proc: add option to mount only a pids subset (6814ef2d) · Commits · 戴 / test

fs/proc/generic.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -269,6 +269,11 @@ 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 (fs_info->pidonly == PROC_PIDONLY_ON)
		return ERR_PTR(-ENOENT);

		return proc_lookup_de(dir, dentry, PDE(dir));
		}

		@@ -325,6 +330,10 @@ 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 (fs_info->pidonly == PROC_PIDONLY_ON)
		return 1;

		return proc_readdir_de(file, ctx, PDE(inode));
		}

fs/proc/inode.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -173,6 +173,8 @@ static int proc_show_options(struct seq_file seq, struct dentry root)
		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
		if (fs_info->hide_pid != HIDEPID_OFF)
		seq_printf(seq, ",hidepid=%u", fs_info->hide_pid);
		if (fs_info->pidonly != PROC_PIDONLY_OFF)
		seq_printf(seq, ",subset=pid");

		return 0;
		}
		@@ -463,6 +465,7 @@ 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 proc_ops, proc_open) open;
		@@ -476,6 +479,9 @@ static int proc_reg_open(struct inode inode, struct file file)
		return rv;
		}

		if (fs_info->pidonly == PROC_PIDONLY_ON)
		return -ENOENT;

		/*
		* Ensure that
		* 1) PDE's ->release hook will be called no matter what

fs/proc/root.c

+33 −0

Original line number	Diff line number	Diff line
		@@ -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_subset,
		};

		static const struct fs_parameter_spec proc_fs_parameters[] = {
		fsparam_u32("gid", Opt_gid),
		fsparam_u32("hidepid", Opt_hidepid),
		fsparam_string("subset", Opt_subset),
		{}
		};

		@@ -55,6 +58,29 @@ static inline int valid_hidepid(unsigned int value)
		value == HIDEPID_NOT_PTRACEABLE);
		}

		static int proc_parse_subset_param(struct fs_context fc, char value)
		{
		struct proc_fs_context *ctx = fc->fs_private;

		while (value) {
		char *ptr = strchr(value, ',');

		if (ptr != NULL)
		*ptr++ = '\0';

		if (*value != '\0') {
		if (!strcmp(value, "pid")) {
		ctx->pidonly = PROC_PIDONLY_ON;
		} else {
		return invalf(fc, "proc: unsupported subset option - %s\n", value);
		}
		}
		value = ptr;
		}

		return 0;
		}

		static int proc_parse_param(struct fs_context fc, struct fs_parameter param)
		{
		struct proc_fs_context *ctx = fc->fs_private;
		@@ -76,6 +102,11 @@ static int proc_parse_param(struct fs_context fc, struct fs_parameter param)
		ctx->hidepid = result.uint_32;
		break;

		case Opt_subset:
		if (proc_parse_subset_param(fc, param->string) < 0)
		return -EINVAL;
		break;

		default:
		return -EINVAL;
		}
		@@ -94,6 +125,8 @@ static void proc_apply_options(struct proc_fs_info *fs_info,
		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))
		fs_info->pidonly = ctx->pidonly;
		}

		static int proc_fill_super(struct super_block s, struct fs_context fc)

include/linux/proc_fs.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -50,12 +50,19 @@ enum {
		HIDEPID_NOT_PTRACEABLE = 4, /* Limit pids to only ptraceable pids */
		};

		/* definitions for proc mount option pidonly */
		enum {
		PROC_PIDONLY_OFF = 0,
		PROC_PIDONLY_ON = 1,
		};

		struct proc_fs_info {
		struct pid_namespace *pid_ns;
		struct dentry proc_self; / For /proc/self */
		struct dentry proc_thread_self; / For /proc/thread-self */
		kgid_t pid_gid;
		int hide_pid;
		int pidonly;
		};

		static inline struct proc_fs_info proc_sb_info(struct super_block sb)

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