separate TLS code into a library, use in in wget

A new applet, ssl_client, is the TLS debug thing now.
It doubles as wget's NOMMU helper.
In MMU mode, wget still forks, but then directly calls TLS code,
without execing.

This can also be applied to sendmail/popmail (SMTPS / SMTP+starttls support)
and nc --ssl (ncat, nmap's nc clone, has such option).

function                                             old     new   delta
tls_handshake                                          -    1691   +1691
tls_run_copy_loop                                      -     443    +443
ssl_client_main                                        -     128    +128
packed_usage                                       30978   31007     +29
wget_main                                           2508    2535     +27
applet_names                                        2553    2560      +7
...
xwrite_encrypted                                     360     342     -18
tls_main                                            2127       -   -2127
------------------------------------------------------------------------------
(add/remove: 4/1 grow/shrink: 13/8 up/down: 2351/-2195)       Total: 156 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 67 insertions, 21 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 87f89c76d..ba3b1479e 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -355,6 +355,27 @@ extern char *skip_dev_pfx(const char *tty_name) FAST_FUNC;
 
 extern char *strrstr(const char *haystack, const char *needle) FAST_FUNC;
 
+/* dmalloc will redefine these to it's own implementation. It is safe
+ * to have the prototypes here unconditionally.  */
+void *malloc_or_warn(size_t size) FAST_FUNC RETURNS_MALLOC;
+void *xmalloc(size_t size) FAST_FUNC RETURNS_MALLOC;
+void *xzalloc(size_t size) FAST_FUNC RETURNS_MALLOC;
+void *xrealloc(void *old, size_t size) FAST_FUNC;
+/* After v = xrealloc_vector(v, SHIFT, idx) it's ok to use
+ * at least v[idx] and v[idx+1], for all idx values.
+ * SHIFT specifies how many new elements are added (1:2, 2:4, ..., 8:256...)
+ * when all elements are used up. New elements are zeroed out.
+ * xrealloc_vector(v, SHIFT, idx) *MUST* be called with consecutive IDXs -
+ * skipping an index is a bad bug - it may miss a realloc!
+ */
+#define xrealloc_vector(vector, shift, idx) \
+        xrealloc_vector_helper((vector), (sizeof((vector)[0]) << 8) + (shift), (idx))
+void* xrealloc_vector_helper(void *vector, unsigned sizeof_and_shift, int idx) FAST_FUNC;
+char *xstrdup(const char *s) FAST_FUNC RETURNS_MALLOC;
+char *xstrndup(const char *s, int n) FAST_FUNC RETURNS_MALLOC;
+void *xmemdup(const void *s, int n) FAST_FUNC RETURNS_MALLOC;
+
+
 //TODO: supply a pointer to char[11] buffer (avoid statics)?
 extern const char *bb_mode_string(mode_t mode) FAST_FUNC;
 extern int is_directory(const char *name, int followLinks) FAST_FUNC;
@@ -692,6 +713,52 @@ struct hostent *xgethostbyname(const char *name) FAST_FUNC;
 // Also mount.c and inetd.c are using gethostbyname(),
 // + inet_common.c has additional IPv4-only stuff
 
+#define SHA256_INSIZE  64
+#define SHA256_OUTSIZE 32
+#define AES_BLOCKSIZE  16
+#define AES128_KEYSIZE 16
+#define AES256_KEYSIZE 32
+struct tls_handshake_data; /* opaque */
+typedef struct tls_state {
+        int     ofd;
+        int     ifd;
+
+        int     min_encrypted_len_on_read;
+        uint8_t encrypt_on_write;
+
+        uint8_t *outbuf;
+        int     outbuf_size;
+
+        int     inbuf_size;
+        int     ofs_to_buffered;
+        int     buffered_size;
+        uint8_t *inbuf;
+
+        struct tls_handshake_data *hsd;
+
+        // RFC 5246
+        // sequence number
+        //   Each connection state contains a sequence number, which is
+        //   maintained separately for read and write states.  The sequence
+        //   number MUST be set to zero whenever a connection state is made the
+        //   active state.  Sequence numbers are of type uint64 and may not
+        //   exceed 2^64-1.
+        /*uint64_t read_seq64_be;*/
+        uint64_t write_seq64_be;
+
+        uint8_t client_write_MAC_key[SHA256_OUTSIZE];
+        uint8_t server_write_MAC_key[SHA256_OUTSIZE];
+        uint8_t client_write_key[AES256_KEYSIZE];
+        uint8_t server_write_key[AES256_KEYSIZE];
+} tls_state_t;
+
+static inline tls_state_t *new_tls_state(void)
+{
+        tls_state_t *tls = xzalloc(sizeof(*tls));
+        return tls;
+}
+void tls_handshake(tls_state_t *tls, const char *sni) FAST_FUNC;
+void tls_run_copy_loop(tls_state_t *tls) FAST_FUNC;
 
 void socket_want_pktinfo(int fd) FAST_FUNC;
 ssize_t send_to_from(int fd, void *buf, size_t len, int flags,
@@ -705,9 +772,6 @@ ssize_t recv_from_to(int fd, void *buf, size_t len, int flags,
 
 uint16_t inet_cksum(uint16_t *addr, int len) FAST_FUNC;
 
-char *xstrdup(const char *s) FAST_FUNC RETURNS_MALLOC;
-char *xstrndup(const char *s, int n) FAST_FUNC RETURNS_MALLOC;
-void *xmemdup(const void *s, int n) FAST_FUNC RETURNS_MALLOC;
 void overlapping_strcpy(char *dst, const char *src) FAST_FUNC;
 char *safe_strncpy(char *dst, const char *src, size_t size) FAST_FUNC;
 char *strncpy_IFNAMSIZ(char *dst, const char *src) FAST_FUNC;
@@ -753,24 +817,6 @@ enum {
 };
 void visible(unsigned ch, char *buf, int flags) FAST_FUNC;
 
-/* dmalloc will redefine these to it's own implementation. It is safe
- * to have the prototypes here unconditionally.  */
-void *malloc_or_warn(size_t size) FAST_FUNC RETURNS_MALLOC;
-void *xmalloc(size_t size) FAST_FUNC RETURNS_MALLOC;
-void *xzalloc(size_t size) FAST_FUNC RETURNS_MALLOC;
-void *xrealloc(void *old, size_t size) FAST_FUNC;
-/* After v = xrealloc_vector(v, SHIFT, idx) it's ok to use
- * at least v[idx] and v[idx+1], for all idx values.
- * SHIFT specifies how many new elements are added (1:2, 2:4, ..., 8:256...)
- * when all elements are used up. New elements are zeroed out.
- * xrealloc_vector(v, SHIFT, idx) *MUST* be called with consecutive IDXs -
- * skipping an index is a bad bug - it may miss a realloc!
- */
-#define xrealloc_vector(vector, shift, idx) \
-        xrealloc_vector_helper((vector), (sizeof((vector)[0]) << 8) + (shift), (idx))
-void* xrealloc_vector_helper(void *vector, unsigned sizeof_and_shift, int idx) FAST_FUNC;
-
-
 extern ssize_t safe_read(int fd, void *buf, size_t count) FAST_FUNC;
 extern ssize_t nonblock_immune_read(int fd, void *buf, size_t count) FAST_FUNC;
 // NB: will return short read on error, not -1,