ref: c1d40df49550393f3afe53fb6e6d500dfa8eb7a8
dir: /sys/src/cmd/auth/ssh2rsa.c/
#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; char *s; 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"); s = smprint("%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); if(s == nil) sysfatal("smprint: %r"); if(write(1, s, strlen(s)) != strlen(s)) sysfatal("write: %r"); exits(nil); }