Fix a missing NULL check in dsa_builtin_paramgen

We should check the last BN_CTX_get() call to ensure that it isn't NULL
before we try and use any of the allocated BIGNUMs.

Issue reported by Shi Lei.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 1ff7425d6130380bb00d3e64739633a4b21b11a3)

diff --git a/crypto/dsa/dsa_gen.c b/crypto/dsa/dsa_gen.c
index 3dac5500312afe1e321247685630a3533b58c66e..11f422e4b4bccbc2c9e90f74148d9f3dfae76e15 100644 (file)
--- a/crypto/dsa/dsa_gen.c
+++ b/crypto/dsa/dsa_gen.c
@@ -100,6 +100,9 @@ int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits,
     p = BN_CTX_get(ctx);
     test = BN_CTX_get(ctx);
 
+    if (test == NULL)
+        goto err;
+
     if (!BN_lshift(test, BN_value_one(), bits - 1))
         goto err;