Systemd-Journal: fix crash when the uid or gid do not have names (#16015)

1 files changed, 16 insertions, 14 deletions

diff --git a/collectors/systemd-journal.plugin/systemd-journal.c b/collectors/systemd-journal.plugin/systemd-journal.c
index 6efbb57550..522c127bde 100644
--- a/collectors/systemd-journal.plugin/systemd-journal.c
+++ b/collectors/systemd-journal.plugin/systemd-journal.c
@@ -511,23 +511,25 @@ static FACET_ROW_SEVERITY syslog_priority_to_facet_severity(int priority) {
 
 static char *uid_to_username(uid_t uid, char *buffer, size_t buffer_size) {
     static __thread char tmp[1024 + 1];
-    struct passwd pw, *result;
+    struct passwd pw, *result = NULL;
 
-    if (getpwuid_r(uid, &pw, tmp, 1024, &result) != 0 || result == NULL)
-        return NULL;
+    if (getpwuid_r(uid, &pw, tmp, sizeof(tmp), &result) != 0 || !result || !pw.pw_name || !(*pw.pw_name))
+        snprintfz(buffer, buffer_size - 1, "%u", uid);
+    else
+        snprintfz(buffer, buffer_size - 1, "%u (%s)", uid, pw.pw_name);
 
-    snprintfz(buffer, buffer_size - 1, "%u (%s)", uid, pw.pw_name);
     return buffer;
 }
 
 static char *gid_to_groupname(gid_t gid, char* buffer, size_t buffer_size) {
-    static __thread char tmp[1024 + 1];
-    struct group grp, *result;
+    static __thread char tmp[1024];
+    struct group grp, *result = NULL;
 
-    if (getgrgid_r(gid, &grp, tmp, 1024, &result) != 0 || result == NULL)
-        return NULL;
+    if (getgrgid_r(gid, &grp, tmp, sizeof(tmp), &result) != 0 || !result || !grp.gr_name || !(*grp.gr_name))
+        snprintfz(buffer, buffer_size - 1, "%u", gid);
+    else
+        snprintfz(buffer, buffer_size - 1, "%u (%s)", gid, grp.gr_name);
 
-    snprintfz(buffer, buffer_size - 1, "%u (%s)", gid, grp.gr_name);
     return buffer;
 }
 
@@ -560,7 +562,7 @@ static void netdata_systemd_journal_transform_priority(FACETS *facets __maybe_un
 // ----------------------------------------------------------------------------
 // UID and GID transformation
 
-#define UID_GID_HASHTABLE_SIZE 1000
+#define UID_GID_HASHTABLE_SIZE 10000
 
 struct word_t2str_hashtable_entry {
     struct word_t2str_hashtable_entry *next;
@@ -598,8 +600,8 @@ const char *uid_to_username_cached(uid_t uid, size_t *length) {
 
     struct word_t2str_hashtable_entry **e = word_t2str_hashtable_slot(&uid_hashtable, uid);
     if(!(*e)) {
-        static __thread char buf[1024 + 1];
-        const char *name = uid_to_username(uid, buf, 1024);
+        static __thread char buf[1024];
+        const char *name = uid_to_username(uid, buf, sizeof(buf));
         size_t size = strlen(name) + 1;
 
         *e = callocz(1, sizeof(struct word_t2str_hashtable_entry) + size);
@@ -619,8 +621,8 @@ const char *gid_to_groupname_cached(gid_t gid, size_t *length) {
 
     struct word_t2str_hashtable_entry **e = word_t2str_hashtable_slot(&gid_hashtable, gid);
     if(!(*e)) {
-        static __thread char buf[1024 + 1];
-        const char *name = gid_to_groupname(gid, buf, 1024);
+        static __thread char buf[1024];
+        const char *name = gid_to_groupname(gid, buf, sizeof(buf));
         size_t size = strlen(name) + 1;
 
         *e = callocz(1, sizeof(struct word_t2str_hashtable_entry) + size);