Fix from fips branch.

[openssl.git] / crypto / dsa / dsa_gen.c

diff --git a/crypto/dsa/dsa_gen.c b/crypto/dsa/dsa_gen.c
index aa0995564d126745dd0e798f0325403b67389660..2435fc8bc7c1c67b6d5acddf43251608f563df3c 100644 (file)
--- a/crypto/dsa/dsa_gen.c
+++ b/crypto/dsa/dsa_gen.c
@@ -120,8 +120,7 @@ int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
        BIGNUM *r0,*W,*X,*c,*test;
        BIGNUM *g=NULL,*q=NULL,*p=NULL;
        BN_MONT_CTX *mont=NULL;
-       size_t i;
-       int k,n=0,b,m=0, qsize = qbits >> 3;
+       int i, k,n=0,b,m=0, qsize = qbits >> 3;
        int counter=0;
        int r=0;
        BN_CTX *ctx=NULL;
@@ -141,13 +140,20 @@ int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
 
        bits = (bits+63)/64*64;
 
-       if (seed_len < qsize)
+       /* NB: seed_len == 0 is special case: copy generated seed to
+        * seed_in if it is not NULL.
+        */
+       if (seed_len && (seed_len < (size_t)qsize))
                seed_in = NULL;         /* seed buffer too small -- ignore */
-       if (seed_len > qsize) 
+       if (seed_len > (size_t)qsize) 
                seed_len = qsize;       /* App. 2.2 of FIPS PUB 186 allows larger SEED,
                                         * but our internal buffers are restricted to 160 bits*/
        if (seed_in != NULL)
+               {
                memcpy(seed, seed_in, seed_len);
+               /* set seed_in to NULL to avoid it being copied back */
+               seed_in = NULL;
+               }
 
        if ((ctx=BN_CTX_new()) == NULL)
                goto err;
@@ -329,7 +335,7 @@ err:
                        ok=0;
                        goto err;
                        }
-               if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed, qsize);
+               if (seed_in != NULL) memcpy(seed_in,seed, qsize);
                if (counter_ret != NULL) *counter_ret=counter;
                if (h_ret != NULL) *h_ret=h;
                }