From: Daniel Golle <daniel@makrotopia.org>
Date: Thu, 7 Jun 2018 19:28:50 +0000 (+0200)
Subject: take care of revokers in verify path
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=b0a87a068a887f2cab43b6e48a94468804ee977c;p=oweals%2Fucert.git

take care of revokers in verify path

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
This work was sponsored by WIO (wiowireless.com)
---

diff --git a/ucert.c b/ucert.c
index 13975d1..8887a53 100644
--- a/ucert.c
+++ b/ucert.c
@@ -226,6 +226,7 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
 	struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
 	char tmpdir[] = "/tmp/ucert-XXXXXX";
 	char chainedpubkey[256] = {0};
+	char chainedfp[17] = {0};
 	char extsigfile[256] = {0};
 	int ret = 1;
 	int checkmsg = 0;
@@ -295,6 +296,19 @@ static int chain_verify(const char *msgfile, const char *pubkeyfile,
 				   blobmsg_data(payloadtb[CERT_PL_ATTR_PUBKEY]),
 				   blobmsg_data_len(payloadtb[CERT_PL_ATTR_PUBKEY]),
 				   false);
+
+			if (usign_f_pubkey(chainedfp, chainedpubkey)) {
+				if (!quiet)
+					fprintf(stderr, "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+					fprintf(stderr, "key %s has been revoked!\n", chainedfp);
+				ret = 4;
+				goto clean_and_return;
+			}
 		} else {
 		/* blob doesn't have payload, verify message using signature */
 			if (msgfile) {
@@ -500,9 +514,9 @@ 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");
-				return 2;
-			}
+			fprintf(stderr, "missing mandatory ucert attributes\n");
+			return 2;
+		}
 
 		certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
 		validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
@@ -521,10 +535,7 @@ static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
 		snprintf(rfname, sizeof(rfname)-1, "%s/%s", pubkeydir, fingerprint);
 		/* check if entry in pubkeydir exists */
 		if (stat(rfname, &st) == 0) {
-			char tml[64] = {0};
-			/* if it's an existing revoker deadlink we are happy */
-			if (readlink(rfname, tml, sizeof(tml)) > 0 &&
-			    !strcmp(tml, ".revoked.")) {
+			if (_usign_key_is_revoked(fingerprint, pubkeydir)) {
 				if (!quiet)
 					fprintf(stdout, "existing revoker deadlink for key %s\n", fingerprint);
 				continue;
diff --git a/usign-exec.c b/usign-exec.c
index 9112988..d88f750 100644
--- a/usign-exec.c
+++ b/usign-exec.c
@@ -1,59 +1,11 @@
 #include <stdbool.h>
+#include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/wait.h>
 
 #include "usign.h"
 
-int usign_v(const char *msgfile, const char *pubkeyfile,
-	    const char *pubkeydir, const char *sigfile, bool quiet) {
-	pid_t pid;
-	int status;
-	const char *usign_argv[16] = {0};
-	unsigned int usign_argc = 0;
-
-	usign_argv[usign_argc++] = "/usr/bin/usign";
-	usign_argv[usign_argc++] = "-V";
-	usign_argv[usign_argc++] = "-m";
-	usign_argv[usign_argc++] = msgfile;
-
-	if (quiet)
-		usign_argv[usign_argc++] = "-q";
-
-	if (pubkeyfile) {
-		usign_argv[usign_argc++] = "-p";
-		usign_argv[usign_argc++] = pubkeyfile;
-	}
-
-	if (pubkeydir) {
-		usign_argv[usign_argc++] = "-P";
-		usign_argv[usign_argc++] = pubkeydir;
-	}
-
-	if (sigfile) {
-		usign_argv[usign_argc++] = "-x";
-		usign_argv[usign_argc++] = sigfile;
-	}
-
-	pid = fork();
-	switch (pid) {
-	case -1:
-		return -1;
-
-	case 0:
-		if (execv(usign_argv[0], usign_argv))
-			return -1;
-
-		break;
-
-	default:
-		waitpid(pid, &status, 0);
-		return WEXITSTATUS(status);
-	}
-
-	return -1;
-}
-
 int usign_s(const char *msgfile, const char *seckeyfile, const char *sigfile, bool quiet) {
 	pid_t pid;
 	int status;
@@ -163,3 +115,72 @@ int usign_f_seckey(char *fingerprint, const char *seckeyfile) {
 int usign_f_sig(char *fingerprint, const char *sigfile) {
 	return usign_f(fingerprint, NULL, NULL, sigfile);
 }
+
+int _usign_key_is_revoked(const char *fingerprint, const char *pubkeydir) {
+	char tml[64] = {0};
+	char rfname[256] = {0};
+
+	snprintf(rfname, sizeof(rfname)-1, "%s/%s", pubkeydir, fingerprint);
+	if (readlink(rfname, tml, sizeof(tml)) > 0 &&
+	    !strcmp(tml, ".revoked.")) {
+		return true;
+	};
+
+	return false;
+}
+
+int usign_v(const char *msgfile, const char *pubkeyfile,
+	    const char *pubkeydir, const char *sigfile, bool quiet) {
+	pid_t pid;
+	int status;
+	const char *usign_argv[16] = {0};
+	unsigned int usign_argc = 0;
+	char fingerprint[17];
+
+	if (usign_f_sig(fingerprint, sigfile))
+		return 1;
+
+	if (pubkeydir && _usign_key_is_revoked(fingerprint, pubkeydir))
+		return 1;
+
+	usign_argv[usign_argc++] = "/usr/bin/usign";
+	usign_argv[usign_argc++] = "-V";
+	usign_argv[usign_argc++] = "-m";
+	usign_argv[usign_argc++] = msgfile;
+
+	if (quiet)
+		usign_argv[usign_argc++] = "-q";
+
+	if (pubkeyfile) {
+		usign_argv[usign_argc++] = "-p";
+		usign_argv[usign_argc++] = pubkeyfile;
+	}
+
+	if (pubkeydir) {
+		usign_argv[usign_argc++] = "-P";
+		usign_argv[usign_argc++] = pubkeydir;
+	}
+
+	if (sigfile) {
+		usign_argv[usign_argc++] = "-x";
+		usign_argv[usign_argc++] = sigfile;
+	}
+
+	pid = fork();
+	switch (pid) {
+	case -1:
+		return -1;
+
+	case 0:
+		if (execv(usign_argv[0], usign_argv))
+			return -1;
+
+		break;
+
+	default:
+		waitpid(pid, &status, 0);
+		return WEXITSTATUS(status);
+	}
+
+	return -1;
+}
diff --git a/usign.h b/usign.h
index e2f8e21..de52f17 100644
--- a/usign.h
+++ b/usign.h
@@ -8,3 +8,5 @@ int usign_f_pubkey(char *fingerprint, const char *pubkeyfile);
 int usign_f_seckey(char *fingerprint, const char *seckeyfile);
 
 int usign_f_sig(char *fingerprint, const char *sigfile);
+
+int _usign_key_is_revoked(const char *fingerprint, const char *pubkeydir);