Fix off-by-one error.

Apart from writing 1 byte beyond an array allocated on the stack, this slipped
an unitialized byte in the seed used for key generation.

diff --git a/src/sptps.c b/src/sptps.c
index b907dad..3b9498c 100644 (file)
--- a/src/sptps.c
+++ b/src/sptps.c
@@ -209,7 +209,7 @@ static bool generate_key_material(sptps_t *s, const char *shared, size_t len) {
                memcpy(seed + 13, s->hiskex + 1, 32);
                memcpy(seed + 45, s->mykex + 1, 32);
        }
-       memcpy(seed + 78, s->label, s->labellen);
+       memcpy(seed + 77, s->label, s->labellen);
 
        // Use PRF to generate the key material
        if(!prf(shared, len, seed, s->labellen + 64 + 13, s->key, keylen))