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Commit d013db02 authored by Tyler Hicks's avatar Tyler Hicks Committed by Paul Moore
Browse files

seccomp: Separate read and write code for actions_logged sysctl 



Break the read and write paths of the kernel.seccomp.actions_logged
sysctl into separate functions to maintain readability. An upcoming
change will need to audit writes, but not reads, of this sysctl which
would introduce too many conditional code paths on whether or not the
'write' parameter evaluates to true.

Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 23bcc480

kernel/seccomp.c

+38 −22
Original line number Diff line number Diff line
@@ -1199,46 +1199,62 @@ static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names) 
	return true;

}



static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,

					  void __user *buffer, size_t *lenp,

					  loff_t *ppos)

static int read_actions_logged(struct ctl_table *ro_table, void __user *buffer,

			       size_t *lenp, loff_t *ppos)

{

	char names[sizeof(seccomp_actions_avail)];

	struct ctl_table table;

	int ret;



	if (write && !capable(CAP_SYS_ADMIN))

		return -EPERM;



	memset(names, 0, sizeof(names));



	if (!write) {

	if (!seccomp_names_from_actions_logged(names, sizeof(names),

					       seccomp_actions_logged))

		return -EINVAL;



	table = *ro_table;

	table.data = names;

	table.maxlen = sizeof(names);

	return proc_dostring(&table, 0, buffer, lenp, ppos);

}



static int write_actions_logged(struct ctl_table *ro_table, void __user *buffer,

				size_t *lenp, loff_t *ppos)

{

	char names[sizeof(seccomp_actions_avail)];

	struct ctl_table table;

	u32 actions_logged;

	int ret;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	memset(names, 0, sizeof(names));



	table = *ro_table;

	table.data = names;

	table.maxlen = sizeof(names);

	ret = proc_dostring(&table, write, buffer, lenp, ppos);

	ret = proc_dostring(&table, 1, buffer, lenp, ppos);

	if (ret)

		return ret;



	if (write) {

		u32 actions_logged;



		if (!seccomp_actions_logged_from_names(&actions_logged,

						       table.data))

	if (!seccomp_actions_logged_from_names(&actions_logged, table.data))

		return -EINVAL;



	if (actions_logged & SECCOMP_LOG_ALLOW)

		return -EINVAL;



	seccomp_actions_logged = actions_logged;

	return 0;

}



	return 0;

static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,

					  void __user *buffer, size_t *lenp,

					  loff_t *ppos)

{

	if (write)

		return write_actions_logged(ro_table, buffer, lenp, ppos);

	else

		return read_actions_logged(ro_table, buffer, lenp, ppos);

}



static struct ctl_path seccomp_sysctl_path[] = {