ipv6/send/patches/002-handle_max_bits_conf.patch

   1 This patch allows one to specify a maximum number of bits
   2 for the CGA and RSA key size. RFC specifies that an implementation
   3 may optionnaly honor this setting (5.1.3). This is particularly
   4 useful on embedded systems where both the entropy and the processing
   5 power are limited.
   6
   7 --- a/sendd/config.c
   8 +++ b/sendd/config.c
   9 @@ -82,6 +82,7 @@ struct snd_conf snd_confs[] = {
  10         SND_CFS(snd_cga_params, NULL, 1),
  11         SND_CFIB(snd_full_secure, 1, 0),
  12         SND_CFII(snd_min_key_bits, 1024, "bits", 0),
  13 +       SND_CFII(snd_max_key_bits, 2048, "bits", 0),
  14         SND_CFII(snd_nonce_cache_gc_intvl, 2, "seconds", 0),
  15         SND_CFII(snd_pfx_cache_gc_intvl, 40, "seconds", 0),
  16         SND_CFS(snd_pkixip_conf, NULL, 0),
  17 --- a/sendd/sig_rfc3971.c
  18 +++ b/sendd/sig_rfc3971.c
  19 @@ -147,7 +147,7 @@ ver(struct iovec *iov, int iovlen, uint8
  20         EVP_MD_CTX ctx[1];
  21         EVP_PKEY *pub;
  22         int rv = -1;
  23 -       int i, real_slen, min_bits;
  24 +       int i, real_slen, min_bits, max_bits;
  25         DEFINE_TIMESTAMP_VARS();
  26
  27         DBG_HEXDUMP(&dbg_cryptox, "key: ", key, klen);
  28 @@ -164,6 +164,12 @@ ver(struct iovec *iov, int iovlen, uint8
  29                     "minimum: %d)", EVP_PKEY_bits(pub), min_bits);
  30                 return (-1);
  31         }
  32 +       max_bits = snd_conf_get_int(snd_max_key_bits);
  33 +       if (EVP_PKEY_bits(pub) > max_bits) {
  34 +               DBG(&dbg_snd, "Peer key too strong: %d bits (configured "
  35 +                   "maximum: %d)", EVP_PKEY_bits(pub), max_bits);
  36 +               return (-1);
  37 +       }
  38
  39         real_slen = EVP_PKEY_size(pub);
  40         if (real_slen < slen) {
  41 --- a/sendd/snd_config.h
  42 +++ b/sendd/snd_config.h
  43 @@ -42,6 +42,7 @@ enum snd_conf_syms {
  44         snd_cga_params,
  45         snd_full_secure,
  46         snd_min_key_bits,
  47 +       snd_max_key_bits,
  48         snd_nonce_cache_gc_intvl,
  49         snd_pfx_cache_gc_intvl,
  50         snd_pkixip_conf,