- (dtucker) Wrap use of IPPROTO_IPV6 in an ifdef for platforms that don't

[openssh.git] / entropy.c

diff --git a/entropy.c b/entropy.c
index 9de292112b4329e3eca9df42d26447b5ea568856..8b705397ff9a1870b743583b69913808fc92b3b9 100644 (file)
--- a/entropy.c
+++ b/entropy.c
@@ -24,8 +24,24 @@
 
 #include "includes.h"
 
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+#include <stdarg.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+
 #include <openssl/rand.h>
 #include <openssl/crypto.h>
+#include <openssl/err.h>
 
 #include "ssh.h"
 #include "misc.h"
@@ -33,20 +49,19 @@
 #include "atomicio.h"
 #include "pathnames.h"
 #include "log.h"
+#include "buffer.h"
 
 /*
  * Portable OpenSSH PRNG seeding:
- * If OpenSSL has not "internally seeded" itself (e.g. pulled data from 
- * /dev/random), then we execute a "ssh-rand-helper" program which 
- * collects entropy and writes it to stdout. The child program must 
+ * If OpenSSL has not "internally seeded" itself (e.g. pulled data from
+ * /dev/random), then we execute a "ssh-rand-helper" program which
+ * collects entropy and writes it to stdout. The child program must
  * write at least RANDOM_SEED_SIZE bytes. The child is run with stderr
  * attached, so error/debugging output should be visible.
  *
  * XXX: we should tell the child how many bytes we need.
  */
 
-RCSID("$Id$");
-
 #ifndef OPENSSL_PRNG_ONLY
 #define RANDOM_SEED_SIZE 48
 static uid_t original_uid, original_euid;
@@ -61,19 +76,21 @@ seed_rng(void)
        pid_t pid;
        int ret;
        unsigned char buf[RANDOM_SEED_SIZE];
+       mysig_t old_sigchld;
 
        if (RAND_status() == 1) {
                debug3("RNG is ready, skipping seeding");
                return;
        }
 
-       debug3("Seeing PRNG from %s", SSH_RAND_HELPER);
+       debug3("Seeding PRNG from %s", SSH_RAND_HELPER);
 
        if ((devnull = open("/dev/null", O_RDWR)) == -1)
                fatal("Couldn't open /dev/null: %s", strerror(errno));
        if (pipe(p) == -1)
                fatal("pipe: %s", strerror(errno));
 
+       old_sigchld = signal(SIGCHLD, SIG_DFL);
        if ((pid = fork()) == -1)
                fatal("Couldn't fork: %s", strerror(errno));
        if (pid == 0) {
@@ -84,15 +101,16 @@ seed_rng(void)
                close(p[1]);
                close(devnull);
 
-               if (original_uid != original_euid && 
-                   setuid(original_uid) == -1) {
-                       fprintf(stderr, "(rand child) setuid: %s\n", 
-                           strerror(errno));
+               if (original_uid != original_euid &&
+                   ( seteuid(getuid()) == -1 ||
+                     setuid(original_uid) == -1) ) {
+                       fprintf(stderr, "(rand child) setuid(%li): %s\n",
+                           (long int)original_uid, strerror(errno));
                        _exit(1);
                }
-               
+
                execl(SSH_RAND_HELPER, "ssh-rand-helper", NULL);
-               fprintf(stderr, "(rand child) Couldn't exec '%s': %s\n", 
+               fprintf(stderr, "(rand child) Couldn't exec '%s': %s\n",
                    SSH_RAND_HELPER, strerror(errno));
                _exit(1);
        }
@@ -111,11 +129,12 @@ seed_rng(void)
        close(p[0]);
 
        if (waitpid(pid, &ret, 0) == -1)
-              fatal("Couldn't wait for ssh-rand-helper completion: %s", 
-                  strerror(errno));
+               fatal("Couldn't wait for ssh-rand-helper completion: %s",
+                   strerror(errno));
+       signal(SIGCHLD, old_sigchld);
 
        /* We don't mind if the child exits upon a SIGPIPE */
-       if (!WIFEXITED(ret) && 
+       if (!WIFEXITED(ret) &&
            (!WIFSIGNALED(ret) || WTERMSIG(ret) != SIGPIPE))
                fatal("ssh-rand-helper terminated abnormally");
        if (WEXITSTATUS(ret) != 0)
@@ -130,7 +149,7 @@ seed_rng(void)
 }
 
 void
-init_rng(void) 
+init_rng(void)
 {
        /*
         * OpenSSL version numbers: MNNFFPPS: major minor fix patch status
@@ -141,10 +160,35 @@ init_rng(void)
                    "have %lx", OPENSSL_VERSION_NUMBER, SSLeay());
 
 #ifndef OPENSSL_PRNG_ONLY
-       if ((original_uid = getuid()) == -1)
-               fatal("getuid: %s", strerror(errno));
-       if ((original_euid = geteuid()) == -1)
-               fatal("geteuid: %s", strerror(errno));
+       original_uid = getuid();
+       original_euid = geteuid();
 #endif
 }
 
+#ifndef OPENSSL_PRNG_ONLY
+void
+rexec_send_rng_seed(Buffer *m)
+{
+       u_char buf[RANDOM_SEED_SIZE];
+
+       if (RAND_bytes(buf, sizeof(buf)) <= 0) {
+               error("Couldn't obtain random bytes (error %ld)",
+                   ERR_get_error());
+               buffer_put_string(m, "", 0);
+       } else 
+               buffer_put_string(m, buf, sizeof(buf));
+}
+
+void
+rexec_recv_rng_seed(Buffer *m)
+{
+       u_char *buf;
+       u_int len;
+
+       buf = buffer_get_string_ret(m, &len);
+       if (buf != NULL) {
+               debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len);
+               RAND_add(buf, len, len);
+       }
+}
+#endif