journalctl: various fixes to the access check logic

[elogind.git] / src / journal / journalctl.c

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 975c44fa9b76572cd32dc74434e5c1a38aeda73f..0a82a1cf15b899b781e9f5e4a490952d2af3bc09 100644 (file)
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -35,6 +35,11 @@
 #include <sys/ioctl.h>
 #include <linux/fs.h>
 
+#ifdef HAVE_ACL
+#include <sys/acl.h>
+#include "acl-util.h"
+#endif
+
 #include <systemd/sd-journal.h>
 
 #include "log.h"
@@ -596,7 +601,7 @@ static int add_this_boot(sd_journal *j) {
 }
 
 static int add_unit(sd_journal *j) {
-        _cleanup_free_ char *m = NULL, *u = NULL;
+        _cleanup_free_ char *u = NULL;
         int r;
 
         assert(j);
@@ -878,25 +883,114 @@ static int verify(sd_journal *j) {
         return r;
 }
 
-static int access_check(void) {
-
 #ifdef HAVE_ACL
-        if (access("/var/log/journal", F_OK) < 0 && geteuid() != 0 && in_group("systemd-journal") <= 0) {
-                log_error("Unprivileged users can't see messages unless persistent log storage is enabled. Users in the group 'systemd-journal' can always see messages.");
-                return -EACCES;
+static int access_check_var_log_journal(sd_journal *j) {
+        _cleanup_strv_free_ char **g = NULL;
+        bool have_access;
+        int r;
+
+        assert(j);
+
+        have_access = in_group("systemd-journal") > 0;
+
+        if (!have_access) {
+                /* Let's enumerate all groups from the default ACL of
+                 * the directory, which generally should allow access
+                 * to most journal files too */
+                r = search_acl_groups(&g, "/var/log/journal/", &have_access);
+                if (r < 0)
+                        return r;
         }
 
-        if (!arg_quiet && geteuid() != 0 && in_group("systemd-journal") <= 0)
-                log_warning("Showing user generated messages only. Users in the group 'systemd-journal' can see all messages. Pass -q to turn this notice off.");
-#else
-        if (geteuid() != 0 && in_group("systemd-journal") <= 0) {
-                log_error("No access to messages. Only users in the group 'systemd-journal' can see messages.");
-                return -EACCES;
+        if (!have_access) {
+
+                if (strv_isempty(g))
+                        log_notice("Hint: You are currently not seeing messages from other users and the system.\n"
+                                   "      Users in the 'systemd-journal' group can see all messages. Pass -q to\n"
+                                   "      turn off this notice.");
+                else {
+                        _cleanup_free_ char *s = NULL;
+
+                        r = strv_extend(&g, "systemd-journal");
+                        if (r < 0)
+                                return log_oom();
+
+                        strv_sort(g);
+                        strv_uniq(g);
+
+                        s = strv_join(g, "', '");
+                        if (!s)
+                                return log_oom();
+
+                        log_notice("Hint: You are currently not seeing messages from other users and the system.\n"
+                                   "      Users in the groups '%s' can see all messages.\n"
+                                   "      Pass -q to turn off this notice.", s);
+                }
         }
-#endif
 
         return 0;
 }
+#endif
+
+static int access_check(sd_journal *j) {
+        Iterator it;
+        void *code;
+        int r = 0;
+
+        assert(j);
+
+        if (set_isempty(j->errors)) {
+                if (hashmap_isempty(j->files))
+                        log_notice("No journal files were found.");
+                return 0;
+        }
+
+        if (set_contains(j->errors, INT_TO_PTR(-EACCES))) {
+#ifdef HAVE_ACL
+                /* If /var/log/journal doesn't even exist,
+                 * unprivileged users have no access at all */
+                if (access("/var/log/journal", F_OK) < 0 &&
+                    geteuid() != 0 &&
+                    in_group("systemd-journal") <= 0) {
+                        log_error("Unprivileged users cannot access messages, unless persistent log storage is\n"
+                                  "enabled. Users in the 'systemd-journal' group may always access messages.");
+                        return -EACCES;
+                }
+
+                /* If /var/log/journal exists, try to pring a nice
+                   notice if the user lacks access to it */
+                if (!arg_quiet && geteuid() != 0) {
+                        r = access_check_var_log_journal(j);
+                        if (r < 0)
+                                return r;
+                }
+#else
+                if (geteuid() != 0 && in_group("systemd-journal") <= 0) {
+                        log_error("Unprivileged users cannot access messages. Users in the 'systemd-journal' group\n"
+                                  "group may access messages.");
+                        return -EACCES;
+                }
+#endif
+
+                if (hashmap_isempty(j->files)) {
+                        log_error("No journal files were opened due to insufficient permissions.");
+                        r = -EACCES;
+                }
+        }
+
+        SET_FOREACH(code, j->errors, it) {
+                int err;
+
+                err = -PTR_TO_INT(code);
+                assert(err > 0);
+
+                if (err != EACCES)
+                        log_warning("Error was encountered while opening journal files: %s",
+                                    strerror(err));
+        }
+
+        return r;
+}
 
 int main(int argc, char *argv[]) {
         int r;
@@ -943,10 +1037,6 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        r = access_check();
-        if (r < 0)
-                return EXIT_FAILURE;
-
         if (arg_directory)
                 r = sd_journal_open_directory(&j, arg_directory, 0);
         else
@@ -956,6 +1046,10 @@ int main(int argc, char *argv[]) {
                 return EXIT_FAILURE;
         }
 
+        r = access_check(j);
+        if (r < 0)
+                return EXIT_FAILURE;
+
         if (arg_action == ACTION_VERIFY) {
                 r = verify(j);
                 goto finish;