commit b8c3511d086c65fa4bc2ca7a128bb3a56ac95306
author Markus Armbruster <armbru@redhat.com> Tue May 14 20:03:06 2019 +0200
committer Markus Armbruster <armbru@redhat.com> Wed May 22 14:57:33 2019 +0200
tree 997af42ef7cfbd852cc6ca4e31350428b0d2a6e9
parent a4f667b6714916683408b983cfe0a615a725775f

qemu-bridge-helper: Fix misuse of isspace()

parse_acl_file() passes char values to isspace().  Undefined behavior
when the value is negative.  Not a security issue, because the
characters come from trusted $prefix/etc/qemu/bridge.conf and the
files it includes.

Furthermore, isspace()'s locale-dependence means qemu-bridge-helper
uses the user's locale for parsing $prefix/etc/bridge.conf.  Feels
wrong.

Use g_ascii_isspace() instead.  This fixes the undefined behavior, and
makes parsing of $prefix/etc/bridge.conf locale-independent.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190514180311.16028-2-armbru@redhat.com>

qemu-bridge-helper.c

diff --git a/qemu-bridge-helper.c b/qemu-bridge-helper.c
index 5396fbf..f9940de 100644
--- a/qemu-bridge-helper.c
+++ b/qemu-bridge-helper.c
@@ -75,7 +75,7 @@
         char *ptr = line;
         char *cmd, *arg, *argend;
 
-        while (isspace(*ptr)) {
+        while (g_ascii_isspace(*ptr)) {
             ptr++;
         }
 
@@ -99,12 +99,12 @@
 
         *arg = 0;
         arg++;
-        while (isspace(*arg)) {
+        while (g_ascii_isspace(*arg)) {
             arg++;
         }
 
         argend = arg + strlen(arg);
-        while (arg != argend && isspace(*(argend - 1))) {
+        while (arg != argend && g_ascii_isspace(*(argend - 1))) {
             argend--;
         }
         *argend = 0;