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#include <u.h>
#include <libc.h>
#include <auth.h>
#include <mp.h>
#include <libsec.h>
#define GET4(p) (u32int)(p)[3] | (u32int)(p)[2]<<8 | (u32int)(p)[1]<<16 | (u32int)(p)[0]<<24
static char *magic = "openssh-key-v1";
static uchar *pubkey;
static uchar *pubend;
static uchar *privkey;
static uchar *privend;
static void*
emalloc(ulong size, int clr)
{
void *p;
if((p = mallocz(size, clr)) == nil)
sysfatal("emalloc: %r");
return p;
}
static long
ereadn(int fd, void *buf, long nbytes)
{
long n;
if((n = readn(fd, buf, nbytes)) != nbytes)
sysfatal("ereadn: %r");
return n;
}
static uchar*
slurp(int fd, int alloc, u32int *np)
{
u32int n;
uchar buf[4], trash[1024];
uchar *p;
ereadn(fd, buf, sizeof buf);
n = GET4(buf);
if(alloc){
*np = n;
p = emalloc(n, 0);
ereadn(fd, p, n);
return p;
}
if(n >= sizeof trash)
sysfatal("key component too large");
ereadn(fd, trash, n);
return nil;
}
static u32int
decode(int fd)
{
uchar buf[4];
u32int ret, n;
/* ciphername */
slurp(fd, 0, nil);
/* kdfname */
slurp(fd, 0, nil);
/* kdfoptions */
slurp(fd, 0, nil);
ereadn(fd, buf, 4);
ret = GET4(buf);
pubkey = slurp(fd, 1, &n);
pubend = pubkey + n;
privkey = slurp(fd, 1, &n);
privend = privkey + n;
return ret;
}
static u32int
scan(uchar **p, uchar *e)
{
u32int n;
if(*p + 4 > e)
sysfatal("unexpected end of key");
n = GET4(*p); *p += 4;
if(*p + n > e)
sysfatal("unexpected end of key");
return n;
}
static mpint*
scanmp(uchar **p, uchar *e)
{
mpint *m;
u32int n;
n = scan(p, e);
if(n == 0)
sysfatal("required key component has zero length");
m = betomp(*p, n, nil);
if(m == nil)
sysfatal("betomp: %r");
*p += n;
return m;
}
static RSApriv*
fill(void)
{
char *rsa = "ssh-rsa";
u32int n, a, b;
uchar *p, *e;
mpint *ek, *mod, *dk, *p0, *q0;
p = pubkey;
e = pubend;
if(scan(&p, e) != 7 || memcmp(rsa, p, 7) != 0)
sysfatal("not a RSA key");
p += 7;
ek = scanmp(&p, e);
mod = scanmp(&p, e);
p = privkey;
e = privend;
if(p + 8 >= e)
sysfatal("unexpected end of key");
a = GET4(p); p += 4;
b = GET4(p); p += 4;
if(a != b)
sysfatal("private key seems encrypted");
if(scan(&p, e) != 7 || memcmp(rsa, p, 7) != 0)
sysfatal("not a RSA key");
p += 7;
/* public components are repeated */
n = scan(&p, e); p += n;
n = scan(&p, e); p += n;
dk = scanmp(&p, e);
/* iq */
n = scan(&p, e); p += n;
p0 = scanmp(&p, e);
q0 = scanmp(&p, e);
return rsafill(mod, ek, dk, p0, q0);
}
void
usage(void)
{
fprint(2, "usage: auth/ssh2rsa [file]\n");
exits("usage");
}
void
main(int argc, char **argv)
{
int fd;
RSApriv *p;
uchar buf[64];
fd = 0;
fmtinstall('B', mpfmt);
ARGBEGIN{
default:
usage();
}ARGEND
switch(argc){
default:
usage();
case 1:
fd = open(argv[0], OREAD);
if(fd < 0)
sysfatal("open: %r");
case 0:
break;
}
ereadn(fd, buf, strlen(magic)+1);
if(memcmp(buf, magic, strlen(magic)+1) != 0)
sysfatal("bad magic");
if(decode(fd) != 1)
sysfatal("invalid key");
if((p = fill()) == nil)
sysfatal("fill: %r");
print("%s size=%d ek=%B !dk=%B n=%B !p=%B !q=%B !kp=%B !kq=%B !c2=%B\n",
"key service=ssh proto=rsa",
mpsignif(p->pub.n), p->pub.ek,
p->dk, p->pub.n, p->p, p->q,
p->kp, p->kq, p->c2);
exits(nil);
}
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