From 39e5e97e68a9c1bca3bcfa6c9316a83dad0b072d Mon Sep 17 00:00:00 2001

From: Franck Bui <fbui@suse.com>

Date: Thu, 29 Sep 2016 19:44:34 +0200

Subject: [PATCH] pid1: don't return any error in manager_dispatch_notify_fd()

 (#4240)

If manager_dispatch_notify_fd() fails and returns an error then the handling of

service notifications will be disabled entirely leading to a compromised system.

For example pid1 won't be able to receive the WATCHDOG messages anymore and

will kill all services supposed to send such messages.

(cherry picked from commit 9987750e7a4c62e0eb8473603150596ba7c3a015)

---

 src/core/manager.c | 13 +++++++++----

 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/core/manager.c b/src/core/manager.c

index a085ed899a..36488b673a 100644

--- a/src/core/manager.c

+++ b/src/core/manager.c

@@ -1643,10 +1643,14 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t

         n = recvmsg(m->notify_fd, &msghdr, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);

         if (n < 0) {

-                if (errno == EAGAIN || errno == EINTR)

-                        return 0;

+                if (!IN_SET(errno, EAGAIN, EINTR))

+                        log_error("Failed to receive notification message: %m");

-                return -errno;

+                /* It's not an option to return an error here since it

+                 * would disable the notification handler entirely. Services

+                 * wouldn't be able to send the WATCHDOG message for

+                 * example... */

+                return 0;

         }

         if (n == 0) {

                 log_debug("Got zero-length notification message. Ignoring.");

@@ -1673,7 +1677,8 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t

                 r = fdset_new_array(&fds, fd_array, n_fds);

                 if (r < 0) {

                         close_many(fd_array, n_fds);

-                        return log_oom();

+                        log_oom();

+                        return 0;

                 }

         }