Avoid cast between incompatible function types.

(cherry picked from commit 71f68cc45a269b206fc996309ef026f39d5af3df)

diff --git a/ChangeLog b/ChangeLog
index 2774c670dcfad5a17f0ea5a457949eca5c867199..78ebd75a2b6a6e57333f18ac721328c3810c45a7 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,11 @@
 2018-08-09  Niels Möller  <nisse@lysator.liu.se>
 
        Backported from master branch.
+       * nettle-internal.c (des_set_key_wrapper, des3_set_key_wrapper)
+       (blowfish128_set_key_wrapper): Wrapper functions, to avoid cast
+       between incompatible function types (which gcc-8 warns about).
+       Wrappers are expected to compile to a single jmp instruction.
+
        * des-compat.c (des_compat_des3_encrypt)
        (des_compat_des3_decrypt): Change length argument type to size_t.
 

diff --git a/nettle-internal.c b/nettle-internal.c
index 45f6f98e8fcc16d6c0a805509e742cc02e19c3ae..2a809472636878e89a81333faeba461ccdb590be 100644 (file)
--- a/nettle-internal.c
+++ b/nettle-internal.c
@@ -46,14 +46,32 @@
 #include "chacha.h"
 #include "salsa20.h"
 
-/* NOTE: A bit ugly. Ignores weak keys, and pretends the set_key
-   functions have no return value. */
+/* Wrapper functions discarding the return value. Needed for the
+   ciphers with weak keys. */
+static void
+des_set_key_wrapper (void *ctx, const uint8_t *key)
+{
+  des_set_key (ctx, key);
+}
+
+static void
+des3_set_key_wrapper (void *ctx, const uint8_t *key)
+{
+  des3_set_key (ctx, key);
+}
+
+static void
+blowfish128_set_key_wrapper (void *ctx, const uint8_t *key)
+{
+  blowfish128_set_key (ctx, key);
+}
+
 const struct nettle_cipher
 nettle_des = {
   "des", sizeof(struct des_ctx),
   DES_BLOCK_SIZE, DES_KEY_SIZE,
-  (nettle_set_key_func *) des_set_key,
-  (nettle_set_key_func *) des_set_key,
+  des_set_key_wrapper,
+  des_set_key_wrapper,
   (nettle_cipher_func *) des_encrypt,
   (nettle_cipher_func *) des_decrypt
 };
@@ -62,20 +80,18 @@ const struct nettle_cipher
 nettle_des3 = {
  "des3", sizeof(struct des3_ctx),
  DES3_BLOCK_SIZE, DES3_KEY_SIZE,
- (nettle_set_key_func *) des3_set_key,
- (nettle_set_key_func *) des3_set_key,
+ des3_set_key_wrapper,
+ des3_set_key_wrapper,
  (nettle_cipher_func *) des3_encrypt,
  (nettle_cipher_func *) des3_decrypt
 };
 
-/* NOTE: This is not as nice as one might think, as we pretend
-   blowfish_set_key has no return value. */
 const struct nettle_cipher
 nettle_blowfish128 =
   { "blowfish128", sizeof(struct blowfish_ctx),
     BLOWFISH_BLOCK_SIZE, BLOWFISH128_KEY_SIZE,
-    (nettle_set_key_func *) blowfish128_set_key,
-    (nettle_set_key_func *) blowfish128_set_key,
+    blowfish128_set_key_wrapper,
+    blowfish128_set_key_wrapper,
     (nettle_cipher_func *) blowfish_encrypt,
     (nettle_cipher_func *) blowfish_decrypt
   };