forked from lix-project/lix
Move preloadNSS() from initNix to initLibStore
It is required for the sandbox, which is a libstore responsibility; not just libmain. Part of an effort to make it easier to initialize the right things, by moving code into the appropriate libraries.
This commit is contained in:
parent
a58be39476
commit
e706ffa007
|
|
@ -10,7 +10,6 @@
|
|||
#include <cctype>
|
||||
#include <exception>
|
||||
#include <iostream>
|
||||
#include <mutex>
|
||||
|
||||
#include <cstdlib>
|
||||
#include <sys/time.h>
|
||||
|
|
@ -20,11 +19,6 @@
|
|||
#ifdef __linux__
|
||||
#include <features.h>
|
||||
#endif
|
||||
#ifdef __GLIBC__
|
||||
#include <gnu/lib-names.h>
|
||||
#include <nss.h>
|
||||
#include <dlfcn.h>
|
||||
#endif
|
||||
|
||||
#include <openssl/crypto.h>
|
||||
|
||||
|
|
@ -113,41 +107,6 @@ std::string getArg(const std::string & opt,
|
|||
return *i;
|
||||
}
|
||||
|
||||
static std::once_flag dns_resolve_flag;
|
||||
|
||||
static void preloadNSS() {
|
||||
/* builtin:fetchurl can trigger a DNS lookup, which with glibc can trigger a dynamic library load of
|
||||
one of the glibc NSS libraries in a sandboxed child, which will fail unless the library's already
|
||||
been loaded in the parent. So we force a lookup of an invalid domain to force the NSS machinery to
|
||||
load its lookup libraries in the parent before any child gets a chance to. */
|
||||
std::call_once(dns_resolve_flag, []() {
|
||||
#ifdef __GLIBC__
|
||||
/* On linux, glibc will run every lookup through the nss layer.
|
||||
* That means every lookup goes, by default, through nscd, which acts as a local
|
||||
* cache.
|
||||
* Because we run builds in a sandbox, we also remove access to nscd otherwise
|
||||
* lookups would leak into the sandbox.
|
||||
*
|
||||
* But now we have a new problem, we need to make sure the nss_dns backend that
|
||||
* does the dns lookups when nscd is not available is loaded or available.
|
||||
*
|
||||
* We can't make it available without leaking nix's environment, so instead we'll
|
||||
* load the backend, and configure nss so it does not try to run dns lookups
|
||||
* through nscd.
|
||||
*
|
||||
* This is technically only used for builtins:fetch* functions so we only care
|
||||
* about dns.
|
||||
*
|
||||
* All other platforms are unaffected.
|
||||
*/
|
||||
if (!dlopen(LIBNSS_DNS_SO, RTLD_NOW))
|
||||
warn("unable to load nss_dns backend");
|
||||
// FIXME: get hosts entry from nsswitch.conf.
|
||||
__nss_configure_lookup("hosts", "files dns");
|
||||
#endif
|
||||
});
|
||||
}
|
||||
|
||||
static void sigHandler(int signo) { }
|
||||
|
||||
|
||||
|
|
@ -218,7 +177,6 @@ void initNix()
|
|||
unsetenv("TMPDIR");
|
||||
#endif
|
||||
|
||||
preloadNSS();
|
||||
}
|
||||
|
||||
|
||||
|
|
|
|||
|
|
@ -7,6 +7,7 @@
|
|||
|
||||
#include <algorithm>
|
||||
#include <map>
|
||||
#include <mutex>
|
||||
#include <thread>
|
||||
#include <dlfcn.h>
|
||||
#include <sys/utsname.h>
|
||||
|
|
@ -15,6 +16,11 @@
|
|||
|
||||
#include <sodium/core.h>
|
||||
|
||||
#ifdef __GLIBC__
|
||||
#include <gnu/lib-names.h>
|
||||
#include <nss.h>
|
||||
#include <dlfcn.h>
|
||||
#endif
|
||||
|
||||
namespace nix {
|
||||
|
||||
|
|
@ -283,6 +289,42 @@ void initPlugins()
|
|||
settings.pluginFiles.pluginsLoaded = true;
|
||||
}
|
||||
|
||||
static void preloadNSS()
|
||||
{
|
||||
/* builtin:fetchurl can trigger a DNS lookup, which with glibc can trigger a dynamic library load of
|
||||
one of the glibc NSS libraries in a sandboxed child, which will fail unless the library's already
|
||||
been loaded in the parent. So we force a lookup of an invalid domain to force the NSS machinery to
|
||||
load its lookup libraries in the parent before any child gets a chance to. */
|
||||
static std::once_flag dns_resolve_flag;
|
||||
|
||||
std::call_once(dns_resolve_flag, []() {
|
||||
#ifdef __GLIBC__
|
||||
/* On linux, glibc will run every lookup through the nss layer.
|
||||
* That means every lookup goes, by default, through nscd, which acts as a local
|
||||
* cache.
|
||||
* Because we run builds in a sandbox, we also remove access to nscd otherwise
|
||||
* lookups would leak into the sandbox.
|
||||
*
|
||||
* But now we have a new problem, we need to make sure the nss_dns backend that
|
||||
* does the dns lookups when nscd is not available is loaded or available.
|
||||
*
|
||||
* We can't make it available without leaking nix's environment, so instead we'll
|
||||
* load the backend, and configure nss so it does not try to run dns lookups
|
||||
* through nscd.
|
||||
*
|
||||
* This is technically only used for builtins:fetch* functions so we only care
|
||||
* about dns.
|
||||
*
|
||||
* All other platforms are unaffected.
|
||||
*/
|
||||
if (!dlopen(LIBNSS_DNS_SO, RTLD_NOW))
|
||||
warn("unable to load nss_dns backend");
|
||||
// FIXME: get hosts entry from nsswitch.conf.
|
||||
__nss_configure_lookup("hosts", "files dns");
|
||||
#endif
|
||||
});
|
||||
}
|
||||
|
||||
static bool initLibStoreDone = false;
|
||||
|
||||
void assertLibStoreInitialized() {
|
||||
|
|
@ -299,6 +341,8 @@ void initLibStore() {
|
|||
|
||||
loadConfFile();
|
||||
|
||||
preloadNSS();
|
||||
|
||||
initLibStoreDone = true;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue