virlog: determine the hostname on startup CVE-2018-6764

At later point it might not be possible or even safe to use getaddrinfo(). It
can in turn result in a load of NSS module.

Notably, on a LXC container startup we may find ourselves with the guest
filesystem already having replaced the host one. Loading a NSS module
from the guest tree would allow a malicous guest to escape the
confinement of its container environment because libvirt will not yet
have locked it down.
This commit is contained in:
Lubomir Rintel 2018-01-27 23:43:58 +01:00 committed by Daniel P. Berrangé
parent 818a29e0c7
commit 759b4d1b0f

View File

@ -64,6 +64,7 @@
VIR_LOG_INIT("util.log");
static regex_t *virLogRegex;
static char *virLogHostname;
#define VIR_LOG_DATE_REGEX "[0-9]{4}-[0-9]{2}-[0-9]{2}"
@ -271,6 +272,12 @@ virLogOnceInit(void)
VIR_FREE(virLogRegex);
}
/* We get and remember the hostname early, because at later time
* it might not be possible to load NSS modules via getaddrinfo()
* (e.g. at container startup the host filesystem will not be
* accessible anymore. */
virLogHostname = virGetHostnameQuiet();
virLogUnlock();
return 0;
}
@ -466,17 +473,14 @@ static int
virLogHostnameString(char **rawmsg,
char **msg)
{
char *hostname = virGetHostnameQuiet();
char *hoststr;
if (!hostname)
if (!virLogHostname)
return -1;
if (virAsprintfQuiet(&hoststr, "hostname: %s", hostname) < 0) {
VIR_FREE(hostname);
if (virAsprintfQuiet(&hoststr, "hostname: %s", virLogHostname) < 0) {
return -1;
}
VIR_FREE(hostname);
if (virLogFormatString(msg, 0, NULL, VIR_LOG_INFO, hoststr) < 0) {
VIR_FREE(hoststr);