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, 10 insertions, 12 deletions

diff --git a/src/libsystemd/sd-login/sd-login.c b/src/libsystemd/sd-login/sd-login.c
index 38ff944892..95cb6ff581 100644
--- a/src/libsystemd/sd-login/sd-login.c
+++ b/src/libsystemd/sd-login/sd-login.c
@@ -226,11 +226,10 @@ _public_ int sd_uid_get_display(uid_t uid, char **session) {
 }
 
 _public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat) {
-        char *w, *state;
         _cleanup_free_ char *t = NULL, *s = NULL, *p = NULL;
         size_t l;
         int r;
-        const char *variable;
+        const char *word, *variable, *state;
 
         assert_return(seat, -EINVAL);
 
@@ -251,8 +250,8 @@ _public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat)
         if (asprintf(&t, UID_FMT, uid) < 0)
                 return -ENOMEM;
 
-        FOREACH_WORD(w, l, s, state) {
-                if (strneq(t, w, l))
+        FOREACH_WORD(word, l, s, state) {
+                if (strneq(t, word, l))
                         return 1;
         }
 
@@ -587,10 +586,10 @@ _public_ int sd_seat_get_sessions(const char *seat, char ***sessions, uid_t **ui
         }
 
         if (uids && t) {
-                char *w, *state;
+                const char *word, *state;
                 size_t l;
 
-                FOREACH_WORD(w, l, t, state)
+                FOREACH_WORD(word, l, t, state)
                         n++;
 
                 if (n > 0) {
@@ -600,10 +599,10 @@ _public_ int sd_seat_get_sessions(const char *seat, char ***sessions, uid_t **ui
                         if (!b)
                                 return -ENOMEM;
 
-                        FOREACH_WORD(w, l, t, state) {
+                        FOREACH_WORD(word, l, t, state) {
                                 _cleanup_free_ char *k = NULL;
 
-                                k = strndup(w, l);
+                                k = strndup(word, l);
                                 if (!k)
                                         return -ENOMEM;
 
@@ -789,9 +788,8 @@ _public_ int sd_machine_get_class(const char *machine, char **class) {
 _public_ int sd_machine_get_ifindices(const char *machine, int **ifindices) {
         _cleanup_free_ char *netif = NULL;
         size_t l, allocated = 0, nr = 0;
-        char *w, *state;
         int *ni = NULL;
-        const char *p;
+        const char *p, *word, *state;
         int r;
 
         assert_return(machine_name_is_valid(machine), -EINVAL);
@@ -806,11 +804,11 @@ _public_ int sd_machine_get_ifindices(const char *machine, int **ifindices) {
                 return 0;
         }
 
-        FOREACH_WORD(w, l, netif, state) {
+        FOREACH_WORD(word, l, netif, state) {
                 char buf[l+1];
                 int ifi;
 
-                *(char*) (mempcpy(buf, w, l)) = 0;
+                *(char*) (mempcpy(buf, word, l)) = 0;
 
                 if (safe_atoi(buf, &ifi) < 0)
                         continue;