/* $OpenBSD: verify.c,v 1.2 2005/05/28 08:07:45 marius Exp $ */ /* * verify.c * * Copyright (c) 2001 Dug Song * Copyright (c) 2001 Arbor Networks, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The names of the copyright holders may not be used to endorse or * promote products derived from this software without specific * prior written permission. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * $Vendor: verify.c,v 1.3 2005/04/07 23:19:35 dugsong Exp $ */ #include #include #include #include #include #include #include #include #include #include "extern.h" #include "gzip.h" #include "key.h" #include "util.h" static int verify_signature(struct key *key, FILE *fin) { struct gzip_header gh; struct gzip_xfield *gx; struct gzsig_data *gd; u_char *sig, digest[20], buf[8192], sbuf[4096]; SHA_CTX ctx; int i, siglen; /* Read gzip header. */ if ((i = fread((u_char *)&gh, 1, sizeof(gh), fin)) != sizeof(gh)) { fprintf(stderr, "Error reading gzip header: %s\n", strerror(errno)); return (-1); } /* Verify gzip header. */ if (memcmp(gh.magic, GZIP_MAGIC, sizeof(gh.magic)) != 0) { fprintf(stderr, "Invalid gzip file\n"); return (-1); } else if (gh.flags & GZIP_FCONT){ fprintf(stderr, "Multi-part gzip files not supported\n"); return (-1); } else if ((gh.flags & GZIP_FEXTRA) == 0) { fprintf(stderr, "No gzip signature found\n"); return (-1); } /* Read signature. */ gx = (struct gzip_xfield *)buf; if ((i = fread((u_char *)gx, 1, sizeof(*gx), fin)) != sizeof(*gx)) { fprintf(stderr, "Error reading extra field: %s\n", strerror(errno)); return (-1); } if (memcmp(gx->subfield.id, GZSIG_ID, sizeof(gx->subfield.id)) != 0) { fprintf(stderr, "Unknown extra field\n"); return (-1); } gx->subfield.len = letoh16(gx->subfield.len); if (gx->subfield.len <= 0 || gx->subfield.len > sizeof(sbuf)) { fprintf(stderr, "Invalid signature length\n"); return (-1); } gd = (struct gzsig_data *)sbuf; if ((i = fread((u_char *)gd, 1, gx->subfield.len, fin)) != gx->subfield.len) { fprintf(stderr, "Error reading signature: %s\n", strerror(errno)); return (-1); } /* Skip over any options. */ if (gh.flags & GZIP_FNAME) { while (getc(fin) != '\0') ; } if (gh.flags & GZIP_FCOMMENT) { while (getc(fin) != '\0') ; } if (gh.flags & GZIP_FENCRYPT && fread(buf, 1, GZIP_FENCRYPT_LEN, fin) != GZIP_FENCRYPT_LEN) return (-1); /* Check signature version. */ if (gd->version != GZSIG_VERSION) { fprintf(stderr, "Unknown signature version: %d\n", gd->version); return (-1); } /* Compute SHA1 checksum over compressed data and trailer. */ sig = (u_char *)(gd + 1); siglen = gx->subfield.len - sizeof(*gd); SHA1_Init(&ctx); while ((i = fread(buf, 1, sizeof(buf), fin)) > 0) { SHA1_Update(&ctx, buf, i); } SHA1_Final(digest, &ctx); /* Verify signature. */ if (key_verify(key, digest, sizeof(digest), sig, siglen) < 0) { fprintf(stderr, "Error verifying signature\n"); return (-1); } return (0); } void verify_usage(void) { fprintf(stderr, "Usage: gzsig verify [-v] pubkey [file ...]\n"); } void verify(int argc, char *argv[]) { struct key *key; char *gzipfile; FILE *fin; int i, error, vflag; vflag = 0; while ((i = getopt(argc, argv, "vh?")) != -1) { switch (i) { case 'v': vflag = 1; break; default: verify_usage(); exit(1); } } argc -= optind; argv += optind; if (argc < 1) { verify_usage(); exit(1); } OpenSSL_add_all_algorithms(); if ((key = key_new()) == NULL) fatal(1, "Can't initialize public key"); if (key_load_public(key, argv[0]) < 0) fatal(1, "Can't load public key"); if (argc == 1 || *argv[1] == '-') { argc = 0; if (verify_signature(key, stdin) == 0) { if (vflag) fprintf(stderr, "Verified input\n"); } else fatal(1, "Couldn't verify input"); } for (i = 1; i < argc; i++) { gzipfile = argv[i]; if ((fin = fopen(gzipfile, "r")) < 0) { fprintf(stderr, "Couldn't open %s: %s\n", gzipfile, strerror(errno)); continue; } error = verify_signature(key, fin); fclose(fin); if (!error) { if (vflag) fprintf(stderr, "Verified %s\n", gzipfile); } else fatal(1, "Couldn't verify %s", gzipfile); } key_free(key); }