Add LCOV_EXCL* markers to crypto.c and crypto_s2k.c

This marks some lines as unreachable by the unit tests, and as
therefore excluded from test coverage.

(Note: This convention is only for lines that are absolutely
unreachable.  Don't use it anywhere you wouldn't add a
tor_fragile_assert().)

1 files changed, 4 insertions, 2 deletions

diff --git a/src/common/crypto_s2k.c b/src/common/crypto_s2k.c
index a9140c7553..149c39344c 100644
--- a/src/common/crypto_s2k.c
+++ b/src/common/crypto_s2k.c
@@ -57,7 +57,8 @@
 #define SCRYPT_KEY_LEN 32
 
 /** Given an algorithm ID (one of S2K_TYPE_*), return the length of the
- * specifier part of it, without the prefix type byte. */
+ * specifier part of it, without the prefix type byte.  Return -1 if it is not
+ * a valid algorithm ID. */
 static int
 secret_to_key_spec_len(uint8_t type)
 {
@@ -86,7 +87,8 @@ secret_to_key_key_len(uint8_t type)
     case S2K_TYPE_SCRYPT:
       return DIGEST256_LEN;
     default:
-      return -1;
+      tor_fragile_assert(); // LCOV_EXCL_LINE
+      return -1;            // LCOV_EXCL_LINE
   }
 }