From e9bef2f8146ccf152459248775eec8e8ce123865 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Wed, 22 Apr 2015 22:54:23 +0200

Subject: [PATCH] journalctl: rework code that checks whether we have access to

 /var/log/journal

- fix some memory leaks on error conditions

- handle all error cases properly, and log about failures

- move HAVE_ACL and no-HAVE_ACL code closer to each other

Cherry-picked from: e346512c684e9efae84c6442f7e6a5781564ecde

Related: #1318994

---

 src/journal/journalctl.c | 120 ++++++++++++++++++++-------------------

 src/shared/acl-util.c    | 102 ++++++++++++++++++---------------

 src/shared/acl-util.h    |   2 +-

 3 files changed, 119 insertions(+), 105 deletions(-)

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c

index 6ba8847798..f60e6415f8 100644

--- a/src/journal/journalctl.c

+++ b/src/journal/journalctl.c

@@ -1680,61 +1680,76 @@ static int verify(sd_journal *j) {

         return r;

 }

-#ifdef HAVE_ACL

 static int access_check_var_log_journal(sd_journal *j) {

+#ifdef HAVE_ACL

         _cleanup_strv_free_ char **g = NULL;

-        bool have_access;

+        const char* dir;

+#endif

         int r;

         assert(j);

-        have_access = in_group("systemd-journal") > 0;

+        if (arg_quiet)

+                return 0;

-        if (!have_access) {

-                const char* dir;

+        /* If we are root, we should have access, don't warn. */

+        if (getuid() == 0)

+                return 0;

-                if (access("/run/log/journal", F_OK) >= 0)

-                        dir = "/run/log/journal";

-                else

-                        dir = "/var/log/journal";

+        /* If we are in the 'systemd-journal' group, we should have

+         * access too. */

+        r = in_group("systemd-journal");

+        if (r < 0)

+                return log_error_errno(r, "Failed to check if we are in the 'systemd-journal' group: %m");

+        if (r > 0)

+                return 0;

-                /* 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, dir, &have_access);

-                if (r < 0)

-                        return r;

-        }

+#ifdef HAVE_ACL

+        if (laccess("/run/log/journal", F_OK) >= 0)

+                dir = "/run/log/journal";

+        else

+                dir = "/var/log/journal";

-        if (!have_access) {

+        /* If we are in any of the groups listed in the journal ACLs,

+         * then all is good, too. Let's enumerate all groups from the

+         * default ACL of the directory, which generally should allow

+         * access to most journal files too. */

+        r = acl_search_groups(dir, &g);

+        if (r < 0)

+                return log_error_errno(r, "Failed to search journal ACL: %m");

+        if (r > 0)

+                return 0;

-                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;

+        /* Print a pretty list, if there were ACLs set. */

+        if (!strv_isempty(g)) {

+                _cleanup_free_ char *s = NULL;

-                        r = strv_extend(&g, "systemd-journal");

-                        if (r < 0)

-                                return log_oom();

+                /* Thre are groups in the ACL, let's list them */

+                r = strv_extend(&g, "systemd-journal");

+                if (r < 0)

+                        return log_oom();

-                        strv_sort(g);

-                        strv_uniq(g);

+                strv_sort(g);

+                strv_uniq(g);

-                        s = strv_join(g, "', '");

-                        if (!s)

-                                return log_oom();

+                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 groups '%s' can see all messages.\n"

-                                   "      Pass -q to turn off this notice.", s);

-                }

+                log_notice("Hint: You are currently not seeing messages from other users and the system.\n"

+                           "      Users in groups '%s' can see all messages.\n"

+                           "      Pass -q to turn off this notice.", s);

+                return 1;

         }

+#endif

-        return 0;

+        /* If no ACLs were found, print a short version of the message. */

+        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.");

+

+        return 1;

 }

-#endif

 static int access_check(sd_journal *j) {

         Iterator it;

@@ -1746,30 +1761,15 @@ static int access_check(sd_journal *j) {

         if (set_isempty(j->errors)) {

                 if (ordered_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 /run/log/journal or /var/log/journal exist, 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

+                (void) access_check_var_log_journal(j);

-                if (ordered_hashmap_isempty(j->files)) {

-                        log_error("No journal files were opened due to insufficient permissions.");

-                        r = -EACCES;

-                }

+                if (ordered_hashmap_isempty(j->files))

+                        r = log_error_errno(EACCES, "No journal files were opened due to insufficient permissions.");

         }

         SET_FOREACH(code, j->errors, it) {

@@ -1778,8 +1778,12 @@ static int access_check(sd_journal *j) {

                 err = -PTR_TO_INT(code);

                 assert(err > 0);

-                if (err != EACCES)

