don't ever set pointer outside of buffer
[oweals/ucert.git] / ucert.c
diff --git a/ucert.c b/ucert.c
index 49d39e9fa58c226aad93d1d48694609b86145b48..6cdc2201fb3933bacfdfbb011102a167571206ee 100644 (file)
--- a/ucert.c
+++ b/ucert.c
@@ -47,6 +47,11 @@ static enum {
 } cmd = CMD_NONE;
 
 static bool quiet;
+#ifndef UCERT_STRIP_MESSAGES
+#define DPRINTF(format, ...) if (!quiet) fprintf(stderr, "%s(%d): " format, __func__, __LINE__, ## __VA_ARGS__)
+#else
+#define DPRINTF(format, ...)
+#endif
 
 /*
  * ucert structure
@@ -167,13 +172,13 @@ static int cert_load(const char *certfile, struct list_head *chain) {
 
                list_add_tail(&cobj->list, chain);
                ret += pret;
-               bufpt = blob_next(bufpt);
        /* repeat parsing while there is still enough remaining data in buffer */
-       } while(len > pos + sizeof(struct blob_attr));
+       } while(len > pos + sizeof(struct blob_attr) && (bufpt = blob_next(bufpt)));
 
        return (ret <= 0);
 }
 
+#ifdef UCERT_FULL
 /* append signature to certfile */
 static int cert_append(const char *certfile, const char *sigfile) {
        FILE *fs;
@@ -198,6 +203,7 @@ static int cert_append(const char *certfile, const char *sigfile) {
        blob_buf_free(&sigbuf);
        return ret;
 }
+#endif
 
 /* verify the signature of a single chain element */
 static int cert_verify_blob(struct blob_attr *cert[CERT_ATTR_MAX],
@@ -250,6 +256,7 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
        char extsigfile[256] = {0};
        int ret = 1;
        int checkmsg = 0;
+       struct timeval tv;
 
        if (mkdtemp(tmpdir) == NULL)
                return errno;
@@ -257,10 +264,11 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
        if (msgfile)
                checkmsg = -1;
 
+       gettimeofday(&tv, NULL);
+
        list_for_each_entry(cobj, chain, list) {
                /* blob has payload, verify that using signature */
                if (cobj->cert[CERT_ATTR_PAYLOAD]) {
-                       struct timeval tv;
                        uint64_t validfrom;
                        uint64_t expiresat;
                        uint32_t certtype;
@@ -276,7 +284,7 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
                                      blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
                        if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
                                ret = 1;
-                               fprintf(stderr, "no ucert in signed payload\n");
+                               DPRINTF("no ucert in signed payload\n");
                                goto clean_and_return;
                        }
                        blobmsg_parse(cert_payload_policy,
@@ -290,7 +298,7 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
                            !payloadtb[CERT_PL_ATTR_EXPIRETIME] ||
                            !payloadtb[CERT_PL_ATTR_PUBKEY]) {
                                ret = 1;
-                               fprintf(stderr, "missing mandatory ucert attributes\n");
+                               DPRINTF("missing mandatory ucert attributes\n");
                                goto clean_and_return;
                        }
                        certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
@@ -299,15 +307,14 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
 
                        if (certtype != CERTTYPE_AUTH) {
                                ret = 2;
-                               fprintf(stderr, "wrong certificate type\n");
+                               DPRINTF("wrong certificate type\n");
                                goto clean_and_return;
                        }
 
-                       gettimeofday(&tv, NULL);
                        if (tv.tv_sec < validfrom ||
                            tv.tv_sec >= expiresat) {
                                ret = 3;
-                               fprintf(stderr, "certificate expired\n");
+                               DPRINTF("certificate expired\n");
                                goto clean_and_return;
                        }
 
@@ -318,14 +325,12 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
                                   false);
 
                        if (usign_f_pubkey(chainedfp, chainedpubkey)) {
-                               if (!quiet)
-                                       fprintf(stderr, "cannot get fingerprint for chained key\n");
+                               DPRINTF("cannot get fingerprint for chained key\n");
                                ret = 2;
                                goto clean_and_return;
                        }
                        if (pubkeydir && _usign_key_is_revoked(chainedfp, pubkeydir)) {
-                               if (!quiet)
-                                       fprintf(stderr, "key %s has been revoked!\n", chainedfp);
+                               DPRINTF("key %s has been revoked!\n", chainedfp);
                                ret = 4;
                                goto clean_and_return;
                        }
@@ -342,14 +347,14 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
                                              pubkeydir, extsigfile, quiet);
                                unlink(extsigfile);
                        } else {
-                               fprintf(stderr, "stray trailing signature without anything to verify!\n");
+                               DPRINTF("stray trailing signature without anything to verify!\n");
                                ret = 1;
                        };
                }
        }
 
        if (checkmsg == -1)
-               fprintf(stderr, "missing signature to verify message!\n");
+               DPRINTF("missing signature to verify message!\n");
 
 clean_and_return:
        if (chainedpubkey[0])
@@ -358,6 +363,7 @@ clean_and_return:
        return ret | checkmsg;
 }
 
