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

2 files changed, 6 insertions, 6 deletions

diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c
index 512885f9c8..946715ce5a 100644
--- a/src/udev/net/link-config.c
+++ b/src/udev/net/link-config.c
@@ -193,7 +193,7 @@ static int load_link(link_config_ctx *ctx, const char *filename) {
 
 static bool enable_name_policy(void) {
         _cleanup_free_ char *line = NULL;
-        char *w, *state;
+        const char *word, *state;
         int r;
         size_t l;
 
@@ -203,8 +203,8 @@ static bool enable_name_policy(void) {
         if (r <= 0)
                 return true;
 
-        FOREACH_WORD_QUOTED(w, l, line, state)
-                if (strneq(w, "net.ifnames=0", l))
+        FOREACH_WORD_QUOTED(word, l, line, state)
+                if (strneq(word, "net.ifnames=0", l))
                         return false;
 
         return true;
diff --git a/src/udev/udevd.c b/src/udev/udevd.c
index b75145eebf..f882cfb3ad 100644
--- a/src/udev/udevd.c
+++ b/src/udev/udevd.c
@@ -956,7 +956,7 @@ static int systemd_fds(struct udev *udev, int *rctrl, int *rnetlink) {
  */
 static void kernel_cmdline_options(struct udev *udev) {
         _cleanup_free_ char *line = NULL;
-        char *w, *state;
+        const char *word, *state;
         size_t l;
         int r;
 
@@ -966,10 +966,10 @@ static void kernel_cmdline_options(struct udev *udev) {
         if (r <= 0)
                 return;
 
-        FOREACH_WORD_QUOTED(w, l, line, state) {
+        FOREACH_WORD_QUOTED(word, l, line, state) {
                 char *s, *opt;
 
-                s = strndup(w, l);
+                s = strndup(word, l);
                 if (!s)
                         break;