-                        log_warning_errno(err, "Error was encountered while opening journal files: %m");

+                if (err == EACCES)

+                        continue;

+

+                log_warning_errno(err, "Error was encountered while opening journal files: %m");

+                if (r == 0)

+                        r = -err;

         }

         return r;

diff --git a/src/shared/acl-util.c b/src/shared/acl-util.c

index e67e9acb6a..d18a02f503 100644

--- a/src/shared/acl-util.c

+++ b/src/shared/acl-util.c

@@ -82,17 +82,18 @@ int calc_acl_mask_if_needed(acl_t *acl_p) {

                 if (tag == ACL_MASK)

                         return 0;

-                if (IN_SET(tag, ACL_USER, ACL_GROUP))

-                        goto calc;

+

+                if (IN_SET(tag, ACL_USER, ACL_GROUP)) {

+                        if (acl_calc_mask(acl_p) < 0)

+                                return -errno;

+

+                        return 1;

+                }

         }

         if (r < 0)

                 return -errno;

-        return 0;

-calc:

-        if (acl_calc_mask(acl_p) < 0)

-                return -errno;

-        return 1;

+        return 0;

 }

 int add_base_acls_if_needed(acl_t *acl_p, const char *path) {

@@ -159,59 +160,68 @@ int add_base_acls_if_needed(acl_t *acl_p, const char *path) {

         return 0;

 }

-int search_acl_groups(char*** dst, const char* path, bool* belong) {

-        acl_t acl;

+int acl_search_groups(const char *path, char ***ret_groups) {

+        _cleanup_strv_free_ char **g = NULL;

+        _cleanup_(acl_free) acl_t acl = NULL;

+        bool ret = false;

+        acl_entry_t entry;

+        int r;

         assert(path);

-        assert(belong);

         acl = acl_get_file(path, ACL_TYPE_DEFAULT);

-        if (acl) {

-                acl_entry_t entry;

-                int r;

-

-                r = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);

-                while (r > 0) {

-                        acl_tag_t tag;

-                        gid_t *gid;

-                        char *name;

+        if (!acl)

+                return -errno;

-                        r = acl_get_tag_type(entry, &tag;;

-                        if (r < 0)

-                                break;

+        r = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);

+        for (;;) {

+                _cleanup_(acl_free_gid_tpp) gid_t *gid = NULL;

+                acl_tag_t tag;

+

+                if (r < 0)

+                        return -errno;

+                if (r == 0)

+                        break;

+

+                if (acl_get_tag_type(entry, &tag) < 0)

+                        return -errno;

-                        if (tag != ACL_GROUP)

-                                goto next;

+                if (tag != ACL_GROUP)

+                        goto next;

-                        gid = acl_get_qualifier(entry);

-                        if (!gid)

-                                break;

+                gid = acl_get_qualifier(entry);

+                if (!gid)

+                        return -errno;

+

+                if (in_gid(*gid) > 0) {

+                        if (!ret_groups)

+                                return true;

-                        if (in_gid(*gid) > 0) {

-                                *belong = true;

-                                break;

-                        }

+                        ret = true;

+                }

+

+                if (ret_groups) {

+                        char *name;

                         name = gid_to_name(*gid);

-                        if (!name) {

-                                acl_free(acl);

-                                return log_oom();

-                        }

-

-                        r = strv_consume(dst, name);

-                        if (r < 0) {

-                                acl_free(acl);

-                                return log_oom();

-                        }

-

-                next:

-                        r = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);

+                        if (!name)

+                                return -ENOMEM;

+

+                        r = strv_consume(&g, name);

+                        if (r < 0)

+                                return r;

                 }

-                acl_free(acl);

+        next:

+                r = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);

         }

-        return 0;

+        if (ret_groups) {

+                *ret_groups = g;

+                g = NULL;

+        }

+

+        return ret;

 }

 int parse_acl(char *text, acl_t *acl_access, acl_t *acl_default, bool want_mask) {

diff --git a/src/shared/acl-util.h b/src/shared/acl-util.h

index fdb90063fa..c8bcc266d0 100644

--- a/src/shared/acl-util.h

+++ b/src/shared/acl-util.h

@@ -32,7 +32,7 @@

 int acl_find_uid(acl_t acl, uid_t uid, acl_entry_t *entry);

 int calc_acl_mask_if_needed(acl_t *acl_p);

 int add_base_acls_if_needed(acl_t *acl_p, const char *path);

-int search_acl_groups(char*** dst, const char* path, bool* belong);

+int acl_search_groups(const char* path, char ***ret_groups);

 int parse_acl(char *text, acl_t *acl_access, acl_t *acl_default, bool want_mask);

 int acls_for_file(const char *path, acl_type_t type, acl_t new, acl_t *acl);