+#ifdef UCERT_FULL
 /* dump single chain element to console */
 static void cert_dump_blob(struct blob_attr *cert[CERT_ATTR_MAX]) {
        int i;
@@ -386,14 +392,13 @@ static int cert_dump(const char *certfile) {
        unsigned int count = 0;
 
        if (cert_load(certfile, &certchain)) {
-               fprintf(stderr, "cannot parse cert\n");
+               DPRINTF("cannot parse cert\n");
                return 1;
        }
 
        list_for_each_entry(cobj, &certchain, list) {
-               fprintf(stderr, "=== CHAIN ELEMENT %02u ===\n", ++count);
+               fprintf(stdout, "=== CHAIN ELEMENT %02u ===\n", ++count);
                cert_dump_blob(cobj->cert);
-               fprintf(stderr, "========================\n");
        }
 
        return 0;
@@ -404,7 +409,6 @@ static int cert_issue(const char *certfile, const char *pubkeyfile, const char *
        struct blob_buf certbuf;
        struct blob_buf payloadbuf;
        struct timeval tv;
-       struct stat st;
        int pklen, siglen;
        int revoker = 1;
        void *c;
@@ -415,11 +419,6 @@ static int cert_issue(const char *certfile, const char *pubkeyfile, const char *
        char pkfp[17];
        char tmpdir[] = "/tmp/ucert-XXXXXX";
 
-       if (stat(certfile, &st) == 0) {
-               fprintf(stderr, "certfile %s exists, won't overwrite.\n", certfile);
-               return -1;
-       }
-
        pkf = fopen(pubkeyfile, "r");
        if (!pkf)
                return -1;
@@ -479,7 +478,7 @@ static int cert_issue(const char *certfile, const char *pubkeyfile, const char *
                blob_put(&certbuf, CERT_ATTR_SIGNATURE, sigb, siglen);
                blob_put(&certbuf, CERT_ATTR_PAYLOAD, blob_data(payloadbuf.head), blob_len(payloadbuf.head));
                snprintf(fname, sizeof(fname) - 1, "%s%s", certfile, revoker?".revoke":"");
-               write_file(fname, certbuf.head, blob_raw_len(certbuf.head), false);
+               write_file(fname, certbuf.head, blob_raw_len(certbuf.head), true);
                blob_buf_free(&certbuf);
                blob_buf_free(&payloadbuf);
 
@@ -490,6 +489,7 @@ static int cert_issue(const char *certfile, const char *pubkeyfile, const char *
 
        return 0;
 }
+#endif
 
 /* process revoker certificate */
 static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
@@ -507,14 +507,17 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
        int ret;
 
        if (cert_load(certfile, &certchain)) {
-               fprintf(stderr, "cannot parse cert\n");
+               DPRINTF("cannot parse cert\n");
                return 1;
        }
 
+       gettimeofday(&tv, NULL);
+
        list_for_each_entry(cobj, &certchain, list) {
-               /* blob has payload, verify that using signature */
                if (!cobj->cert[CERT_ATTR_PAYLOAD])
                        return 2;
+
+               /* blob has payload, verify that using signature */
                ret = cert_verify_blob(cobj->cert, NULL, pubkeydir);
                if (ret)
                        return ret;
@@ -525,7 +528,7 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
                              blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
                              blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
                if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
-                       fprintf(stderr, "no ucert in signed payload\n");
+                       DPRINTF("no ucert in signed payload\n");
                        return 2;
                }
 
@@ -538,7 +541,7 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
                if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
                    !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
                    !payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]) {
-                       fprintf(stderr, "missing mandatory ucert attributes\n");
+                       DPRINTF("missing mandatory ucert attributes\n");
                        return 2;
                }
 
@@ -547,11 +550,10 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
                fingerprint = blobmsg_get_string(payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]);
 
                if (certtype != CERTTYPE_REVOKE) {
-                       fprintf(stderr, "wrong certificate type\n");
+                       DPRINTF("wrong certificate type\n");
                        return 2;
                }
 
-               gettimeofday(&tv, NULL);
                if (tv.tv_sec < validfrom) {
                        return 3;
                }
@@ -560,8 +562,7 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
                /* check if entry in pubkeydir exists */
                if (stat(rfname, &st) == 0) {
                        if (_usign_key_is_revoked(fingerprint, pubkeydir)) {
-                               if (!quiet)
-                                       fprintf(stdout, "existing revoker deadlink for key %s\n", fingerprint);
+                               DPRINTF("existing revoker deadlink for key %s\n", fingerprint);
                                continue;
                        };
 
