ref: 86e0099835f99de6ccc3bee33a297387993aa037
dir: /sys/src/cmd/ssh/pubkey.c/
#include "ssh.h" #include <bio.h> #include <ctype.h> static int parsepubkey(char *s, RSApub *key, char **sp, int base) { int n; char *host, *p, *z; z = nil; n = strtoul(s, &p, 10); host = nil; if(n < 256 || !isspace(*p)){ /* maybe this is a host name */ host = s; s = strpbrk(s, " \t"); if(s == nil) return -1; z = s; *s++ = '\0'; s += strspn(s, " \t"); n = strtoul(s, &p, 10); if(n < 256 || !isspace(*p)){ if(z) *z = ' '; return -1; } } if((key->ek = strtomp(p, &p, base, nil)) == nil || (key->n = strtomp(p, &p, base, nil)) == nil || (*p != '\0' && !isspace(*p)) || mpsignif(key->n) < 256){ /* 256 is just a sanity check */ mpfree(key->ek); mpfree(key->n); key->ek = nil; key->n = nil; if(z) *z = ' '; return -1; } if(host == nil){ if(*p != '\0'){ p += strspn(p, " \t"); if(*p != '\0'){ host = emalloc(strlen(p)+1); strcpy(host, p); } } free(s); } *sp = host; return 0; } RSApub* readpublickey(Biobuf *b, char **sp) { char *s; RSApub *key; key = rsapuballoc(); if(key == nil) return nil; for(;;){ if((s = Brdstr(b, '\n', 1)) == nil){ rsapubfree(key); return nil; } if(s[0]=='#'){ free(s); continue; } if(parsepubkey(s, key, sp, 10)==0 || parsepubkey(s, key, sp, 16)==0) return key; fprint(2, "warning: skipping line '%s'; cannot parse\n", s); free(s); } } static int match(char *pattern, char *aliases) { char *s, *snext; char *a, *anext, *ae; for(s=pattern; s && *s; s=snext){ if((snext=strchr(s, ',')) != nil) *snext++ = '\0'; for(a=aliases; a && *a; a=anext){ if((anext=strchr(a, ',')) != nil){ ae = anext; anext++; }else ae = a+strlen(a); if(ae-a == strlen(s) && memcmp(s, a, ae-a)==0) return 0; } } return 1; } int findkey(char *keyfile, char *host, RSApub *key) { char *h; Biobuf *b; RSApub *k; if((b = Bopen(keyfile, OREAD)) == nil) return NoKeyFile; for(;;){ if((k = readpublickey(b, &h)) == nil){ Bterm(b); return NoKey; } if(match(h, host) != 0){ free(h); rsapubfree(k); continue; } if(mpcmp(k->n, key->n) != 0 || mpcmp(k->ek, key->ek) != 0){ free(h); rsapubfree(k); Bterm(b); return KeyWrong; } free(h); rsapubfree(k); Bterm(b); return KeyOk; } } int replacekey(char *keyfile, char *host, RSApub *hostkey) { char *h, *nkey, *p; Biobuf *br, *bw; Dir *d, nd; RSApub *k; nkey = smprint("%s.new", keyfile); if(nkey == nil) return -1; if((br = Bopen(keyfile, OREAD)) == nil){ free(nkey); return -1; } if((bw = Bopen(nkey, OWRITE)) == nil){ Bterm(br); free(nkey); return -1; } while((k = readpublickey(br, &h)) != nil){ if(match(h, host) != 0){ Bprint(bw, "%s %d %.10B %.10B\n", h, mpsignif(k->n), k->ek, k->n); } free(h); rsapubfree(k); } Bprint(bw, "%s %d %.10B %.10B\n", host, mpsignif(hostkey->n), hostkey->ek, hostkey->n); Bterm(bw); Bterm(br); d = dirstat(nkey); if(d == nil){ fprint(2, "new key file disappeared?\n"); free(nkey); return -1; } p = strrchr(d->name, '.'); if(p==nil || strcmp(p, ".new")!=0){ fprint(2, "new key file changed names? %s to %s\n", nkey, d->name); free(d); free(nkey); return -1; } *p = '\0'; nulldir(&nd); nd.name = d->name; if(remove(keyfile) < 0){ fprint(2, "error removing %s: %r\n", keyfile); free(d); free(nkey); return -1; } if(dirwstat(nkey, &nd) < 0){ fprint(2, "error renaming %s to %s: %r\n", nkey, d->name); free(nkey); free(d); return -1; } free(d); free(nkey); return 0; } int appendkey(char *keyfile, char *host, RSApub *key) { int fd; if((fd = open(keyfile, OWRITE)) < 0){ fd = create(keyfile, OWRITE, 0666); if(fd < 0){ fprint(2, "cannot open nor create %s: %r\n", keyfile); return -1; } } if(seek(fd, 0, 2) < 0 || fprint(fd, "%s %d %.10B %.10B\n", host, mpsignif(key->n), key->ek, key->n) < 0){ close(fd); return -1; } close(fd); return 0; }