selinux: rewrite selinux_sb_eat_lsm_opts()
make it use selinux_add_opt() and avoid separate copies - gather
non-LSM options by memmove() in place
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9b35007..5336d66 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2606,109 +2606,71 @@ static void selinux_sb_free_security(struct super_block *sb)
superblock_free_security(sb);
}
-static inline int match_prefix(char *prefix, int plen, char *option, int olen)
+static inline int opt_len(const char *s)
{
- if (plen > olen)
- return 0;
+ bool open_quote = false;
+ int len;
+ char c;
- return !memcmp(prefix, option, plen);
-}
-
-static inline int selinux_option(char *option, int len)
-{
- return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
- match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
- match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
- match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
- match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
-}
-
-static inline void take_option(char **to, char *from, int *first, int len)
-{
- if (!*first) {
- **to = ',';
- *to += 1;
- } else
- *first = 0;
- memcpy(*to, from, len);
- *to += len;
-}
-
-static inline void take_selinux_option(char **to, char *from, int *first,
- int len)
-{
- int current_size = 0;
-
- if (!*first) {
- **to = '|';
- *to += 1;
- } else
- *first = 0;
-
- while (current_size < len) {
- if (*from != '"') {
- **to = *from;
- *to += 1;
- }
- from += 1;
- current_size += 1;
- }
-}
-
-static int selinux_sb_copy_data(char *orig, char *copy)
-{
- int fnosec, fsec, rc = 0;
- char *in_save, *in_curr, *in_end;
- char *sec_curr, *nosec_save, *nosec;
- int open_quote = 0;
-
- in_curr = orig;
- sec_curr = copy;
-
- nosec = (char *)get_zeroed_page(GFP_KERNEL);
- if (!nosec) {
- rc = -ENOMEM;
- goto out;
- }
-
- nosec_save = nosec;
- fnosec = fsec = 1;
- in_save = in_end = orig;
-
- do {
- if (*in_end == '"')
+ for (len = 0; (c = s[len]) != '\0'; len++) {
+ if (c == '"')
open_quote = !open_quote;
- if ((*in_end == ',' && open_quote == 0) ||
- *in_end == '\0') {
- int len = in_end - in_curr;
-
- if (selinux_option(in_curr, len))
- take_selinux_option(&sec_curr, in_curr, &fsec, len);
- else
- take_option(&nosec, in_curr, &fnosec, len);
-
- in_curr = in_end + 1;
- }
- } while (*in_end++);
-
- strcpy(in_save, nosec_save);
- free_page((unsigned long)nosec_save);
-out:
- return rc;
+ if (c == ',' && !open_quote)
+ break;
+ }
+ return len;
}
static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
{
- char *s = (char *)get_zeroed_page(GFP_KERNEL);
- int err;
+ char *from = options;
+ char *to = options;
+ bool first = true;
- if (!s)
- return -ENOMEM;
- err = selinux_sb_copy_data(options, s);
- if (!err)
- err = selinux_parse_opts_str(s, mnt_opts);
- free_page((unsigned long)s);
- return err;
+ while (1) {
+ int len = opt_len(from);
+ int token, rc;
+ char *arg = NULL;
+
+ token = match_opt_prefix(from, len, &arg);
+
+ if (token != Opt_error) {
+ char *p, *q;
+
+ /* strip quotes */
+ if (arg) {
+ for (p = q = arg; p < from + len; p++) {
+ char c = *p;
+ if (c != '"')
+ *q++ = c;
+ }
+ arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
+ }
+ rc = selinux_add_opt(token, arg, mnt_opts);
+ if (unlikely(rc)) {
+ kfree(arg);
+ if (*mnt_opts) {
+ selinux_free_mnt_opts(*mnt_opts);
+ *mnt_opts = NULL;
+ }
+ return rc;
+ }
+ } else {
+ if (!first) { // copy with preceding comma
+ from--;
+ len++;
+ }
+ if (to != from)
+ memmove(to, from, len);
+ to += len;
+ first = false;
+ }
+ if (!from[len])
+ break;
+ from += len + 1;
+ }
+ *to = '\0';
+ return 0;
}
static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
