sm-notify command: fix a use-after-free bug

The recv_reply() function was referencing host->ai in a freeaddrinfo(3)
call after it had freed @host.

This is not likely to be harmful in a single-threaded user context,
but it's still bad form, and it will get called out if testing
sm-notify with poisoned free memory.  The less noise, the better we
are able to see real problems.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
index d8e2c011701b05a539ba4c65ea83545541204542..d58e0be421859ed6c59880e917d53a53a874b877 100644 (file)
--- a/utils/statd/sm-notify.c
+++ b/utils/statd/sm-notify.c
@@ -131,6 +131,17 @@ static struct addrinfo *smn_lookup(const sa_family_t family, const char *name)
        return ai;
 }
 
+static void smn_forget_host(struct nsm_host *host)
+{
+       unlink(host->path);
+       free(host->path);
+       free(host->name);
+       if (host->ai)
+               freeaddrinfo(host->ai);
+
+       free(host);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -340,13 +351,8 @@ notify(void)
                        hp = hosts;
                        hosts = hp->next;
 
-                       if (notify_host(sock, hp)){
-                               unlink(hp->path);
-                               free(hp->name);
-                               free(hp->path);
-                               free(hp);
+                       if (notify_host(sock, hp))
                                continue;
-                       }
 
                        /* Set the timeout for this call, using an
                           exponential timeout strategy */
@@ -401,6 +407,7 @@ notify_host(int sock, struct nsm_host *host)
                        nsm_log(LOG_WARNING,
                                "%s doesn't seem to be a valid address,"
                                " skipped", host->name);
+                       smn_forget_host(host);
                        return 1;
                }
        }
@@ -545,11 +552,7 @@ recv_reply(int sock)
                if (p <= end) {
                        nsm_log(LOG_DEBUG, "Host %s notified successfully",
                                        hp->name);
-                       unlink(hp->path);
-                       free(hp->name);
-                       free(hp->path);
-                       free(hp);
-                       freeaddrinfo(hp->ai);
+                       smn_forget_host(hp);
                        return;
                }
        }