Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d383d484 authored by Luis R. Rodriguez's avatar Luis R. Rodriguez Committed by Linus Torvalds
Browse files

sysctl: fold sysctl_writes_strict checks into helper 

The mode sysctl_writes_strict positional checks keep being copy and pasted
as we add new proc handlers.  Just add a helper to avoid code duplication.

Link: http://lkml.kernel.org/r/20170519033554.18592-4-mcgrof@kernel.org


Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@kernel.org>
Suggested-by: default avatarKees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a19ac337

kernel/sysctl.c

+32 −24
Original line number Diff line number Diff line
@@ -1970,6 +1970,32 @@ static void warn_sysctl_write(struct ctl_table *table) 
		current->comm, table->procname);

}



/**

 * proc_first_pos_non_zero_ignore - check if firs position is allowed

 * @ppos: file position

 * @table: the sysctl table

 *

 * Returns true if the first position is non-zero and the sysctl_writes_strict

 * mode indicates this is not allowed for numeric input types. String proc

 * hadlers can ignore the return value.

 */

static bool proc_first_pos_non_zero_ignore(loff_t *ppos,

					   struct ctl_table *table)

{

	if (!*ppos)

		return false;



	switch (sysctl_writes_strict) {

	case SYSCTL_WRITES_STRICT:

		return true;

	case SYSCTL_WRITES_WARN:

		warn_sysctl_write(table);

		return false;

	default:

		return false;

	}

}



/**

 * proc_dostring - read a string sysctl

 * @table: the sysctl table
@@ -1990,8 +2016,8 @@ static void warn_sysctl_write(struct ctl_table *table) 
int proc_dostring(struct ctl_table *table, int write,

		  void __user *buffer, size_t *lenp, loff_t *ppos)

{

	if (write && *ppos && sysctl_writes_strict == SYSCTL_WRITES_WARN)

		warn_sysctl_write(table);

	if (write)

		proc_first_pos_non_zero_ignore(ppos, table);



	return _proc_do_string((char *)(table->data), table->maxlen, write,

			       (char __user *)buffer, lenp, ppos);
@@ -2193,17 +2219,8 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, 
		conv = do_proc_dointvec_conv;



	if (write) {

		if (*ppos) {

			switch (sysctl_writes_strict) {

			case SYSCTL_WRITES_STRICT:

		if (proc_first_pos_non_zero_ignore(ppos, table))

			goto out;

			case SYSCTL_WRITES_WARN:

				warn_sysctl_write(table);

				break;

			default:

				break;

			}

		}



		if (left > PAGE_SIZE - 1)

			left = PAGE_SIZE - 1;
@@ -2468,17 +2485,8 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int 
	left = *lenp;



	if (write) {

		if (*ppos) {

			switch (sysctl_writes_strict) {

			case SYSCTL_WRITES_STRICT:

		if (proc_first_pos_non_zero_ignore(ppos, table))

			goto out;

			case SYSCTL_WRITES_WARN:

				warn_sysctl_write(table);

				break;

			default:

				break;

			}

		}



		if (left > PAGE_SIZE - 1)

			left = PAGE_SIZE - 1;