Fix off-by-one in BN_rand

[openssl.git] / crypto / bn / bn_rand.c

diff --git a/crypto/bn/bn_rand.c b/crypto/bn/bn_rand.c
index 7ac71ec8ed06b9a7a9a076b611f4f3a27a46dec7..f9fb2e9e45e01b9438a1c0bc5c4fb82311fbe363 100644 (file)
--- a/crypto/bn/bn_rand.c
+++ b/crypto/bn/bn_rand.c
@@ -121,6 +121,11 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
     int ret = 0, bit, bytes, mask;
     time_t tim;
 
+    if (bits < 0 || (bits == 1 && top > 0)) {
+        BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);
+        return 0;
+    }
+
     if (bits == 0) {
         BN_zero(rnd);
         return 1;
@@ -157,7 +162,8 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
         unsigned char c;
 
         for (i = 0; i < bytes; i++) {
-            RAND_pseudo_bytes(&c, 1);
+            if (RAND_pseudo_bytes(&c, 1) < 0)
+                goto err;
             if (c >= 128 && i > 0)
                 buf[i] = buf[i - 1];
             else if (c < 42)
@@ -168,7 +174,7 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
     }
 #endif
 
-    if (top != -1) {
+    if (top >= 0) {
         if (top) {
             if (bit == 0) {
                 buf[0] = 1;