clear session keys from memory; ok djm@

1 files changed, 8 insertions, 2 deletions

diff --git a/usr.bin/ssh/umac.c b/usr.bin/ssh/umac.c
index 6d07b6365b3..b2fca71436e 100644
--- a/usr.bin/ssh/umac.c
+++ b/usr.bin/ssh/umac.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: umac.c,v 1.11 2014/07/22 07:13:42 guenther Exp $ */
+/* $OpenBSD: umac.c,v 1.12 2017/05/31 08:09:45 markus Exp $ */
 /* -----------------------------------------------------------------------
  * 
  * umac.c -- C Implementation UMAC Message Authentication
@@ -197,6 +197,8 @@ static void kdf(void *buffer_ptr, aes_int_key key, UINT8 ndx, int nbytes)
         aes_encryption(in_buf, out_buf, key);
         memcpy(dst_buf,out_buf,nbytes);
     }
+    explicit_bzero(in_buf, sizeof(in_buf));
+    explicit_bzero(out_buf, sizeof(out_buf));
 }
 
 /* The final UHASH result is XOR'd with the output of a pseudorandom
@@ -221,6 +223,7 @@ static void pdf_init(pdf_ctx *pc, aes_int_key prf_key)
     /* Initialize pdf and cache */
     memset(pc->nonce, 0, sizeof(pc->nonce));
     aes_encryption(pc->nonce, pc->cache, pc->prf_key);
+    explicit_bzero(buf, sizeof(buf));
 }
 
 static void pdf_gen_xor(pdf_ctx *pc, const UINT8 nonce[8], UINT8 buf[8])
@@ -539,6 +542,7 @@ static void nh_transform(nh_ctx *hc, const UINT8 *buf, UINT32 nbytes)
 
 /* ---------------------------------------------------------------------- */
 
+#if (__LITTLE_ENDIAN__)
 static void endian_convert(void *buf, UWORD bpw, UINT32 num_bytes)
 /* We endian convert the keys on little-endian computers to               */
 /* compensate for the lack of big-endian memory reads during hashing.     */
@@ -561,7 +565,6 @@ static void endian_convert(void *buf, UWORD bpw, UINT32 num_bytes)
         } while (--iters);
     }
 }
-#if (__LITTLE_ENDIAN__)
 #define endian_convert_if_le(x,y,z) endian_convert((x),(y),(z))
 #else
 #define endian_convert_if_le(x,y,z) do{}while(0)  /* Do nothing */
@@ -985,6 +988,7 @@ static void uhash_init(uhash_ctx_t ahc, aes_int_key prf_key)
     kdf(ahc->ip_trans, prf_key, 4, STREAMS * sizeof(UINT32));
     endian_convert_if_le(ahc->ip_trans, sizeof(UINT32),
                          STREAMS * sizeof(UINT32));
+    explicit_bzero(buf, sizeof(buf));
 }
 
 /* ---------------------------------------------------------------------- */
@@ -1194,6 +1198,7 @@ int umac_delete(struct umac_ctx *ctx)
     if (ctx) {
         if (ALLOC_BOUNDARY)
             ctx = (struct umac_ctx *)ctx->free_ptr;
+        explicit_bzero(ctx, sizeof(*ctx) + ALLOC_BOUNDARY);
         free(ctx);
     }
     return (1);
@@ -1221,6 +1226,7 @@ struct umac_ctx *umac_new(const u_char key[])
         aes_key_setup(key, prf_key);
         pdf_init(&ctx->pdf, prf_key);
         uhash_init(&ctx->hash, prf_key);
+        explicit_bzero(prf_key, sizeof(prf_key));
     }
         
     return (ctx);