Commit 169d68ef authored by Al Viro's avatar Al Viro
Browse files

selinux: switch away from match_token() 



It's not a good fit, unfortunately, and the next step will make it
even less so.  Open-code what we need here.

Reviewed-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ba641862

security/selinux/hooks.c

+55 −27
Original line number Diff line number Diff line
@@ -459,19 +459,41 @@ enum { 
	Opt_defcontext = 3,

	Opt_rootcontext = 4,

	Opt_labelsupport = 5,

	Opt_nextmntopt = 6,

};



#define NUM_SEL_MNT_OPTS	(Opt_nextmntopt - 1)



static const match_table_t tokens = {

	{Opt_context, CONTEXT_STR "%s"},

	{Opt_fscontext, FSCONTEXT_STR "%s"},

	{Opt_defcontext, DEFCONTEXT_STR "%s"},

	{Opt_rootcontext, ROOTCONTEXT_STR "%s"},

	{Opt_labelsupport, LABELSUPP_STR},

	{Opt_error, NULL},

#define A(s, opt, has_arg) {s, sizeof(s) - 1, opt, has_arg}

static struct {

	const char *name;

	int len;

	int opt;

	bool has_arg;

} tokens[] = {

	A("context", Opt_context, true),

	A("fscontext", Opt_fscontext, true),

	A("defcontext", Opt_defcontext, true),

	A("rootcontext", Opt_rootcontext, true),

	A("seclabel", Opt_labelsupport, false),

};

#undef A



static int match_opt_prefix(char *s, int l, char **arg)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(tokens); i++) {

		size_t len = tokens[i].len;

		if (len > l || memcmp(s, tokens[i].name, len))

			continue;

		if (tokens[i].has_arg) {

			if (len == l || s[len] != '=')

				continue;

			*arg = s + len + 1;

		} else if (len != l)

			continue;

		return tokens[i].opt;

	}

	return Opt_error;

}



#define SEL_MOUNT_FAIL_MSG "SELinux:  duplicate or incompatible mount options\n"
@@ -988,6 +1010,9 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts) 
{

	struct selinux_mnt_opts *opts = *mnt_opts;



	if (token == Opt_labelsupport)	/* eaten and completely ignored */

		return 0;



	if (!opts) {

		opts = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);

		if (!opts)
@@ -1021,36 +1046,39 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts) 
	return 0;

Einval:

	pr_warn(SEL_MOUNT_FAIL_MSG);

	kfree(s);

	return -EINVAL;

}



static int selinux_parse_opts_str(char *options,

				  void **mnt_opts)

{

	char *p;

	char *p = options, *next;

	int rc;



	/* Standard string-based options. */

	while ((p = strsep(&options, "|")) != NULL) {

		int token, rc;

		substring_t args[MAX_OPT_ARGS];

		const char *arg;

	for (p = options; *p; p = next) {

		int token, len;

		char *arg = NULL;



		if (!*p)

			continue;



		token = match_token(p, tokens, args);

		next = strchr(p, '|');

		if (next) {

			len = next++ - p;

		} else {

			len = strlen(p);

			next = p + len;

		}



		if (token == Opt_labelsupport)	/* eaten and completely ignored */

		if (!len)

			continue;

		arg = match_strdup(&args[0]);



		token = match_opt_prefix(p, len, &arg);

		if (arg)

			arg = kmemdup_nul(arg, p + len - arg, GFP_KERNEL);

		rc = selinux_add_opt(token, arg, mnt_opts);

		if (unlikely(rc)) {

		if (rc) {

			kfree(arg);

			if (*mnt_opts) {

			selinux_free_mnt_opts(*mnt_opts);

			*mnt_opts = NULL;

			}

			return rc;

		}

	}