options.c: fix broken unary minus usage

In Visual Studio when unary minus is applied to unsigned,
result is still unsigned. This means that when we use result
as function formal parameter, we pass incorrect value.

Fix by introducing frame_remove_from_extra_frame(),
which makes code semantically more clear and eliminates
the need in negative value and cast.

Since GCC didn't complain (and users too :), it probably performed
cast to signed automatically.

Signed-off-by: Lev Stipakov <lev@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1539258702-15427-1-git-send-email-lstipakov@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17739.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit ed31cf2ab718d879615dea81e6a17d26537ab43a)

diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
index dba3aa584ae513b7d73e6bc5ed4b0ecb4ae734fb..59e5ac54ad5907f9f914d8bbf0469a975683701d 100644 (file)
--- a/src/openvpn/crypto.c
+++ b/src/openvpn/crypto.c
@@ -721,7 +721,7 @@ crypto_adjust_frame_parameters(struct frame *frame,
                                bool packet_id,
                                bool packet_id_long_form)
 {
-    size_t crypto_overhead = 0;
+    unsigned int crypto_overhead = 0;
 
     if (packet_id)
     {
@@ -749,10 +749,10 @@ crypto_adjust_frame_parameters(struct frame *frame,
     frame_add_to_extra_frame(frame, crypto_overhead);
 
     msg(D_MTU_DEBUG, "%s: Adjusting frame parameters for crypto by %u bytes",
-        __func__, (unsigned int) crypto_overhead);
+        __func__, crypto_overhead);
 }
 
-size_t
+unsigned int
 crypto_max_overhead(void)
 {
     return packet_id_size(true) + OPENVPN_MAX_IV_LENGTH

diff --git a/src/openvpn/crypto.h b/src/openvpn/crypto.h
index e42f697f6c3bd1b7dc1a933ad8b4545e9f17572b..185bfd32d72a6b8d9c47d71111d54565aaf695cc 100644 (file)
--- a/src/openvpn/crypto.h
+++ b/src/openvpn/crypto.h
@@ -426,7 +426,7 @@ void crypto_adjust_frame_parameters(struct frame *frame,
                                     bool packet_id_long_form);
 
 /** Return the worst-case OpenVPN crypto overhead (in bytes) */
-size_t crypto_max_overhead(void);
+unsigned int crypto_max_overhead(void);
 
 /* Minimum length of the nonce used by the PRNG */
 #define NONCE_SECRET_LEN_MIN 16

diff --git a/src/openvpn/mtu.h b/src/openvpn/mtu.h
index a82154af98012c5ecfb434e67fdd037687afd025..cfa8d2f7df0d5b109a6b7622a8c67015ec44dbb8 100644 (file)
--- a/src/openvpn/mtu.h
+++ b/src/openvpn/mtu.h
@@ -271,11 +271,17 @@ frame_add_to_link_mtu(struct frame *frame, const int increment)
 }
 
 static inline void
-frame_add_to_extra_frame(struct frame *frame, const int increment)
+frame_add_to_extra_frame(struct frame *frame, const unsigned int increment)
 {
     frame->extra_frame += increment;
 }
 
+static inline void
+frame_remove_from_extra_frame(struct frame *frame, const unsigned int decrement)
+{
+    frame->extra_frame -= decrement;
+}
+
 static inline void
 frame_add_to_extra_tun(struct frame *frame, const int increment)
 {

diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index f964210693e91b62e0ed3f91f68ca6de8164250c..0257a6b5137eb5afd133494f288932b74d2cdedd 100644 (file)
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -3500,7 +3500,7 @@ calc_options_string_link_mtu(const struct options *o, const struct frame *frame)
         struct key_type fake_kt;
         init_key_type(&fake_kt, o->ciphername, o->authname, o->keysize, true,
                       false);
-        frame_add_to_extra_frame(&fake_frame, -(crypto_max_overhead()));
+        frame_remove_from_extra_frame(&fake_frame, crypto_max_overhead());
         crypto_adjust_frame_parameters(&fake_frame, &fake_kt, o->use_iv,
                                        o->replay, cipher_kt_mode_ofb_cfb(fake_kt.cipher));
         frame_finalize(&fake_frame, o->ce.link_mtu_defined, o->ce.link_mtu,

diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index 7284f460b4a182b136afaf93ef2ea6ac45c65b29..26d581df002ecfc8492c0ea6352e15a2dde4dffd 100644 (file)
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -1994,7 +1994,7 @@ tls_session_update_crypto_params(struct tls_session *session,
     }
 
     /* Update frame parameters: undo worst-case overhead, add actual overhead */
-    frame_add_to_extra_frame(frame, -(crypto_max_overhead()));
+    frame_remove_from_extra_frame(frame, crypto_max_overhead());
     crypto_adjust_frame_parameters(frame, &session->opt->key_type,
                                    options->use_iv, options->replay, packet_id_long_form);
     frame_finalize(frame, options->ce.link_mtu_defined, options->ce.link_mtu,