core: be stricter when parsing User=/Group= fields

Let's verify the validity of the syntax of the user/group names set.

1 files changed, 118 insertions, 0 deletions

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 782e420e4c..d8aaf4ef40 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -64,6 +64,7 @@
 #include "unit-name.h"
 #include "unit-printf.h"
 #include "unit.h"
+#include "user-util.h"
 #include "utf8.h"
 #include "web-util.h"
 
@@ -1763,6 +1764,123 @@ int config_parse_sec_fix_0(
         return 0;
 }
 
+int config_parse_user_group(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        char **user = data, *n;
+        Unit *u = userdata;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(u);
+
+        if (isempty(rvalue))
+                n = NULL;
+        else {
+                _cleanup_free_ char *k = NULL;
+
+                r = unit_full_printf(u, rvalue, &k);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to resolve unit specifiers in %s, ignoring: %m", rvalue);
+                        return 0;
+                }
+
+                if (!valid_user_group_name_or_id(k)) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0, "Invalid user/group name or numeric ID, ignoring: %s", k);
+                        return 0;
+                }
+
+                n = k;
+                k = NULL;
+        }
+
+        free(*user);
+        *user = n;
+
+        return 0;
+}
+
+int config_parse_user_group_strv(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        char ***users = data;
+        Unit *u = userdata;
+        const char *p;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(u);
+
+        if (isempty(rvalue)) {
+                char **empty;
+
+                empty = new0(char*, 1);
+                if (!empty)
+                        return log_oom();
+
+                strv_free(*users);
+                *users = empty;
+
+                return 0;
+        }
+
+        p = rvalue;
+        for (;;) {
+                _cleanup_free_ char *word = NULL, *k = NULL;
+
+                r = extract_first_word(&p, &word, WHITESPACE, 0);
+                if (r == 0)
+                        break;
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Invalid syntax, ignoring: %s", rvalue);
+                        break;
+                }
+
+                r = unit_full_printf(u, word, &k);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to resolve unit specifiers in %s, ignoring: %m", word);
+                        continue;
+                }
+
+                if (!valid_user_group_name_or_id(k)) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0, "Invalid user/group name or numeric ID, ignoring: %s", k);
+                        continue;
+                }
+
+                r = strv_push(users, k);
+                if (r < 0)
+                        return log_oom();
+
+                k = NULL;
+        }
+
+        return 0;
+}
+
 int config_parse_busname_service(
                 const char *unit,
                 const char *filename,