Prepare for 2.6.0.0; delete s6-fillurandompool; add rngseed

Signed-off-by: Laurent Bercot <ska@appnovation.com>

1 files changed, 279 insertions, 0 deletions

diff --git a/src/minutils/rngseed.c b/src/minutils/rngseed.c
new file mode 100644
index 0000000..f00c4fc
--- /dev/null
+++ b/src/minutils/rngseed.c
@@ -0,0 +1,279 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#ifndef SKALIBS_HASCLOCKBOOT
+# error "CLOCK_BOOTTIME required"
+#endif
+
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/random.h>
+#include <linux/random.h>
+
+#include <skalibs/types.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/error.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/blake2s.h>
+#include <skalibs/random.h>
+
+#include <s6-linux-utils/config.h>
+
+#define USAGE "rngseed [ -d seeddir ] [ -v verbosity ] [ -r | -R ] [ -n | -N ] [ -w | -W ]"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+#define HASH_PREFIX "SeedRNG v1 Old+New Prefix"
+#define HASH_FALLBACK "SeedRNG v1 No New Seed Failure"
+
+struct flags_s
+{
+  unsigned int read: 1 ;
+  unsigned int rcred: 1 ;
+  unsigned int block: 1 ;
+  unsigned int write: 1 ;
+  unsigned int wcred: 1 ;
+} ;
+#define FLAGS_ZERO { .read = 0, .rcred = 1, .block = 1, .write = 0, .wcred = 1 }
+
+struct randpoolinfo_s
+{
+  int entropy_count ;
+  int buf_size ;
+  char buffer[512]  ;
+} ;
+
+static unsigned int verbosity = 1 ;
+
+static inline void mkdirp (char *s, size_t len)
+{
+  mode_t m = umask(0) ;
+  size_t i = 1 ;
+  for (; i < len ; i++) if (s[i] == '/')
+  {
+    s[i] = 0 ;
+    if (mkdir(s, 02755) < 0 && errno != EEXIST)
+      strerr_diefu2sys(111, "mkdir ", s) ;
+    s[i] = '/' ;
+  }
+  umask(m) ;
+}
+
+static inline int read_seed_nb (char *s, size_t len)
+{
+  int wcred ;
+  size_t w = 0 ;
+#ifdef SKALIBS_HASGETRANDOM
+  while (w < len)
+  {
+    ssize_t r = getrandom(s + w, len - w, GRND_NONBLOCK) ;
+    if (r == -1)
+    {
+      if (errno == EINTR) continue ;
+      if (error_isagain(errno)) break ;
+      strerr_diefu1sys(111, "getrandom") ;
+    }
+    else w += r ;
+  }
+  wcred = w >= len ;
+  if (!wcred)
+#else
+  tain dummy = TAIN_EPOCH ;
+  iopause_fd x = { .events = IOPAUSE_READ } ;
+  x.fd = openbc_read("/dev/random") ;
+  if (x.fd == -1) strerr_diefu2sys(111, "open ", "/dev/random") ;
+  wcred = iopause(&x, 1, &dummy, &dummy) ;
+  if (wcred == -1) strerr_diefu1sys(111, "iopause") ;
+  fd_close(x.fd) ;
+#endif
+  random_devurandom(s + w, len - w) ;
+  return wcred ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  blake2s_ctx ctx = BLAKE2S_INIT(32) ;
+  char const *seeddir = RNGSEED_DIR ;
+  struct flags_s flags = FLAGS_ZERO ;
+  PROG = "rngseed" ;
+  {
+    subgetopt l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "d:v:rRnNwW", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'd' : seeddir = l.arg ; break ;
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'r' : flags.read = 1 ; flags.rcred = 1 ; break ;
+        case 'R' : flags.read = 1 ; flags.rcred = 0 ; break ;
+        case 'n' : flags.block = 0 ; break ;
+        case 'N' : flags.block = 1 ; break ;
+        case 'w' : flags.write = 1 ; flags.wcred = 1 ; break ;
+        case 'W' : flags.write = 1 ; flags.wcred = 0 ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  {
+    size_t dirlen = strlen(seeddir) ;
+    char file[dirlen + 6] ;
+    memcpy(file, seeddir, dirlen) ;
+    while (dirlen && file[dirlen-1] == '/') dirlen-- ;
+    memcpy(file + dirlen, "/seed", 6) ;
+
+    if (flags.write)
+    {
+      struct timespec ts ;
+      if (dirlen)
+      {
+        file[dirlen] = 0 ;
+        mkdirp(file, dirlen) ;
+        if (mkdir(file, 0700) == -1)
+        {
+          struct stat st ;
+          if (errno != EEXIST) strerr_diefu2sys(111, "mkdir ", file) ;
+          if (stat(file, &st) == -1)
+            strerr_diefu2sys(111, "stat ", file) ;
+          if (st.st_mode & 0077)
+          {
+            if (verbosity)
+              strerr_warnw2sys(file, "has permissive modes, changing it to 0700") ;
+            if (chmod(file, 0700) == -1)
+              strerr_diefu2sys(111, "chmod ", file) ;
+          }
+        }
+        file[dirlen] = '/' ;