@@ -574,8 +575,7 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
                if (ret)
                        return ret;
 
-               if (!quiet)
-                       fprintf(stdout, "created revoker deadlink for key %s\n", fingerprint);
+               DPRINTF("created revoker deadlink for key %s\n", fingerprint);
        };
 
        return ret;
@@ -586,7 +586,7 @@ static int cert_verify(const char *certfile, const char *pubkeyfile, const char
        static LIST_HEAD(certchain);
 
        if (cert_load(certfile, &certchain)) {
-               fprintf(stderr, "cannot parse cert\n");
+               DPRINTF("cannot parse cert\n");
                return 1;
        }
 
@@ -596,12 +596,15 @@ static int cert_verify(const char *certfile, const char *pubkeyfile, const char
 /* output help */
 static int usage(const char *cmd)
 {
+#ifndef UCERT_STRIP_MESSAGES
        fprintf(stderr,
                "Usage: %s <command> <options>\n"
                "Commands:\n"
+#ifdef UCERT_FULL
                "  -A:                  append signature (needs -c and -x)\n"
                "  -D:                  dump (needs -c)\n"
                "  -I:                  issue cert and revoker (needs -c and -p and -s)\n"
+#endif /* UCERT_FULL */
                "  -R:                  process revoker certificate (needs -c and -P)\n"
                "  -V:                  verify (needs -c and -p|-P, may have -m)\n"
                "Options:\n"
@@ -610,10 +613,13 @@ static int usage(const char *cmd)
                "  -p <file>:           public key file\n"
                "  -P <path>:           public key directory (verify only)\n"
                "  -q:                  quiet (do not print verification result, use return code only)\n"
+#ifdef UCERT_FULL
                "  -s <file>:           secret key file (issue only)\n"
-               "  -x <file>:           signature file\n"
+               "  -x <file>:           signature file (append only)\n"
+#endif /* UCERT_FULL */
                "\n",
                cmd);
+#endif /* UCERT_STRIP_MESSAGES */
        return 1;
 }
 
@@ -621,15 +627,23 @@ static int usage(const char *cmd)
 int main(int argc, char *argv[]) {
        int ch;
        const char *msgfile = NULL;
-       const char *sigfile = NULL;
        const char *pubkeyfile = NULL;
        const char *pubkeydir = NULL;
        const char *certfile = NULL;
+#ifdef UCERT_FULL
+       const char *sigfile = NULL;
        const char *seckeyfile = NULL;
+#endif
 
        quiet = false;
-       while ((ch = getopt(argc, argv, "ADIRVc:m:p:P:qs:x:")) != -1) {
+       while ((ch = getopt(argc, argv,
+               "RVc:m:p:P:q"
+#ifdef UCERT_FULL
+               "ADIs:x:"
+#endif
+              )) != -1) {
                switch (ch) {
+#ifdef UCERT_FULL
                case 'A':
                        if (cmd != CMD_NONE)
                                return usage(argv[0]);
@@ -645,6 +659,7 @@ int main(int argc, char *argv[]) {
                                return usage(argv[0]);
                        cmd = CMD_ISSUE;
                        break;
+#endif
                case 'R':
                        if (cmd != CMD_NONE)
                                return usage(argv[0]);
@@ -676,10 +691,11 @@ int main(int argc, char *argv[]) {
                        pubkeydir = optarg;
                        break;
                case 'q':
-                       if (quiet || cmd == CMD_NONE)
+                       if (quiet)
                                return usage(argv[0]);
                        quiet = true;
                        break;
+#ifdef UCERT_FULL
                case 's':
                        if (seckeyfile || cmd != CMD_ISSUE || cmd == CMD_NONE)
                                return usage(argv[0]);
@@ -690,12 +706,14 @@ int main(int argc, char *argv[]) {
                                return usage(argv[0]);
                        sigfile = optarg;
                        break;
+#endif
                default:
                        return usage(argv[0]);
                }
        }
 
        switch (cmd) {
+#ifdef UCERT_FULL
        case CMD_APPEND:
                if (certfile && sigfile)
                        return cert_append(certfile, sigfile);
@@ -711,6 +729,7 @@ int main(int argc, char *argv[]) {
                        return cert_issue(certfile, pubkeyfile, seckeyfile);
                else
                        return usage(argv[0]);
+#endif
        case CMD_REVOKE:
                if (certfile && pubkeydir)
                        return cert_process_revoker(certfile, pubkeydir);
@@ -721,7 +740,7 @@ int main(int argc, char *argv[]) {
                        return cert_verify(certfile, pubkeyfile, pubkeydir, msgfile);
                else
                        return usage(argv[0]);
-       case CMD_NONE:
+       default:
                return usage(argv[0]);
        }