ref: 17f7f6be4e1a316c0f5f26ff70e047aece4de2bc
dir: /sys/src/cmd/upas/dkim/dkim.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <libsec.h> #include <auth.h> #include <authsrv.h> #include <pool.h> char *signhdr[] = { "from:", "to:", "subject:", "date:", "message-id:", nil }; char *keyspec; char *domain; char *selector = "dkim"; int trim(char *p) { char *e; for(e = p; *e != 0; e++) if(*e == '\r' || *e == '\n') break; *e = 0; return e - p; } int usehdr(char *ln, char **hs) { char **p; for(p = signhdr; *p; p++) if(cistrncmp(ln, *p, strlen(*p)) == 0){ if((*hs = realloc(*hs, strlen(*hs) + strlen(*p) + 1)) == nil) sysfatal("realloc: %r"); strcat(*hs, *p); return 1; } return 0; } void append(char **m, int *nm, int *sz, char *ln, int n) { while(*nm + n + 2 >= *sz){ *sz += *sz/2; *m = realloc(*m, *sz); } memcpy(*m + *nm, ln, n); memcpy(*m + *nm + n, "\r\n", 2); *nm += n+2; } int sign(uchar *hash, int nhash, char **sig, int *nsig) { AuthRpc *rpc; int afd; if((afd = open("/mnt/factotum/rpc", ORDWR|OCEXEC)) < 0) return -1; if((rpc = auth_allocrpc(afd)) == nil){ close(afd); return -1; } if(auth_rpc(rpc, "start", keyspec, strlen(keyspec)) != ARok){ auth_freerpc(rpc); close(afd); return -1; } if(auth_rpc(rpc, "write", hash, nhash) != ARok) sysfatal("sign: write hash: %r"); if(auth_rpc(rpc, "read", nil, 0) != ARok) sysfatal("sign: read sig: %r"); if((*sig = malloc(rpc->narg)) == nil) sysfatal("malloc: %r"); *nsig = rpc->narg; memcpy(*sig, rpc->arg, *nsig); auth_freerpc(rpc); close(afd); return 0; } void usage(void) { fprint(2, "usage: %s [-s sel] -d dom\n", argv0); exits("usage"); } void main(int argc, char **argv) { int i, n, nhdr, nmsg, nsig, ntail, hdrsz, msgsz, use; uchar hdrhash[SHA2_256dlen], msghash[SHA2_256dlen]; char *hdr, *msg, *sig, *ln, *hdrset, *dhdr; Biobuf *rd, *wr; DigestState *sh, *sb; ARGBEGIN{ case 'd': domain = EARGF(usage()); break; case 's': selector = EARGF(usage()); break; default: usage(); break; }ARGEND; if(domain == nil) usage(); fmtinstall('H', encodefmt); fmtinstall('[', encodefmt); keyspec = smprint("proto=rsa service=dkim role=sign hash=sha256 domain=%s", domain); rd = Bfdopen(0, OREAD); wr = Bfdopen(1, OWRITE); nhdr = 0; hdrsz = 32; if((hdr = malloc(hdrsz)) == nil) sysfatal("malloc: %r"); nmsg = 0; msgsz = 32; if((msg = malloc(msgsz)) == nil) sysfatal("malloc: %r"); use = 0; sh = nil; hdrset = strdup(""); while((ln = Brdstr(rd, '\n', 1)) != nil){ n = trim(ln); if(n == 0 || (n == 1 && ln[0] == '\r' || ln[0] == '\n') || (n == 2 && strcmp(ln, "\r\n") == 0)) break; /* * strip out existing DKIM signatures, * for the sake of mailing lists and such. */ if(cistrcmp(ln, "DKIM-Signature:") == 0) continue; if(ln[0] != ' ' && ln[0] != '\t') use = usehdr(ln, &hdrset); if(use){ sh = sha2_256((uchar*)ln, n, nil, sh); sh = sha2_256((uchar*)"\r\n", 2, nil, sh); } append(&hdr, &nhdr, &hdrsz, ln, n); } sb = nil; ntail = 0; while((ln = Brdstr(rd, '\n', 0)) != nil){ n = trim(ln); if(n == 0){ ntail++; continue; } for(i = 0; i < ntail; i++){ sb = sha2_256((uchar*)"\r\n", 2, nil, sb); append(&msg, &nmsg, &msgsz, "", 0); ntail = 0; } sb = sha2_256((uchar*)ln, n, nil, sb); sb = sha2_256((uchar*)"\r\n", 2, nil, sb); append(&msg, &nmsg, &msgsz, ln, n); } if(nmsg == 0 || ntail > 1) sb = sha2_256((uchar*)"\r\n", 2, nil, sb); Bterm(rd); sha2_256(nil, 0, msghash, sb); dhdr = smprint( "DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=%s;\r\n" " h=%s; s=%s;\r\n" " bh=%.*[; \r\n" " b=", domain, hdrset, selector, (int)sizeof(msghash), msghash); if(dhdr == nil) sysfatal("smprint: %r"); sh = sha2_256((uchar*)dhdr, strlen(dhdr), nil, sh); sha2_256(nil, 0, hdrhash, sh); if(sign(hdrhash, sizeof(hdrhash), &sig, &nsig) == -1) sysfatal("sign: %r"); Bwrite(wr, dhdr, strlen(dhdr)); Bprint(wr, "%.*[\r\n", nsig, sig); Bwrite(wr, hdr, nhdr); Bprint(wr, "\n"); Bwrite(wr, msg, nmsg); Bterm(wr); free(hdr); free(msg); free(sig); exits(nil); }