+      }
+      blake2s_update(&ctx, HASH_PREFIX, sizeof(HASH_PREFIX) - 1) ;
+      clock_gettime(CLOCK_REALTIME, &ts) ;
+      blake2s_update(&ctx, (char *)&ts, sizeof ts) ;
+      clock_gettime(CLOCK_BOOTTIME, &ts) ;
+      blake2s_update(&ctx, (char *)&ts, sizeof ts) ;
+    }
+
+    if (flags.read)
+    {
+      struct randpoolinfo_s req ;
+      struct stat st ;
+      size_t seedlen ;
+      int fd ;
+      if (verbosity >= 2) strerr_warni2x("reading seed from ", file) ;
+      fd = openbc_read(file) ;
+      if (fd == -1) strerr_diefu2sys(111, "open ", file) ;
+      errno = 0 ;
+      seedlen = allread(fd, req.buffer, 512) ;
+      if (errno) strerr_diefu2sys(111, "read from ", file) ;
+      if (!seedlen) strerr_dief2x(100, "empty ", file) ;
+      if (fstat(fd, &st) == -1) strerr_diefu2sys(111, "stat ", file) ;
+      if (unlink(file) == -1) strerr_diefu2sys(111, "unlink ", file) ;
+      fd_close(fd) ;
+      if (flags.write)
+      {
+        blake2s_update(&ctx, (char *)&seedlen, sizeof(seedlen)) ;
+        blake2s_update(&ctx, req.buffer, seedlen) ;
+      }
+      if (flags.rcred && st.st_mode & S_IWUSR && verbosity)
+        strerr_warnw2x(file, " was not marked as creditable") ;
+      req.entropy_count = flags.rcred && !(st.st_mode & S_IWUSR) ? (seedlen << 3) : 0 ;
+      req.buf_size = seedlen ;
+      fd = openbc_read("/dev/urandom") ;
+      if (fd == -1) strerr_diefu2sys(111, "open ", "/dev/urandom") ;
+      if (verbosity >= 2)
+      {
+        char fmt[SIZE_FMT] ;
+        fmt[size_fmt(fmt, seedlen << 3)] = 0 ;
+        strerr_warni4x("seeding with ", fmt, " bits", req.entropy_count ? "" : " without crediting") ;
+      }
+      if (ioctl(fd, RNDADDENTROPY, &req) == -1)
+        strerr_diefu1sys(111, "seed") ;
+      fd_close(fd) ;
+    }
+
+    if (flags.block)
+    {
+      if (verbosity >= 2)
+        strerr_warni1x("waiting for the entropy pool to initialize") ;
+#ifdef SKALIBS_HASGETRANDOM
+      char c ;
+      ssize_t r = getrandom(&c, 1, 0) ;
+      if (r == -1) strerr_diefu1sys(111, "getrandom") ;
+#else
+      iopause_fd x = { .events = IOPAUSE_READ } ;
+      x.fd = openbc_read("/dev/random") ;
+      if (x.fd == -1) strerr_diefu2sys(111, "open ", "/dev/random") ;
+      if (iopause(&x, 1, 0, 0) == -1) strerr_diefu1sys(111, "iopause") ;
+      fd_close(x.fd) ;
+#endif
+    }
+
+    if (flags.write)
+    {
+      char seed[512] ;
+      size_t len = 512 ;
+      int wcred = 1 ;
+      char s[SIZE_FMT] = "" ;
+      int fd = openbc_read("/proc/sys/kernel/random/poolsize") ;
+      if (fd < 0)
+      {
+        if (verbosity) strerr_warnwu2sys("open ", "/proc/sys/kernel/random/poolsize") ;
+      }
+      else
+      {
+        size_t r ;
+        errno = 0 ;
+        r = allread(fd, s, SIZE_FMT - 1) ;
+        if (errno)
+        {
+          if (verbosity) strerr_warnwu2sys("read from ", "/proc/sys/kernel/random/poolsize") ;
+        }
+        else
+        {
+          s[r] = 0 ;
+          if (!size_scan(s, &r))
+          {
+            if (verbosity) strerr_warnwu2sys("understand ", "/proc/sys/kernel/random/poolsize") ;
+          }
+          else len = (r + 7) >> 3 ;
+        }
+        fd_close(fd) ;
+      }
+      if (len < 32) len = 32 ;
+      if (len > 512) len = 512 ;
+
+      if (verbosity >= 2)
+      {
+        s[size_fmt(s, len << 3)] = 0 ;
+        strerr_warni3x("reading ", s, " bits of random to make the seed") ;
+      }
+      if (flags.block) random_buf(seed, len) ;
+      else wcred = read_seed_nb(seed, len) ;
+      if (!wcred && verbosity) strerr_warnwu1x("make the seed creditable") ;
+      blake2s_update(&ctx, (char *)&len, sizeof(len)) ;
+      blake2s_update(&ctx, seed, len) ;
+      blake2s_final(&ctx, seed + len - 32) ;
+      if (verbosity >= 2) strerr_warni2x("writing seed to ", file) ;
+      umask(0077) ;
+      if (!openwritenclose_unsafe_sync(file, seed, len))
+        strerr_diefu2sys(111, "write to ", file) ;
+      if (flags.wcred && wcred)
+      {
+        if (chmod(file, 0400) == -1 && verbosity)
+          strerr_warnwu3sys("mark ", file, "as creditable") ;
+      }
+    }
+  }
+
+  return 0 ;
+}