From 89b7b67a13ebb7965cc7f13ad0595e2194a2d34c Mon Sep 17 00:00:00 2001 From: Jannis Hoffmann Date: Wed, 3 Jul 2024 15:48:04 +0200 Subject: add sqmail-4.2.29a --- src/qmail-dksign.c | 511 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 511 insertions(+) create mode 100644 src/qmail-dksign.c (limited to 'src/qmail-dksign.c') diff --git a/src/qmail-dksign.c b/src/qmail-dksign.c new file mode 100644 index 0000000..5135cd4 --- /dev/null +++ b/src/qmail-dksign.c @@ -0,0 +1,511 @@ +#include +#include +#include +#include +#include +#include +#include "sig.h" +#include "stralloc.h" +#include "buffer.h" +#include "error.h" +#include "auto_qmail.h" +#include "control.h" +#include "str.h" +#include "exit.h" +#include "case.h" +#include "constmap.h" +#include "uint_t.h" +#include "fd.h" +#include "logmsg.h" +#include "open.h" +#include "fmt.h" +#include "fmtqfn.h" +#include "readwrite.h" +#include "qmail.h" +#include "wait.h" +#include "pathexec.h" +#include "rcpthosts.h" + +#define WHO "qmail-dksign" + +#define DOMAINKEYS "ssl/domainkeys/" + +/** @file qmail-dksign.c -- generate signature and attach in DKIM header to outgoing message + + Steps: + ------ + a) DKIM controls: get private key for sending domain + b) Prepare two staging files at queue/dkim (before and after signing) + c) Read input at fd0 and insert CR for every line and store at dkim/x/pre + d) DKIM sign the message with provided private key and store at dkim/y/post + e) Copy signed file from fd to 0 + f) Invoke qmail-remote (respecting the \r\n) + g) Remove staging files (pre/post) + + Hack for hybrid signatures: + --------------------------- + + a) selector is a link to RSA private key + b) selector2 is a link to Ed25519 private key + c) Both are provided in the 'selector' field of dkimdomains separated by colon + d) The coupled selector information is provided to qmail-dkim as: -yselector ,-Yselector2 + e) The RSA privat key is given unaltered + f) The Ed25519 private is supplied as additional argument + */ + +char bufin[1000]; // RFC 5322: 998 chars - why? +buffer bi = BUFFER_INIT(read,0,bufin,sizeof(bufin)); +char bufout[1000]; +buffer bo = BUFFER_INIT(write,1,bufout,sizeof(bufout)); + +void die(int e) { _exit(e); } +void die_write(char *fn) { unlink(fn); die(53); }; +void die_read() { die(54); }; +void out(char *s) { if (buffer_puts(&bo,s) == -1) _exit(111); } +void zero() { if (buffer_put(&bo,"\0",1) == -1) _exit(111); } +void zerodie() { zero(); buffer_flush(&bo); _exit(111); } + +stralloc fndkin = {0}; +stralloc fndkout = {0}; + +stralloc sender = {0}; // will be re-written +stralloc senddomain = {0}; +stralloc originator = {0}; +stralloc dkimdomains = {0}; +struct constmap mapdkimdomains; + +stralloc ecckey = {0}; +stralloc rsakey = {0}; +char *dkimparams = 0; + +void temp_nomem() +{ + out("ZOut of memory. (#4.3.0)\n"); + zerodie(); +} +void temp_chdir() +{ + out("ZUnable to switch to target directory. (#4.3.0)\n"); + zerodie(); +} +void temp_create() +{ + out("ZUnable to create DKIM stage file: "); + out(error_str(errno)); + out(fndkin.s); out(". (#4.3.0)\n"); + zerodie(); +} +void temp_unlink() +{ + out("ZUnable to unlink DKIM stage file. (#4.3.0)\n"); + zerodie(); +} +void temp_control() +{ + out("ZUnable to read DKIM control files. (#4.3.0)\n"); + zerodie(); +} +void perm_usage() +{ + out("Zqmail-dksign was invoked improperly. (#5.3.5)\n"); + zerodie(); +} +void temp_read() +{ + out("DUnable to read message for DKIM signing. (#4.3.0)\n"); + zerodie(); +} +void temp_nosignkey() +{ + out("DCan't read sign key: "); + out(rsakey.s); + out(" or "); + out(ecckey.s); + out(". (#4.3.0)\n"); + zerodie(); +} + +int get_controls() +{ + int i; + stralloc domname = {0}; + + if (control_init() == -1) temp_control(); + + switch (control_readfile(&dkimdomains,"control/dkimdomains",0)) { + case -1: return 0; + case 0: if (!constmap_init(&mapdkimdomains,"",0,1)) temp_nomem(); break; + case 1: if (!constmap_init(&mapdkimdomains,dkimdomains.s,dkimdomains.len,1)) temp_nomem(); break; + } + +/* Check for disabled DKIM send domains */ + + if (!stralloc_copys(&domname,"!")) temp_nomem(); + if (!stralloc_cats(&domname,senddomain.s)) temp_nomem(); + if (constmap(&mapdkimdomains,domname.s,domname.len)) return 0; + +/* Parenting domains; senddomain 0-terminated; lowercase */ + + for (i = 0; i <= senddomain.len; ++i) { + if ((i == 0) || (senddomain.s[i] == '.')) + if ((dkimparams = constmap(&mapdkimdomains,senddomain.s + i,senddomain.len - i - 1))) { + if (!stralloc_copys(&sender,senddomain.s + i)) temp_nomem(); + if (!stralloc_0(&sender)) temp_nomem(); + return 3; + } + } + +/* We sign only senddomains we take responsibility for: rcpthosts */ + + if ((dkimparams = constmap(&mapdkimdomains,"=",1))) { + if (rcpthosts_init() == -1) temp_control(); + if (rcpthosts(originator.s,originator.len)) { + if ((control_readline(&sender,"control/defaultdomain") != 1)) + if (control_readline(&sender,"control/me") == -1) temp_control(); + if (!stralloc_0(&sender)) temp_nomem(); + return 2; + } + } + +/* Default settings for MTA: 'defaultdomain' or even 'me' */ + + if ((dkimparams = constmap(&mapdkimdomains,"*",1))) { + if ((control_readline(&sender,"control/defaultdomain") != 1)) + if (control_readline(&sender,"control/me") == -1) temp_control(); + if (!stralloc_0(&sender)) temp_nomem(); + return 1; + } + + return 0; +} + +void fnmake_dkim(unsigned long id) +{ + fndkin.len = fmtqfn(fndkin.s,"queue/dkim/",id,1); + id += id; + fndkout.len = fmtqfn(fndkout.s,"queue/dkim/",id,1); +} + +void dkim_unlink() +{ + if (unlink(fndkin.s) == -1) + if (errno != ENOENT) temp_unlink(); + if (unlink(fndkout.s) == -1) + if (errno != ENOENT) temp_unlink(); +} + +void dkim_stage() +{ + int r; + int fd; + char ch; + struct stat st; + + if (!stralloc_ready(&fndkin,FMTQFN)) temp_nomem(); + if (!stralloc_ready(&fndkout,FMTQFN)) temp_nomem(); + + fnmake_dkim(getpid()); // pre-staging + dkim_unlink(); // duplicate, left over file + fd = open_excl(fndkin.s); + if (fd == -1) die_write(fndkin.s); + + buffer_init(&bi,read,0,bufin,sizeof(bufin)); + buffer_init(&bo,write,fd,bufout,sizeof(bufout)); + + for (;;) { + r = buffer_get(&bi,&ch,1); + if (r == 0) break; + if (r == -1) temp_read(); + if (ch == '\r') continue; + + while (ch != '\n') { + buffer_put(&bo,&ch,1); + r = buffer_get(&bi,&ch,1); + if (r == -1) temp_read(); + } + buffer_put(&bo,"\r\n",2); + } + + if (buffer_flush(&bo) == -1) die(51); + if (fstat(fd,&st) == -1) die_read(); + if (fsync(fd) == -1) die_write(fndkin.s); + if (close(fd) == -1) die_write(fndkin.s); +} + +/* to construct DKIM information */ + +stralloc selector = {0}; +stralloc selectore = {0}; +stralloc sdid = {0}; +stralloc auid = {0}; +stralloc expire = {0}; +stralloc canon = {0}; // -c r = relax, s = simple, t = relaxed/simple, u = simple/realxed +stralloc hash = {0}; // -z 1/2/3/4/5 sha1/sha2/both/ed25519/ed25519+rsa-sha256 +stralloc length = {0}; // -l + +/** + + qmail-dkim [-h|-v|-s] [tags] [ ] + -------------------------------------------------------------------------------- + tags: + ---- + -c - r=relaxed [DEFAULT], s=simple, t=relaxed/simple, u=simple/relaxed + -d - Signing Domain Identifier,if not provided it will be determined from the envelope originator/from header + -i - Agent User Identifier, usually the sender's email address (optional) + -l - include body length tag (optional) + -q - include query method tag + -t - include a timestamp tag (optional) + -x - the