Fix a problem with select and high fds.

* cipher/rndlinux.c (rndlinux_gather_random): Check fd before using
FD_SET.
--

If on systems where the maximum number of fds may be dynamically
configured to a value of FD_MAXSIZE or higher and the RNG is first
used after more than FD_SETSIZE-1 descriptors are in use, we disable
the progress messages from the RNG.  A better solution would be too
use poll but that requires more tests.

The same problem exists in rndunix.c - however this rng is only used
on old Unices and I assume that they don't feature dynamically
configured maximum fd sizes.

(from Libgcrypt commit 9487099071af4478d2882e633a0ade805801d6fa)

This may fix
GnuPG-bug-id: 1818

2 files changed, 22 insertions, 15 deletions

diff --git a/cipher/rndlinux.c b/cipher/rndlinux.c
index 9d40f47b8..709a7ad54 100644
--- a/cipher/rndlinux.c
+++ b/cipher/rndlinux.c
@@ -117,28 +117,33 @@ rndlinux_gather_random( void (*add)(const void*, size_t, int), int requester,
 #endif
 #endif
     while( length ) {
+#ifdef FD_SETSIZE
 	fd_set rfds;
 	struct timeval tv;
-	int rc;
+        int rc;
 
 	FD_ZERO(&rfds);
-	FD_SET(fd, &rfds);
 	tv.tv_sec = 3;
 	tv.tv_usec = 0;
-	if( !(rc=select(fd+1, &rfds, NULL, NULL, &tv)) ) {
-	    if( !warn )
+        if (fd < FD_SETSIZE)
+          {
+            FD_SET(fd, &rfds);
+            if( !(rc=select(fd+1, &rfds, NULL, NULL, &tv)) ) {
+              if( !warn )
 		tty_printf(
 _("\n"
 "Not enough random bytes available.  Please do some other work to give\n"
 "the OS a chance to collect more entropy! (Need %d more bytes)\n"), (int)length );
-	    warn = 1;
-	    continue;
-	}
-	else if( rc == -1 ) {
-	    tty_printf(
-		       "select() error: %s\n", strerror(errno));
-	    continue;
-	}
+              warn = 1;
+              continue;
+            }
+            else if( rc == -1 ) {
+              tty_printf(
+                         "select() error: %s\n", strerror(errno));
+              continue;
+            }
+          }
+#endif /*FD_SETSIZE*/
 
 	do {
 	    int nbytes = length < sizeof(buffer)? length : sizeof(buffer);
diff --git a/cipher/rndunix.c b/cipher/rndunix.c
index 75cf22ed0..72905e63b 100644
--- a/cipher/rndunix.c
+++ b/cipher/rndunix.c
@@ -290,10 +290,10 @@ static struct RI {
     /* This is a complex and screwball program.  Some systems have things
      * like rX_dmn, x = integer, for RAID systems, but the statistics are
      * pretty dodgy */
-#ifdef __QNXNTO__                                                             
+#ifdef __QNXNTO__
     { "/bin/pidin", "-F%A%B%c%d%E%I%J%K%m%M%n%N%p%P%S%s%T", SC(0.3),
              NULL, 0, 0, 0, 0       },
-#endif     
+#endif
 #if 0
     /* The following aren't enabled since they're somewhat slow and not very
      * unpredictable, however they give an indication of the sort of sources
@@ -625,6 +625,8 @@ slow_poll(FILE *dbgfp, int dbgall, size_t *nbytes )
 	FD_ZERO(&fds);
 	for (i = 0; dataSources[i].path != NULL; i++) {
 	    if (dataSources[i].pipe != NULL) {
+                /* FIXME: We need to make sure that PIPEFD is less
+                   than FD_SETSIZE.  */
 		FD_SET(dataSources[i].pipeFD, &fds);
 		moreSources = 1;
 	    }
@@ -707,7 +709,7 @@ start_gatherer( int pipefd )
 #else
 	nmax = 20; /* assume a reasonable value */
 #endif
-	{  
+	{
 	  int fd;
 	  if ((fd = open ("/dev/null", O_RDWR)) != -1) {
 	    dup2 (fd, STDIN_FILENO);