Reject invalid quoted strings

String which ended in an unfinished quote were accepted, potentially
with bad memory accesses.

Reject anything which ends in a unfished quote, or contains
non-whitespace characters right after the closing quote.

_FOREACH_WORD now returns the invalid character in *state. But this return
value is not checked anywhere yet.

Also, make 'word' and 'state' variables const pointers, and rename 'w'
to 'word' in various places. Things are easier to read if the same name
is used consistently.

mbiebl_> am I correct that something like this doesn't work
mbiebl_> ExecStart=/usr/bin/encfs --extpass='/bin/systemd-ask-passwd "Unlock EncFS"'
mbiebl_> systemd seems to strip of the quotes
mbiebl_> systemctl status shows
mbiebl_> ExecStart=/usr/bin/encfs --extpass='/bin/systemd-ask-password Unlock EncFS  $RootDir $MountPoint
mbiebl_> which is pretty weird

1 files changed, 6 insertions, 7 deletions

diff --git a/src/core/main.c b/src/core/main.c
index 2741989c48..fad15c7c3f 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -455,9 +455,8 @@ static int config_parse_cpu_affinity2(
                 void *data,
                 void *userdata) {
 
-        char *w;
+        const char *word, *state;
         size_t l;
-        char *state;
         cpu_set_t *c = NULL;
         unsigned ncpus = 0;
 
@@ -465,12 +464,12 @@ static int config_parse_cpu_affinity2(
         assert(lvalue);
         assert(rvalue);
 
-        FOREACH_WORD_QUOTED(w, l, rvalue, state) {
+        FOREACH_WORD_QUOTED(word, l, rvalue, state) {
                 char *t;
                 int r;
                 unsigned cpu;
 
-                if (!(t = strndup(w, l)))
+                if (!(t = strndup(word, l)))
                         return log_oom();
 
                 r = safe_atou(t, &cpu);
@@ -559,7 +558,7 @@ static int config_parse_join_controllers(const char *unit,
                                          void *userdata) {
 
         unsigned n = 0;
-        char *state, *w;
+        const char *word, *state;
         size_t length;
 
         assert(filename);
@@ -568,10 +567,10 @@ static int config_parse_join_controllers(const char *unit,
 
         free_join_controllers();
 
-        FOREACH_WORD_QUOTED(w, length, rvalue, state) {
+        FOREACH_WORD_QUOTED(word, length, rvalue, state) {
                 char *s, **l;
 
-                s = strndup(w, length);
+                s = strndup(word, length);
                 if (!s)
                         return log_oom();