crypto: dh - Don't permit 'p' to be 0

[mirror_ubuntu-artful-kernel.git] / crypto / dh_helper.c

diff --git a/crypto/dh_helper.c b/crypto/dh_helper.c
index 8ba8a3f826200c611e4e340df4502dab2b112c40..708ae20d2d3ccf84280d97e446d350420c828c35 100644 (file)
--- a/crypto/dh_helper.c
+++ b/crypto/dh_helper.c
@@ -90,6 +90,14 @@ int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params)
        params->p = (void *)(ptr + params->key_size);
        params->g = (void *)(ptr + params->key_size + params->p_size);
 
+       /*
+        * Don't permit 'p' to be 0.  It's not a prime number, and it's subject
+        * to corner cases such as 'mod 0' being undefined or
+        * crypto_kpp_maxsize() returning 0.
+        */
+       if (memchr_inv(params->p, 0, params->p_size) == NULL)
+               return -EINVAL;
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(crypto_dh_decode_key);