expire time in seconds since epoch (optional, DEFAULT = current time + 604800) + -y - set RSA selector (DEFAULT: default) + -Y - set Ed25519 selector (DEFAULT: default) + -z - set signature type (1=sha1, 2=sha256, 3=both, 4=ed25519, 5=hybrid) +*/ + +int dkim_sign(const char *rsakeyfile,const char *ecckeyfile,const char *fnin,const char *fnout) +{ + int child; + int wstat; + char *(args[17]); + int i = 0; + + args[i] = "qmail-dkim"; ++i; + args[i] = "-s"; ++i; + args[i] = "-q"; ++i; + if (sdid.len > 3) { args[i] = sdid.s; ++i; } + if (selector.len > 3) { args[i] = selector.s; ++i; } + if (selectore.len > 3) { args[i] = selectore.s; ++i; } + if (auid.len > 3) { args[i] = auid.s; ++i; } + if (expire.len > 3) { args[i] = expire.s; ++i; } + if (canon.len > 2) { args[i] = canon.s; ++i; } + if (hash.len > 2) { args[i] = hash.s; ++i; } + if (length.len > 2) { args[i] = length.s; ++i; } + args[i] = fnin; ++i; + args[i] = rsakeyfile; ++i; + args[i] = fnout; ++i; + if (str_len(ecckeyfile) > 3) { args[i] = ecckeyfile; ++i; } + args[i] = 0; + + if (!(child = vfork())) { + pathexec(args); + if (errno) _exit(111); + _exit(100); + } + + wait_pid(&wstat,child); + if (wait_crashed(wstat)) return 1; + + switch (wait_exitcode(wstat)) { + case 1: return 1; + default: return 0; + } +} + +int qmail_remote(char **qargs,int fd) +{ + int child; + int wstat; + char *(args[5]); + + args[0] = "qmail-remote"; + args[1] = qargs[1]; + args[2] = qargs[2]; + args[3] = qargs[3]; + args[4] = 0; + + if (!(child = vfork())) { + if (fd) { + if (fd_move(0,fd) == -1) _exit(111); + if (fd_copy(2,1) == -1) _exit(111); + } + pathexec(args); + if (errno) _exit(111); + _exit(100); + } + + wait_pid(&wstat,child); + if (wait_crashed(wstat)) return 1; + + switch (wait_exitcode(wstat)) { + case 111: return 1; + default: return 0; + } +} + +void dkim_setup() +{ + int c, i, j, k, l; + char *opt, *pos; + + /* defaults: selector=default, IETF format, q=dns/txt, z=2, c=r */ + + if (!stralloc_copys(&sdid,"-d")) temp_nomem(); + if (!stralloc_cat(&sdid,&sender)) temp_nomem(); + if (!stralloc_0(&sdid)) temp_nomem(); + if (!stralloc_copys(&selector,"-ydefault")) temp_nomem(); + if (!stralloc_0(&selector)) temp_nomem(); + if (!stralloc_copys(&selectore,"-Yeddy")) temp_nomem(); + if (!stralloc_0(&selectore)) temp_nomem(); + if (!stralloc_copys(&canon,"-cr")) temp_nomem(); + if (!stralloc_0(&canon)) temp_nomem(); + if (!stralloc_copys(&hash,"-z2")) temp_nomem(); + if (!stralloc_0(&hash)) temp_nomem(); + + /* domain:selector,selectore|sdid|[auid|~]|expire|c:z:l; c=[r|s|t|u], z=[1,2,3,4,5], l=l */ + + if (dkimparams && *dkimparams) { + i = str_chr(dkimparams,'|'); + pos = dkimparams + i; + if (*pos == '|' || *pos == '\0') { // selector + dkimparams[i] = '\0'; + c = str_chr(dkimparams,','); // selectore=eddy + if (dkimparams[c] == ',') { + dkimparams[c] = '\0'; + if (str_len(dkimparams + c + 1)) { + if (!stralloc_copys(&selectore,"-Y")) temp_nomem(); + if (!stralloc_cats(&selectore,dkimparams + c + 1)) temp_nomem(); + if (!stralloc_0(&selectore)) temp_nomem(); + } + } else if (str_len(dkimparams)) { // selector=default + if (!stralloc_copys(&selector,"-y")) temp_nomem(); + if (!stralloc_cats(&selector,dkimparams)) temp_nomem(); + if (!stralloc_0(&selector)) temp_nomem(); + } + + j = str_chr(dkimparams + i + 1,'|'); + pos = dkimparams + i + j + 1; + if (*pos == '|' || *pos == '\0') { // sdid; domain in DKIM header + dkimparams[i + j + 1] = '\0'; + if (!stralloc_copys(&sdid,"-d")) temp_nomem(); + if (!stralloc_cats(&sdid,dkimparams + i + 1)) temp_nomem(); + if (!stralloc_0(&sdid)) temp_nomem(); + + k = str_chr(dkimparams + i + j + 2,'|'); + pos = dkimparams + i + j + k + 2; + if (*pos == '|' || *pos == '\0') { // auid = identifier + dkimparams[i + j + k + 2] = '\0'; + if (!stralloc_copys(&auid,"-i")) temp_nomem(); + if (dkimparams[i + j + 2] == '~') { + if (!stralloc_cat(&auid,&originator)) temp_nomem(); + } else + if (!stralloc_cats(&auid,dkimparams + i + j + 2)) temp_nomem(); + + if (!stralloc_0(&auid)) temp_nomem(); + + l = str_chr(dkimparams + i + j + k + 3,'|'); + pos = dkimparams + i + j + k + l + 3; + if (*pos == '|' || *pos == '\0') { // expire after n secs + dkimparams[i + j + k + l + 3] = '\0'; + if (!stralloc_copys(&expire,"-x")) temp_nomem(); + if (!stralloc_cats(&expire,dkimparams + i + j + k + 3)) temp_nomem(); + if (!stralloc_0(&expire)) temp_nomem(); + + /* Options to follow */ + + opt = dkimparams + i + j + k + l + 4; + if (*opt == '\0') return; + if (*opt != ':') { + if (!stralloc_copys(&canon,"-c")) temp_nomem(); // canonicalization + if (!stralloc_catb(&canon,opt,1)) temp_nomem(); + if (!stralloc_0(&canon)) temp_nomem(); + ++opt; if (*opt == '\0') return; // next colon + } + if (*opt != ':' || *opt == '\0') return; + if (*opt == ':') ++opt; + if (*opt != ':') { + if (!stralloc_copys(&hash,"-z")) temp_nomem(); // hash + if (!stralloc_catb(&hash,opt,1)) temp_nomem(); + if (!stralloc_0(&hash)) temp_nomem(); + ++opt; if (*opt == '\0') return; // next colon + } + if (*opt != ':' || *opt == '\0') return; + if (*opt == ':') ++opt; + if (*opt != ':' && *opt == 'l') { + if (!stralloc_copys(&length,"-l")) temp_nomem(); // length + if (!stralloc_0(&length)) temp_nomem(); + } + } + } + } + } + } + + return; +} + +int main(int argc,char **args) +{ + int i; + int fdin = 0; // initial read from FD 0 + int nkey = 0; + char *(qargs[4]); + struct stat st; + + qargs[0] = args[0]; + qargs[1] = args[1]; // host + qargs[2] = args[2]; // originator + qargs[3] = args[3]; // recipient + + umask(033); + sig_pipeignore(); + if (argc < 4) perm_usage(); + if (chdir(auto_qmail) == -1) temp_chdir(); + + if (str_len(args[2]) > 2) { + i = str_chr(args[2],'@'); + if (*(args[2] + i) == '@') + if (!stralloc_copys(&senddomain,args[2] + i + 1)) temp_nomem(); + } + if (!stralloc_0(&senddomain)) temp_nomem(); + if (!stralloc_copys(&originator,args[2])) temp_nomem(); + + if (!get_controls()) { + qmail_remote(qargs,fdin); + _exit(0); + } + + dkim_setup(); // sender is evaluated from originator (senddomain) + + /* Setup keys: they are composed from selector */ + + case_lowerb(sender.s,sender.len); // needs to be lowercase + if (!stralloc_copys(&rsakey,DOMAINKEYS)) temp_nomem(); + if (!stralloc_cats(&rsakey,sender.s)) temp_nomem(); + if (!stralloc_cats(&rsakey,"/")) temp_nomem(); + + if (!stralloc_copys(&ecckey,DOMAINKEYS)) temp_nomem(); + if (!stralloc_cats(&ecckey,sender.s)) temp_nomem(); + if (!stralloc_cats(&ecckey,"/")) temp_nomem(); + + /* RSA key common for SHA1 and SHA256: rsakeyfile -> selector */ + + if (!stralloc_cats(&rsakey,selector.s + 2)) temp_nomem(); // -y prepended + if (!stralloc_0(&rsakey)) temp_nomem(); + if (stat(rsakey.s,&st) != -1) + if (open_read(rsakey.s) > 0) ++nkey; + + /* ECC key follows: ecckeyfile -> (,)selector2 */ + + if (!stralloc_cats(&ecckey,selectore.s + 2)) temp_nomem(); // -Y prepended + if (!stralloc_0(&ecckey)) temp_nomem(); + if (stat(ecckey.s,&st) != -1) + if (open_read(ecckey.s) > 0) ++nkey; + + /* We got keys - go for staging */ + + if (nkey) { // otherwise no key exists; why bother + dkim_stage(); + if (!dkim_sign(rsakey.s,ecckey.s,fndkin.s,fndkout.s)) { + fdin = open_read(fndkout.s); + if (fdin == -1) die_read(); + } else { + fdin = open_read(fndkin.s); // DKIM key failed to sign + if (fdin == -1) die_read(); + } + } else + temp_nosignkey(); + + qmail_remote(qargs,fdin); // closes fdin + if (nkey) dkim_unlink(); + + _exit(0); +} -- cgit v1.2.3