ref: 54bac038f411c10a596adf84c06df32f8c7c4c53
dir: /os/port/devsign.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "interp.h"
#include <isa.h>
#include "runt.h"
#include "mp.h"
#include "libsec.h"
#include "../../libkeyring/keys.h"
/*
* experimental version of signed modules
*/
enum
{
Qdir,
Qkey,
Qctl,
Maxkey = 2048
};
static Dirtab signdir[] =
{
".", {Qdir, 0, QTDIR}, 0, DMDIR|0555,
"signerkey", {Qkey}, 0, 0644,
"signerctl", {Qctl}, 0, 0600,
};
typedef struct Get Get;
struct Get {
uchar* p;
uchar* ep;
};
#define G32(b) ((b[0]<<24)|(b[1]<<16)|(b[2]<<8)|b[3])
static int vc(Get*);
static int vs(void*, int, Get*, int);
static Signerkey* findsignerkey(Skeyset*, char*, int, char*);
extern vlong osusectime(void);
int
verifysigner(uchar *sign, int len, uchar *data, ulong ndata)
{
Get sig;
int alg;
ulong issued, expires, now;
int footprint, r, n;
uchar buf[128], digest[SHA1dlen];
DigestState *ds;
volatile struct {BigInt b;} b;
volatile struct {BigInt s;} s;
SigAlgVec *sa;
Signerkey *key;
Skeyset *sigs;
/* alg[1] issued[4] expires[4] footprint[2] signer[n] sig[m] */
sigs = up->env->sigs;
if(sigs == nil)
return 1; /* not enforcing signed modules */
sig.p = sign;
sig.ep = sign+len;
alg = vc(&sig);
if(alg != 2)
return 0; /* we do only SHA1/RSA */
sa = findsigalg("rsa");
if(sa == nil)
return 0;
if(vs(buf, sizeof(buf), &sig, 4) < 0)
return 0;
now = osusectime()/1000000;
issued = G32(buf);
if(vs(buf, sizeof(buf), &sig, 4) < 0)
return 0;
if(issued != 0 && now < issued)
return 0;
expires = G32(buf);
if(expires != 0 && now >= expires)
return 0;
footprint = vc(&sig) << 8;
footprint |= vc(&sig);
if(footprint < 0)
return 0;
r = 0;
b.b = nil;
s.s = nil;
qlock(sigs);
if(waserror())
goto out;
if((n = vs(buf, sizeof(buf)-NUMSIZE-1, &sig, -1)) < 0) /* owner */
goto out;
buf[n] = 0;
key = findsignerkey(sigs, sa->name, footprint, (char*)buf);
if(key == nil)
goto out;
n += snprint((char*)buf+n, NUMSIZE, " %lud", expires);
ds = sha1(buf, n, nil, nil);
sha1(data, ndata, digest, ds);
b.b = betomp(digest, SHA1dlen, nil);
if(b.b == nil)
goto out;
s.s = betomp(sig.p, sig.ep-sig.p, nil);
if(s.s == nil)
goto out;
r = (*sa->verify)(b.b, s.s, key->pk);
out:
qunlock(sigs);
if(b.b != nil)
mpfree(b.b);
if(s.s != nil)
mpfree(s.s);
return r;
}
int
mustbesigned(char *path, uchar*, ulong, Dir *dir)
{
USED(path);
if(0)print("load %s: %d %C\n", path, up->env->sigs!=nil, dir==nil?'?':dir->type);
/* allow only signed modules and those in #/; already loaded modules are reloaded from cache */
return up->env->sigs != nil && (dir == nil || dir->type != '/');
}
static int
vc(Get *g)
{
return g->p < g->ep? *g->p++: -1;
}
static int
vs(void *s, int lim, Get *g, int n)
{
int nr;
if(n < 0){
if(g->p >= g->ep)
return -1;
n = *g->p++;
lim--;
}
if(n > lim)
return -1;
nr = g->ep - g->p;
if(n > nr)
return -1;
if(s != nil)
memmove(s, g->p, n);
g->p += n;
return n;
}
static char*
cstring(char *str, char **strp)
{
char *p, *s;
int n;
p = strchr(str, '\n');
if(p == 0)
p = str + strlen(str);
n = p - str;
s = malloc(n+1);
if(s == nil)
return nil;
memmove(s, str, n);
s[n] = 0;
if(strp){
if(*p)
p++;
*strp = p;
}
return s;
}
static SigAlgVec*
cstrtoalg(char *str, char **strp)
{
int n;
char *p, name[KNAMELEN];
p = strchr(str, '\n');
if(p == 0){
p = str + strlen(str);
if(strp)
*strp = p;
} else {
if(strp)
*strp = p+1;
}
n = p - str;
if(n >= sizeof(name))
return nil;
strncpy(name, str, n);
name[n] = 0;
return findsigalg(name);
}
static Signerkey*
strtopk(char *buf)
{
SigAlgVec *sa;
char *p;
