Generate RSA Key Pair for Push Notifications.

Signed-off-by: Ivan Sein <ivan@nextcloud.com>

VideoCalls/NCSettingsController.h

@@ -16,6 +16,8 @@ extern NSString * const kNCUserKey;
 extern NSString * const kNCUserDisplayNameKey;
 extern NSString * const kNCTokenKey;
 extern NSString * const kNCPushTokenKey;
+extern NSString * const kNCPNPublicKey;
+extern NSString * const kNCPNPrivateKey;
 
 
 @interface NCSettingsController : NSObject
@@ -25,6 +27,8 @@ extern NSString * const kNCPushTokenKey;
 @property (nonatomic, copy) NSString *ncUserDisplayName;
 @property (nonatomic, copy) NSString *ncToken;
 @property (nonatomic, copy) NSString *ncPushToken;
+@property (nonatomic, copy) NSData *ncPNPublicKey;
+@property (nonatomic, copy) NSData *ncPNPrivateKey;
 
 + (instancetype)sharedInstance;
 - (void)cleanAllStoredValues;

VideoCalls/NCSettingsController.m

@@ -8,6 +8,11 @@
 
 #import "NCSettingsController.h"
 
+#import <openssl/rsa.h>
+#import <openssl/pem.h>
+#import <openssl/bio.h>
+#import <openssl/bn.h>
+
 #import "NCAPIController.h"
 
 @implementation NCSettingsController
@@ -17,6 +22,8 @@ NSString * const kNCUserKey             = @"ncUser";
 NSString * const kNCUserDisplayNameKey  = @"ncUserDisplayName";
 NSString * const kNCTokenKey            = @"ncToken";
 NSString * const kNCPushTokenKey        = @"ncPushToken";
+NSString * const kNCPNPublicKey         = @"ncPNPublicKey";
+NSString * const kNCPNPrivateKey        = @"ncPNPrivateKey";
 
 + (NCSettingsController *)sharedInstance
 {
@@ -44,6 +51,12 @@ NSString * const kNCPushTokenKey        = @"ncPushToken";
     _ncUserDisplayName = [UICKeyChainStore stringForKey:kNCUserDisplayNameKey];
     _ncToken = [UICKeyChainStore stringForKey:kNCTokenKey];
     _ncPushToken = [UICKeyChainStore stringForKey:kNCPushTokenKey];
+    _ncPNPublicKey = [UICKeyChainStore dataForKey:kNCPNPublicKey];
+    _ncPNPrivateKey = [UICKeyChainStore dataForKey:kNCPNPrivateKey];
+    
+    if (!_ncPNPublicKey) {
+        [self generatePushNotificationsKeyPair];
+    }
 }
 
 - (void)cleanAllStoredValues
@@ -53,6 +66,8 @@ NSString * const kNCPushTokenKey        = @"ncPushToken";
     _ncUserDisplayName = nil;
     _ncToken = nil;
     _ncPushToken = nil;
+    _ncPNPublicKey = nil;
+    _ncPNPrivateKey = nil;
     
     [UICKeyChainStore removeAllItems];
     
@@ -60,4 +75,75 @@ NSString * const kNCPushTokenKey        = @"ncPushToken";
     [[NCAPIController sharedInstance] setAuthHeaderWithUser:NULL andToken:NULL];
 }
 
+- (BOOL)generatePushNotificationsKeyPair
+{
+    EVP_PKEY *pkey;
+    NSError *keyError;
+    pkey = [self generateRSAKey:&keyError];
+    if (keyError) {
+        return NO;
+    }
+    
+    // Extract publicKey, privateKey
+    int len;
+    char *keyBytes;
+    
+    // PublicKey
+    BIO *publicKeyBIO = BIO_new(BIO_s_mem());
+    PEM_write_bio_PUBKEY(publicKeyBIO, pkey);
+    
+    len = BIO_pending(publicKeyBIO);
+    keyBytes  = malloc(len);
+    
+    BIO_read(publicKeyBIO, keyBytes, len);
+    _ncPNPublicKey = [NSData dataWithBytes:keyBytes length:len];
+    [UICKeyChainStore setData:_ncPNPublicKey forKey:kNCPNPublicKey];
+    NSLog(@"Push Notifications Key Pair generated: \n%@", [[NSString alloc] initWithData:_ncPNPublicKey encoding:NSUTF8StringEncoding]);
+    
+    // PrivateKey
+    BIO *privateKeyBIO = BIO_new(BIO_s_mem());
+    PEM_write_bio_PKCS8PrivateKey(privateKeyBIO, pkey, NULL, NULL, 0, NULL, NULL);
+    
+    len = BIO_pending(privateKeyBIO);
+    keyBytes = malloc(len);
+    
+    BIO_read(privateKeyBIO, keyBytes, len);
+    _ncPNPrivateKey = [NSData dataWithBytes:keyBytes length:len];
+    [UICKeyChainStore setData:_ncPNPrivateKey forKey:kNCPNPrivateKey];
+    
+    EVP_PKEY_free(pkey);
+    
+    return YES;
+}
+
+- (EVP_PKEY *)generateRSAKey:(NSError **)error
+{
+    EVP_PKEY *pkey = EVP_PKEY_new();
+    if (!pkey) {
+        return NULL;
+    }
+    
+    BIGNUM *bigNumber = BN_new();
+    int exponent = RSA_F4;
+    RSA *rsa = RSA_new();
+    
+    if (BN_set_word(bigNumber, exponent) < 0) {
+        goto cleanup;
+    }
+    
+    if (RSA_generate_key_ex(rsa, 2048, bigNumber, NULL) < 0) {
+        goto cleanup;
+    }
+    
+    if (!EVP_PKEY_set1_RSA(pkey, rsa)) {
+        goto cleanup;
+    }
+    
+cleanup:
+    RSA_free(rsa);
+    BN_free(bigNumber);
+    
+    return pkey;
+}
+
 @end