From 913ed91b7ac9e61d319a834d43de9f8bf2519f55 Mon Sep 17 00:00:00 2001 From: Franziskus Kiefer Date: Wed, 18 Jan 2017 11:30:03 +0100 Subject: Bug 1346735 - drop netstat from unix_rand; add new urandom only entropy source, r=mt,ttaubert Differential Revision: https://nss-review.dev.mozaws.net/D45 --- coreconf/config.gypi | 1 + lib/freebl/freebl_base.gypi | 5 ++ lib/freebl/sysrand.c | 4 +- lib/freebl/unix_rand.c | 171 -------------------------------------------- lib/freebl/unix_urandom.c | 50 +++++++++++++ 5 files changed, 59 insertions(+), 172 deletions(-) create mode 100644 lib/freebl/unix_urandom.c diff --git a/coreconf/config.gypi b/coreconf/config.gypi index f338dd2a0..6b15be0d7 100644 --- a/coreconf/config.gypi +++ b/coreconf/config.gypi @@ -108,6 +108,7 @@ 'ct_verif%': 0, 'nss_public_dist_dir%': '<(nss_dist_dir)/public', 'nss_private_dist_dir%': '<(nss_dist_dir)/private', + 'only_dev_random%': 1, }, 'target_defaults': { # Settings specific to targets should go here. diff --git a/lib/freebl/freebl_base.gypi b/lib/freebl/freebl_base.gypi index 7570eec88..d154e11e1 100644 --- a/lib/freebl/freebl_base.gypi +++ b/lib/freebl/freebl_base.gypi @@ -177,6 +177,11 @@ 'CT_VERIF', ], }], + [ 'only_dev_random==1', { + 'defines': [ + 'SEED_ONLY_DEV_URANDOM', + ] + }], [ 'OS=="mac"', { 'conditions': [ [ 'target_arch=="ia32"', { diff --git a/lib/freebl/sysrand.c b/lib/freebl/sysrand.c index 1b6cbdfcd..763f6af11 100644 --- a/lib/freebl/sysrand.c +++ b/lib/freebl/sysrand.c @@ -8,7 +8,9 @@ #include "seccomon.h" -#if defined(XP_UNIX) || defined(XP_BEOS) +#if (defined(XP_UNIX) || defined(XP_BEOS)) && defined(SEED_ONLY_DEV_URANDOM) +#include "unix_urandom.c" +#elif defined(XP_UNIX) || defined(XP_BEOS) #include "unix_rand.c" #endif #ifdef XP_WIN diff --git a/lib/freebl/unix_rand.c b/lib/freebl/unix_rand.c index 775e117ac..20c76ec66 100644 --- a/lib/freebl/unix_rand.c +++ b/lib/freebl/unix_rand.c @@ -682,134 +682,6 @@ RNG_GetNoise(void *buf, size_t maxbytes) return n; } -#define SAFE_POPEN_MAXARGS 10 /* must be at least 2 */ - -/* - * safe_popen is static to this module and we know what arguments it is - * called with. Note that this version only supports a single open child - * process at any time. - */ -static pid_t safe_popen_pid; -static struct sigaction oldact; - -static FILE * -safe_popen(char *cmd) -{ - int p[2], fd, argc; - pid_t pid; - char *argv[SAFE_POPEN_MAXARGS + 1]; - FILE *fp; - static char blank[] = " \t"; - static struct sigaction newact; - - if (pipe(p) < 0) - return 0; - - fp = fdopen(p[0], "r"); - if (fp == 0) { - close(p[0]); - close(p[1]); - return 0; - } - - /* Setup signals so that SIGCHLD is ignored as we want to do waitpid */ - newact.sa_handler = SIG_DFL; - newact.sa_flags = 0; - sigfillset(&newact.sa_mask); - sigaction(SIGCHLD, &newact, &oldact); - - pid = fork(); - switch (pid) { - int ndesc; - - case -1: - fclose(fp); /* this closes p[0], the fd associated with fp */ - close(p[1]); - sigaction(SIGCHLD, &oldact, NULL); - return 0; - - case 0: - /* dup write-side of pipe to stderr and stdout */ - if (p[1] != 1) - dup2(p[1], 1); - if (p[1] != 2) - dup2(p[1], 2); - - /* - * close the other file descriptors, except stdin which we - * try reassociating with /dev/null, first (bug 174993) - */ - if (!freopen("/dev/null", "r", stdin)) - close(0); - ndesc = getdtablesize(); - for (fd = PR_MIN(65536, ndesc); --fd > 2; close(fd)) - ; - - /* clean up environment in the child process */ - putenv("PATH=/bin:/usr/bin:/sbin:/usr/sbin:/etc:/usr/etc"); - putenv("SHELL=/bin/sh"); - putenv("IFS= \t"); - - /* - * The caller may have passed us a string that is in text - * space. It may be illegal to modify the string - */ - cmd = strdup(cmd); - /* format argv */ - argv[0] = strtok(cmd, blank); - argc = 1; - while ((argv[argc] = strtok(0, blank)) != 0) { - if (++argc == SAFE_POPEN_MAXARGS) { - argv[argc] = 0; - break; - } - } - - /* and away we go */ - execvp(argv[0], argv); - exit(127); - break; - - default: - close(p[1]); - break; - } - - /* non-zero means there's a cmd running */ - safe_popen_pid = pid; - return fp; -} - -static int -safe_pclose(FILE *fp) -{ - pid_t pid; - int status = -1, rv; - - if ((pid = safe_popen_pid) == 0) - return -1; - safe_popen_pid = 0; - - fclose(fp); - - /* yield the processor so the child gets some time to exit normally */ - PR_Sleep(PR_INTERVAL_NO_WAIT); - - /* if the child hasn't exited, kill it -- we're done with its output */ - while ((rv = waitpid(pid, &status, WNOHANG)) == -1 && errno == EINTR) - ; - if (rv == 0) { - kill(pid, SIGKILL); - while ((rv = waitpid(pid, &status, 0)) == -1 && errno == EINTR) - ; - } - - /* Reset SIGCHLD signal hander before returning */ - sigaction(SIGCHLD, &oldact, NULL); - - return status; -} - #ifdef DARWIN #include #if !TARGET_OS_IPHONE @@ -817,15 +689,9 @@ safe_pclose(FILE *fp) #endif #endif -/* Fork netstat to collect its output by default. Do not unset this unless - * another source of entropy is available - */ -#define DO_NETSTAT 1 - void RNG_SystemInfoForRNG(void) { - FILE *fp; char buf[BUFSIZ]; size_t bytes; const char *const *cp; @@ -860,12 +726,6 @@ RNG_SystemInfoForRNG(void) }; #endif -#if defined(BSDI) - static char netstat_ni_cmd[] = "netstat -nis"; -#else - static char netstat_ni_cmd[] = "netstat -ni"; -#endif - GiveSystemInfo(); bytes = RNG_GetNoise(buf, sizeof(buf)); @@ -890,7 +750,6 @@ RNG_SystemInfoForRNG(void) if (gethostname(buf, sizeof(buf)) == 0) { RNG_RandomUpdate(buf, strlen(buf)); } - GiveSystemInfo(); /* grab some data from system's PRNG before any other files. */ bytes = RNG_FileUpdate("/dev/urandom", SYSTEM_RNG_SEED_COUNT); @@ -914,33 +773,12 @@ RNG_SystemInfoForRNG(void) for (cp = files; *cp; cp++) RNG_FileForRNG(*cp); -/* - * Bug 100447: On BSD/OS 4.2 and 4.3, we have problem calling safe_popen - * in a pthreads environment. Therefore, we call safe_popen last and on - * BSD/OS we do not call safe_popen when we succeeded in getting data - * from /dev/urandom. - * - * Bug 174993: On platforms providing /dev/urandom, don't fork netstat - * either, if data has been gathered successfully. - */ - #if defined(BSDI) || defined(FREEBSD) || defined(NETBSD) || defined(OPENBSD) || defined(DARWIN) || defined(LINUX) || defined(HPUX) if (bytes) return; #endif #ifdef SOLARIS - -/* - * On Solaris, NSS may be initialized automatically from libldap in - * applications that are unaware of the use of NSS. safe_popen forks, and - * sometimes creates issues with some applications' pthread_atfork handlers. - * We always have /dev/urandom on Solaris 9 and above as an entropy source, - * and for Solaris 8 we have the libkstat interface, so we don't need to - * fork netstat. - */ - -#undef DO_NETSTAT if (!bytes) { /* On Solaris 8, /dev/urandom isn't available, so we use libkstat. */ PRUint32 kstat_bytes = 0; @@ -951,15 +789,6 @@ RNG_SystemInfoForRNG(void) PORT_Assert(bytes); } #endif - -#ifdef DO_NETSTAT - fp = safe_popen(netstat_ni_cmd); - if (fp != NULL) { - while ((bytes = fread(buf, 1, sizeof(buf), fp)) > 0) - RNG_RandomUpdate(buf, bytes); - safe_pclose(fp); - } -#endif } #define TOTAL_FILE_LIMIT 1000000 /* one million */ diff --git a/lib/freebl/unix_urandom.c b/lib/freebl/unix_urandom.c new file mode 100644 index 000000000..25e6ad91c --- /dev/null +++ b/lib/freebl/unix_urandom.c @@ -0,0 +1,50 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include +#include +#include "secerr.h" +#include "secrng.h" +#include "prprf.h" + +void +RNG_SystemInfoForRNG(void) +{ + PRUint8 bytes[SYSTEM_RNG_SEED_COUNT]; + size_t numBytes = RNG_SystemRNG(bytes, SYSTEM_RNG_SEED_COUNT); + if (!numBytes) { + /* error is set */ + return; + } + RNG_RandomUpdate(bytes, numBytes); +} + +size_t +RNG_SystemRNG(void *dest, size_t maxLen) +{ + int fd; + int bytes; + size_t fileBytes = 0; + unsigned char *buffer = dest; + + fd = open("/dev/urandom", O_RDONLY); + if (fd < 0) { + PORT_SetError(SEC_ERROR_NEED_RANDOM); + return 0; + } + while (fileBytes < maxLen) { + bytes = read(fd, buffer, maxLen - fileBytes); + if (bytes <= 0) { + break; + } + fileBytes += bytes; + buffer += bytes; + } + (void)close(fd); + if (fileBytes != maxLen) { + PORT_SetError(SEC_ERROR_NEED_RANDOM); + return 0; + } + return fileBytes; +} -- cgit v1.2.1