confile: be stricter in config helpers

We never call these helper without an initialized config afaict but
since we're now exposing these two functions to oss-fuzz directly in a
way we never do to users so let's be stricter about it.

Inspired-by: #3733
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index 576e6f2d89cad6fd99939cc162ccd4db0d268c30..6220f47025b7adc6b076ff3ed4a8b6c012162467 100644 (file)
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -2878,6 +2878,9 @@ static int parse_line(char *buffer, void *data)
        char *dup = buffer;
        struct parse_line_conf *plc = data;
 
+       if (!plc->conf)
+               return syserror_set(-EINVAL, "Missing config");
+
        /* If there are newlines in the config file we should keep them. */
        empty_line = lxc_is_line_empty(dup);
        if (empty_line)
@@ -2947,6 +2950,9 @@ static struct new_config_item *parse_new_conf_line(char *buffer)
        char *dup = buffer;
        char *dot, *key, *line, *value;
 
+       if (is_empty_string(buffer))
+               return log_error_errno(NULL, EINVAL, "Empty configuration line");
+
        linep = line = strdup(dup);
        if (!line)
                return NULL;
@@ -2999,16 +3005,19 @@ static struct new_config_item *parse_new_conf_line(char *buffer)
 
 int lxc_config_read(const char *file, struct lxc_conf *conf, bool from_include)
 {
-       struct parse_line_conf c;
+       struct parse_line_conf plc;
+
+       if (!conf)
+               return syserror_set(-EINVAL, "Missing config");
 
-       c.conf = conf;
-       c.from_include = from_include;
+       plc.conf = conf;
+       plc.from_include = from_include;
 
        /* Catch only the top level config file name in the structure. */
        if (!conf->rcfile)
                conf->rcfile = strdup(file);
 
-       return lxc_file_for_each_line_mmap(file, parse_line, &c);
+       return lxc_file_for_each_line_mmap(file, parse_line, &plc);
 }
 
 int lxc_config_define_add(struct lxc_list *defines, char *arg)