Opkg support for smime (pkcs7) packages list signing

Thanks to Camille Moncelier <moncelier@devlife.org>
http://groups.google.com/group/opkg-devel/browse_thread/thread/6071ce290d5ceb77?utoken=qjR-TC0AAADKDldt5ZXsDDLs9sWCpWZI1zgeariQUwksg5ob1tmaFTCAL7MTcQRO6S85GfHgQ_k

As promised :) here is a patch allowing opkg to authenticate
a package list using smime and openssl instead of gpgme

Example:

 Sign a package list:
openssl smime -sign -in /path/to/repo/Packages \
       -signer /root/server.pem -binary \
       -outform PEM -out /path/to/repo/Packages.sig

 Configuration in /etc/opkg/opkg.conf
option check_signature 1
option signature_ca_file /etc/serverCA.pem
 option signature_ca_path /path/to/certs/dir

 opkg update
Downloading http://repo:8000/Packages
Updated list of available packages in /usr/lib/opkg/lists/angstrom
Downloading http://repo:8000/Packages.sig
Signature check passed

 Package list corruption or MIM:
Downloading http://repo:8000/Packages
Updated list of available packages in /usr/lib/opkg/lists/angstrom
Downloading http://repo:8000/Packages.sig
Signature check failed
Collected errors:
 * Verification failure

Camille Moncelier
http://devlife.org/

git-svn-id: http://opkg.googlecode.com/svn/trunk@221 e8e0d7a0-c8d9-11dd-a880-a1081c7ac358

1 files changed, 140 insertions, 2 deletions

diff --git a/libopkg/opkg_download.c b/libopkg/opkg_download.c
index f185f22..e31c49c 100644
--- a/libopkg/opkg_download.c
+++ b/libopkg/opkg_download.c
@@ -20,8 +20,17 @@
 #ifdef HAVE_CURL
 #include <curl/curl.h>
 #endif
-#ifdef HAVE_GPGME
+#if defined(HAVE_GPGME)
 #include <gpgme.h>
+#elif defined(HAVE_OPENSSL)
+#include <openssl/bio.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/objects.h>
+#include <openssl/x509.h>
+#include <openssl/pem.h>
+#include <openssl/hmac.h>
+
 #endif
 
 #include "includes.h"
@@ -35,6 +44,12 @@
 #include "str_util.h"
 #include "opkg_defines.h"
 
+
+#ifdef HAVE_OPENSSL
+static X509_STORE *setup_verify(opkg_conf_t *conf, char *CAfile, char *CApath);
+static void init_openssl(void);
+#endif
+
 int opkg_download(opkg_conf_t *conf, const char *src,
   const char *dest_file_name, curl_progress_func cb, void *data)
 {
@@ -307,7 +322,7 @@ int opkg_prepare_url_for_install(opkg_conf_t *conf, const char *url, char **name
 int
 opkg_verify_file (opkg_conf_t *conf, char *text_file, char *sig_file)
 {
-#ifdef HAVE_GPGME
+#if defined HAVE_GPGME
     if (conf->check_signature == 0 )
         return 0;
     int status = -1;
@@ -375,7 +390,130 @@ opkg_verify_file (opkg_conf_t *conf, char *text_file, char *sig_file)
     gpgme_release (ctx);
 
     return status;
+#elif defined HAVE_OPENSSL
+    X509_STORE *store = NULL;
+    PKCS7 *p7 = NULL;
+    BIO *in = NULL, *indata = NULL;
+
+    // Sig check failed by default !
+    int status = -1;
+
+    init_openssl();
+
+    // Set-up the key store
+    if(!(store = setup_verify(conf, conf->signature_ca_file, conf->signature_ca_path))){
+        opkg_message(conf, OPKG_ERROR,
+                "Can't open CA certificates\n");
+        goto verify_file_end;
+    }
+
+    // Open a BIO to read the sig file
+    if (!(in = BIO_new_file(sig_file, "rb"))){
+        opkg_message(conf, OPKG_ERROR,
+                "Can't open signature file %s\n", sig_file);
+        goto verify_file_end;
+    }
+
+    // Read the PKCS7 block contained in the sig file
+    p7 = PEM_read_bio_PKCS7(in, NULL, NULL, NULL);
+    if(!p7){
+        opkg_message(conf, OPKG_ERROR,
+                "Can't read signature file (Corrupted ?)\n");
+        goto verify_file_end;
+    }
+
+    // Open the Package file to authenticate
+    if (!(indata = BIO_new_file(text_file, "rb"))){
+        opkg_message(conf, OPKG_ERROR,
+                "Can't open file %s\n", text_file);
+        goto verify_file_end;
+    }
+
+    // Let's verify the autenticity !
+    if (PKCS7_verify(p7, NULL, store, indata, NULL, PKCS7_BINARY) != 1){
+        // Get Off My Lawn!
+        opkg_message(conf, OPKG_ERROR,
+                "Verification failure\n");
+    }else{
+        // Victory !
+        status = 0;
+    }
+
+verify_file_end:
+    BIO_free(in);
+    BIO_free(indata);
+    PKCS7_free(p7);
+    X509_STORE_free(store);
+
+    return status;
 #else
     return 0;
 #endif
 }
+
+
+#if defined HAVE_OPENSSL
+static X509_STORE *setup_verify(opkg_conf_t *conf, char *CAfile, char *CApath){
+    X509_STORE *store = NULL;
+    X509_LOOKUP *lookup = NULL;
+
+    if(!(store = X509_STORE_new())){
+        // Something bad is happening...
+        goto end;
+    }
+
+    // adds the X509 file lookup method
+    lookup = X509_STORE_add_lookup(store,X509_LOOKUP_file());
+    if (lookup == NULL){
+        goto end;
+    }
+
+    // Autenticating against one CA file
+    if (CAfile) {
+        if(!X509_LOOKUP_load_file(lookup,CAfile,X509_FILETYPE_PEM)) {
+            // Invalid CA => Bye bye
+            opkg_message(conf, OPKG_ERROR,
+                    "Error loading file %s\n", CAfile);
+            goto end;
+        }
+    } else {
+        X509_LOOKUP_load_file(lookup,NULL,X509_FILETYPE_DEFAULT);
+    }
+
+    // Now look into CApath directory if supplied
+    lookup = X509_STORE_add_lookup(store,X509_LOOKUP_hash_dir());
+    if (lookup == NULL){
+        goto end;
+    }
+
+    if (CApath) {
+        if(!X509_LOOKUP_add_dir(lookup,CApath,X509_FILETYPE_PEM)) {
+            opkg_message(conf, OPKG_ERROR,
+                    "Error loading directory %s\n", CApath);
+            goto end;
+        }
+    } else {
+        X509_LOOKUP_add_dir(lookup,NULL,X509_FILETYPE_DEFAULT);
+    }
+
+    // All right !
+    ERR_clear_error();
+    return store;
+
+end:
+
+    X509_STORE_free(store);
+    return NULL;
+
+}
+
+static void init_openssl(void){
+    static int init = 0;
+
+    if(!init){      
+        OpenSSL_add_all_algorithms();       
+        ERR_load_crypto_strings();
+        init = 1;
+    }
+}
+#endif