Signerkey *key;
key = malloc(sizeof(*key));
if(key == nil)
return nil;
key->ref = 1;
sa = cstrtoalg(buf, &p);
if(sa == nil){
free(key);
return nil;
}
key->alg = sa;
key->pkfree = sa->pkfree;
key->owner = cstring(p, &p);
if(key->owner == nil){
free(key);
return nil;
}
key->pk = (*sa->str2pk)(p, &p);
if(key->pk == nil){
free(key->owner);
free(key);
return nil;
}
return key;
}
static Signerkey*
findsignerkey(Skeyset *sigs, char *alg, int footprint, char *owner)
{
int i;
Signerkey *key;
for(i=0; i<sigs->nkey; i++){
key = sigs->keys[i];
if(key->footprint == footprint &&
strcmp(alg, ((SigAlgVec*)key->alg)->name) == 0 &&
strcmp(key->owner, owner) == 0)
return key;
}
return nil;
}
static Chan*
signattach(char *spec)
{
return devattach(L'Σ', spec);
}
static Walkqid*
signwalk(Chan *c, Chan *nc, char **name, int nname)
{
return devwalk(c, nc, name, nname, signdir, nelem(signdir), devgen);
}
static int
signstat(Chan *c, uchar *db, int n)
{
return devstat(c, db, n, signdir, nelem(signdir), devgen);
}
static Chan*
signopen(Chan *c, int omode)
{
if(c->qid.type & QTDIR) {
if(omode != OREAD)
error(Eisdir);
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
return c;
}
switch((ulong)c->qid.path){
case Qctl:
if(!iseve())
error(Eperm);
break;
case Qkey:
if(omode != OREAD && !iseve())
error(Eperm);
break;
}
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
return c;
}
static void
signclose(Chan *c)
{
USED(c);
}
static long
signread(Chan *c, void *va, long n, vlong offset)
{
char *buf, *p;
SigAlgVec *sa;
Skeyset *sigs;
Signerkey *key;
int i;
if(c->qid.type & QTDIR)
return devdirread(c, va, n, signdir, nelem(signdir), devgen);
sigs = up->env->sigs;
if(sigs == nil)
return 0;
switch((ulong)c->qid.path){
case Qkey:
buf = smalloc(Maxkey);
if(waserror()){
free(buf);
nexterror();
}
qlock(sigs);
if(waserror()){
qunlock(sigs);
nexterror();
}
p = buf;
for(i=0; i<sigs->nkey; i++){
key = sigs->keys[i];
sa = key->alg;
p = seprint(p, buf+Maxkey, "owner=%s alg=%s footprint=%ud expires=%lud\n",
key->owner, sa->name, key->footprint, key->expires);
}
poperror();
qunlock(sigs);
n = readstr(offset, va, n, buf);
poperror();
free(buf);
return n;
case Qctl:
return readnum(offset, va, n, sigs->nkey, NUMSIZE);
}
return 0;
}
static long
signwrite(Chan *c, void *va, long n, vlong offset)
{
char *buf;
Skeyset *sigs;
Signerkey *okey, *key;
int i;
if(c->qid.type & QTDIR)
error(Eisdir);
USED(offset);
switch((ulong)c->qid.path){
case Qkey:
if(n >= Maxkey)
error(Etoobig);
buf = smalloc(Maxkey);
if(waserror()){
free(buf);
nexterror();
}
memmove(buf, va, n);
buf[n] = 0;
key = strtopk(buf);
if(key == nil)
error("bad key syntax");
poperror();
free(buf);
if(waserror()){
freeskey(key);
nexterror();
}
sigs = up->env->sigs;
if(sigs == nil){
sigs = malloc(sizeof(*sigs));
if(sigs == nil)
error(Enomem);
sigs->ref = 1;
up->env->sigs = sigs;
}
qlock(sigs);
if(waserror()){
qunlock(sigs);
nexterror();
}
for(i=0; i<sigs->nkey; i++){
okey = sigs->keys[i];
if(strcmp(okey->owner, key->owner) == 0){
/* replace existing key */
sigs->keys[i] = key;
freeskey(okey);
break;
}
}
if(i >= sigs->nkey){
if(sigs->nkey >= nelem(sigs->keys))
error("too many keys");
sigs->keys[sigs->nkey++] = key;
}
poperror();
qunlock(sigs);
poperror(); /* key */
return n;
case Qctl:
error(Ebadctl);
break;
}
return 0;
}
Dev signdevtab = {
L'Σ',
"sign",
devreset,
devinit,
devshutdown,
signattach,
signwalk,
signstat,
signopen,
devcreate,
signclose,
signread,
devbread,
signwrite,
devbwrite,
devremove,
devwstat
};