client: Fix a memory leak in client_post_select().

[paraslash.git] / crypt.c

diff --git a/crypt.c b/crypt.c
index 679ba35dd07d59ec184942524f8a1bb0be786939..49e9e8ae7863fed3f40881a356957f115bf31769 100644 (file)
--- a/crypt.c
+++ b/crypt.c
@@ -6,6 +6,7 @@
 
 /** \file crypt.c openssl-based RSA encryption/decryption routines */
 
+#include <regex.h>
 #include <dirent.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -64,11 +65,29 @@ void init_random_seed_or_die(void)
        srandom(seed);
 }
 
+static int check_key_file(const char *file, int private)
+{
+       struct stat st;
+
+       if (stat(file, &st) != 0)
+               return -ERRNO_TO_PARA_ERROR(errno);
+       if (private != LOAD_PRIVATE_KEY)
+               return 0;
+       if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0)
+               return -E_KEY_PERM;
+       return 1;
+}
+
 static EVP_PKEY *load_key(const char *file, int private)
 {
        BIO *key;
        EVP_PKEY *pkey = NULL;
+       int ret = check_key_file(file, private);
 
+       if (ret < 0) {
+               PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+               return NULL;
+       }
        key = BIO_new(BIO_s_file());
        if (!key)
                return NULL;
@@ -145,35 +164,19 @@ int para_decrypt_buffer(char *key_file, unsigned char *outbuf, unsigned char *in
        ret = get_rsa_key(key_file, &rsa, LOAD_PRIVATE_KEY);
        if (ret < 0)
                return ret;
-       ret = RSA_private_decrypt(inlen, inbuf, outbuf, rsa, RSA_PKCS1_PADDING);
+       /*
+        * RSA is vulnerable to timing attacks. Generate a random blinding
+        * factor to protect against this kind of attack.
+        */
+       ret = -E_BLINDING;
+       if (RSA_blinding_on(rsa, NULL) == 0)
+               goto out;
+       ret = RSA_private_decrypt(inlen, inbuf, outbuf, rsa, RSA_PKCS1_OAEP_PADDING);
+       RSA_blinding_off(rsa);
+       if (ret <= 0)
+               ret = -E_DECRYPT;
+out:
        rsa_free(rsa);
-       return (ret > 0)? ret : -E_DECRYPT;
-}
-
-/**
- * decrypt the challenge number sent by para_server
- *
- * \param key_file full path of the rsa key
- * \param challenge_nr result is stored here
- * \param inbuf the input buffer
- * \param rsa_inlen the length of \a inbuf
- *
- * \return positive on success, negative on errors
- *
- * \sa para_decrypt_buffer()
- */
-int para_decrypt_challenge(char *key_file, long unsigned *challenge_nr,
-               unsigned char *inbuf, unsigned rsa_inlen)
-{
-       unsigned char *rsa_out = OPENSSL_malloc(rsa_inlen + 1);
-       int ret = para_decrypt_buffer(key_file, rsa_out, inbuf, rsa_inlen);
-
-       if (ret >= 0) {
-               rsa_out[ret] = '\0';
-               ret = sscanf((char *)rsa_out, "%lu", challenge_nr) == 1?
-                       1 : -E_CHALLENGE;
-       }
-       OPENSSL_free(rsa_out);
        return ret;
 }
 
@@ -196,31 +199,8 @@ int para_encrypt_buffer(RSA *rsa, unsigned char *inbuf,
 
        if (flen < 0)
                return -E_ENCRYPT;
-       ret = RSA_public_encrypt(flen, inbuf, outbuf, rsa, RSA_PKCS1_PADDING);
-       return ret < 0?  -E_ENCRYPT : ret;
-}
-
-/**
- * encrypt the given challenge number
- *
- * \param rsa: public rsa key
- * \param challenge_nr the number to be encrypted
- * \param outbuf the output buffer
- *
- * \a outbuf must be at least 64 bytes long
- *
- * \return The size of the encrypted data on success, negative on errors
- *
- * \sa para_encrypt_buffer()
- *
- */
-int para_encrypt_challenge(RSA* rsa, long unsigned challenge_nr,
-       unsigned char *outbuf)
-{
-       unsigned char *inbuf = (unsigned char*) make_message("%lu", challenge_nr);
-       int ret = para_encrypt_buffer(rsa, inbuf, strlen((char *)inbuf), outbuf);
-       free(inbuf);
-       return ret;
+       ret = RSA_public_encrypt(flen, inbuf, outbuf, rsa, RSA_PKCS1_OAEP_PADDING);
+       return ret < 0? -E_ENCRYPT : ret;
 }
 
 /**