	fsparam_u32("hidepid",	Opt_hidepid),
+	fsparam_u32("pidonly",	Opt_pidonly),
 	{}
 };
 
@@ -74,6 +77,13 @@  static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
 			return invalf(fc, "proc: hidepid value must be between 0 and 3.\n");
 		break;
 
+	case Opt_pidonly:
+		ctx->pidonly = result.uint_32;
+		if (ctx->pidonly < PROC_PIDONLY_OFF ||
+		    ctx->pidonly > PROC_PIDONLY_ON)
+			return invalf(fc, "proc: pidonly value must be 0 or 1.\n");
+		break;
+
 	default:
 		return -EINVAL;
 	}
@@ -94,6 +104,7 @@  static void proc_apply_options(struct proc_fs_info *fs_info,
 
 		proc_fs_set_pid_gid(fs_info, proc_fs_pid_gid(pidns_fs_info));
 		proc_fs_set_hide_pid(fs_info, proc_fs_hide_pid(pidns_fs_info));
+		proc_fs_set_pidonly(fs_info, proc_fs_pidonly(pidns_fs_info));
 	}
 
 	if (ctx->mask & (1 << Opt_gid))
@@ -101,6 +112,9 @@  static void proc_apply_options(struct proc_fs_info *fs_info,
 
 	if (ctx->mask & (1 << Opt_hidepid))
 		proc_fs_set_hide_pid(fs_info, ctx->hidepid);
+
+	if (ctx->mask & (1 << Opt_pidonly))
+		proc_fs_set_pidonly(fs_info, ctx->pidonly);
 }
 
 static int proc_fill_super(struct super_block *s, struct fs_context *fc)
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 83c87ea65505..ef1c0d9712b0 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -20,6 +20,12 @@  enum {
 	HIDEPID_NOT_PTRACABLE = 3, /* Limit pids to only ptracable pids */
 };
 
+/* definitions for proc mount option pidonly */
+enum {
+	PROC_PIDONLY_OFF = 0,
+	PROC_PIDONLY_ON  = 1,
+};
+
 struct proc_fs_info {
 	struct list_head pidns_entry;    /* Node in procfs_mounts of a pidns */
 	struct super_block *m_super;
@@ -28,6 +34,7 @@  struct proc_fs_info {
 	struct dentry *proc_thread_self; /* For /proc/thread-self */
 	kgid_t pid_gid;
 	int hide_pid;
+	int pidonly;
 };
 
 #ifdef CONFIG_PROC_FS
@@ -39,6 +46,11 @@  static inline struct proc_fs_info *proc_sb_info(struct super_block *sb)
 	return sb->s_fs_info;
 }
 
+static inline void proc_fs_set_pidonly(struct proc_fs_info *fs_info, int value)
+{
+	fs_info->pidonly = value;
+}
+
 static inline void proc_fs_set_hide_pid(struct proc_fs_info *fs_info, int hide_pid)
 {
 	fs_info->hide_pid = hide_pid;
@@ -49,6 +61,11 @@  static inline void proc_fs_set_pid_gid(struct proc_fs_info *fs_info, kgid_t gid)
 	fs_info->pid_gid = gid;
 }
 
+static inline int proc_fs_pidonly(struct proc_fs_info *fs_info)
+{
+	return fs_info->pidonly;
+}
+
 static inline int proc_fs_hide_pid(struct proc_fs_info *fs_info)
 {
 	return fs_info->hide_pid;
@@ -134,6 +151,10 @@  static inline struct proc_fs_info *proc_sb_info(struct super_block *sb)
 	return NULL;
 }
 
+static inline void proc_fs_set_pidonly(struct proc_fs_info *fs_info, int value)
+{
+}
+
 static inline void proc_fs_set_hide_pid(struct proc_fs_info *fs_info, int hide_pid)
 {
 }
@@ -142,6 +163,11 @@  static inline void proc_fs_set_pid_gid(struct proc_info_fs *fs_info, kgid_t gid)
 {
 }
 
+static inline void proc_fs_pidonly(struct proc_fs_info *fs_info)
+{
+	return PROC_PIDONLY_OFF;
+}
+
 static inline int proc_fs_hide_pid(struct proc_fs_info *fs_info)
 {
 	return 0;