From 3c487e9d9b50e220f9eb32a020cbd9fd742d4405 Mon Sep 17 00:00:00 2001
From: Martin Kletzander <mkletzan@redhat.com>
Date: Tue, 27 Oct 2020 13:48:38 +0100
Subject: [PATCH 072/108] util: Avoid double free in virProcessSetAffinity

The cpu mask was free()'d immediately on any error and at the end of the
function, where it was expected that it would either error out and return or
goto another allocation if the code was to fail.  However since commit
9514e24984ee the error path did not return in one new case which caused
double-free in such situation.  In order to make the code more straightforward
just free the mask after it's been used even before checking the return code of
the call.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1819801

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
(cherry picked from commit 1f807631f402210d036ec4803e7adfefa222f786)
---
 src/util/virprocess.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/util/virprocess.c b/src/util/virprocess.c
index 141ebb54e0..c3f88d206b 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -450,6 +450,7 @@ int virProcessSetAffinity(pid_t pid, virBitmapPtr map)
     int numcpus = 1024;
     size_t masklen;
     cpu_set_t *mask;
+    int rv = -1;
 
     /* Not only may the statically allocated cpu_set_t be too small,
      * but there is no way to ask the kernel what size is large enough.
@@ -473,8 +474,10 @@ int virProcessSetAffinity(pid_t pid, virBitmapPtr map)
             CPU_SET_S(i, masklen, mask);
     }
 
-    if (sched_setaffinity(pid, masklen, mask) < 0) {
-        CPU_FREE(mask);
+    rv = sched_setaffinity(pid, masklen, mask);
+    CPU_FREE(mask);
+
+    if (rv < 0) {
         if (errno == EINVAL &&
             numcpus < (1024 << 8)) { /* 262144 cpus ought to be enough for anyone */
             numcpus = numcpus << 2;
@@ -484,7 +487,6 @@ int virProcessSetAffinity(pid_t pid, virBitmapPtr map)
                              _("cannot set CPU affinity on process %d"), pid);
         return -1;
     }
-    CPU_FREE(mask);
 
     return 0;
 }
-- 
2.33.0

