ref: f35d5ee5b036b7b4fa59b1839f52fca15b7f99f9
dir: /sys/src/cmd/auth/secstore/SConn.c/
#include <u.h> #include <libc.h> #include <mp.h> #include <libsec.h> #include "SConn.h" extern int verbose; typedef struct ConnState { uchar secret[SHA1dlen]; ulong seqno; RC4state rc4; } ConnState; typedef struct SS{ int fd; // file descriptor for read/write of encrypted data int alg; // if nonzero, "alg sha rc4_128" ConnState in, out; } SS; static int SC_secret(SConn *conn, uchar *sigma, int direction) { SS *ss = (SS*)(conn->chan); int nsigma = conn->secretlen; if(direction != 0){ hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->out.secret, nil); hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->in.secret, nil); }else{ hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->out.secret, nil); hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->in.secret, nil); } setupRC4state(&ss->in.rc4, ss->in.secret, 16); // restrict to 128 bits setupRC4state(&ss->out.rc4, ss->out.secret, 16); ss->alg = 1; return 0; } static void hash(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen]) { DigestState sha; uchar seq[4]; seq[0] = seqno>>24; seq[1] = seqno>>16; seq[2] = seqno>>8; seq[3] = seqno; memset(&sha, 0, sizeof sha); sha1(secret, SHA1dlen, nil, &sha); sha1(data, len, nil, &sha); sha1(seq, 4, d, &sha); } static int verify(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen]) { DigestState sha; uchar seq[4]; uchar digest[SHA1dlen]; seq[0] = seqno>>24; seq[1] = seqno>>16; seq[2] = seqno>>8; seq[3] = seqno; memset(&sha, 0, sizeof sha); sha1(secret, SHA1dlen, nil, &sha); sha1(data, len, nil, &sha); sha1(seq, 4, digest, &sha); return tsmemcmp(d, digest, SHA1dlen); } static int SC_read(SConn *conn, uchar *buf, int n) { SS *ss = (SS*)(conn->chan); uchar count[2], digest[SHA1dlen]; int len, nr; if(read(ss->fd, count, 2) != 2 || (count[0]&0x80) == 0){ snprint((char*)buf,n,"!SC_read invalid count"); return -1; } len = (count[0]&0x7f)<<8 | count[1]; // SSL-style count; no pad if(ss->alg){ len -= SHA1dlen; if(len <= 0 || readn(ss->fd, digest, SHA1dlen) != SHA1dlen){ snprint((char*)buf,n,"!SC_read missing sha1"); return -1; } if(len > n || readn(ss->fd, buf, len) != len){ snprint((char*)buf,n,"!SC_read missing data"); return -1; } rc4(&ss->in.rc4, digest, SHA1dlen); rc4(&ss->in.rc4, buf, len); if(verify(ss->in.secret, buf, len, ss->in.seqno, digest) != 0){ snprint((char*)buf,n,"!SC_read integrity check failed"); return -1; } }else{ if(len <= 0 || len > n){ snprint((char*)buf,n,"!SC_read implausible record length"); return -1; } if( (nr = readn(ss->fd, buf, len)) != len){ snprint((char*)buf,n,"!SC_read expected %d bytes, but got %d", len, nr); return -1; } } ss->in.seqno++; return len; } static int SC_write(SConn *conn, uchar *buf, int n) { SS *ss = (SS*)(conn->chan); uchar count[2], digest[SHA1dlen], enc[Maxmsg+1]; int len; if(n <= 0 || n > Maxmsg+1){ werrstr("!SC_write invalid n %d", n); return -1; } len = n; if(ss->alg) len += SHA1dlen; count[0] = 0x80 | len>>8; count[1] = len; if(write(ss->fd, count, 2) != 2){ werrstr("!SC_write invalid count"); return -1; } if(ss->alg){ hash(ss->out.secret, buf, n, ss->out.seqno, digest); rc4(&ss->out.rc4, digest, SHA1dlen); memcpy(enc, buf, n); rc4(&ss->out.rc4, enc, n); if(write(ss->fd, digest, SHA1dlen) != SHA1dlen || write(ss->fd, enc, n) != n){ werrstr("!SC_write error on send"); return -1; } }else{ if(write(ss->fd, buf, n) != n){ werrstr("!SC_write error on send"); return -1; } } ss->out.seqno++; return n; } static void SC_free(SConn *conn) { SS *ss = (SS*)(conn->chan); close(ss->fd); free(ss); free(conn); } SConn* newSConn(int fd) { SS *ss; SConn *conn; ss = (SS*)emalloc(sizeof(*ss)); conn = (SConn*)emalloc(sizeof(*conn)); ss->fd = fd; ss->alg = 0; conn->chan = (void*)ss; conn->secretlen = SHA1dlen; conn->free = SC_free; conn->secret = SC_secret; conn->read = SC_read; conn->write = SC_write; return conn; } void writerr(SConn *conn, char *s) { char buf[Maxmsg]; snprint(buf, Maxmsg, "!%s", s); conn->write(conn, (uchar*)buf, strlen(buf)); } int readstr(SConn *conn, char *s) { int n; n = conn->read(conn, (uchar*)s, Maxmsg); if(n >= 0){ s[n] = 0; if(s[0] == '!'){ memmove(s, s+1, n); n = -1; } }else{ strcpy(s, "connection read error"); } return n; }