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, 6 deletions

diff --git a/src/core/device.c b/src/core/device.c
index 444286e02b..2c41c7b6f4 100644
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -220,7 +220,7 @@ static int device_make_description(Unit *u, struct udev_device *dev, const char
 
 static int device_add_udev_wants(Unit *u, struct udev_device *dev) {
         const char *wants;
-        char *state, *w;
+        const char *word, *state;
         size_t l;
         int r;
 
@@ -234,11 +234,11 @@ static int device_add_udev_wants(Unit *u, struct udev_device *dev) {
         if (!wants)
                 return 0;
 
-        FOREACH_WORD_QUOTED(w, l, wants, state) {
+        FOREACH_WORD_QUOTED(word, l, wants, state) {
                 _cleanup_free_ char *n = NULL;
                 char e[l+1];
 
-                memcpy(e, w, l);
+                memcpy(e, word, l);
                 e[l] = 0;
 
                 n = unit_name_mangle(e, MANGLE_NOGLOB);
@@ -393,13 +393,13 @@ static int device_process_new_device(Manager *m, struct udev_device *dev) {
          * aliases */
         alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS");
         if (alias) {
-                char *state, *w;
+                const char *word, *state;
                 size_t l;
 
-                FOREACH_WORD_QUOTED(w, l, alias, state) {
+                FOREACH_WORD_QUOTED(word, l, alias, state) {
                         char e[l+1];
 
-                        memcpy(e, w, l);
+                        memcpy(e, word, l);
                         e[l] = 0;
 
                         if (path_is_absolute(e))