| Message ID | 20211201004858.19831-18-nstange@suse.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | crypto: dh - infrastructure for NVM in-band auth and FIPS conformance | expand |
On 12/1/21 1:48 AM, Nicolai Stange wrote: > A subsequent patch will make the DH implementation to reject any input > domain parameter set with ->group_id == dh_group_id_unknown in FIPS mode. > However, as the keyctl(KEYCTL_DH_COMPUTE) implementation simply passes > forward keys from userspace, it does not (and cannot) set ->group_id to > anything else than dh_group_id_unknown. > > In order to still allow for keyctl(KEYCTL_DH_COMPUTE) to work on approved > domain parameters passed in from userspace in FIPS mode, make > crypto_dh_decode_key() to compare them against any of the known groups and > set ->group_id upon having found a match, if any. > > Signed-off-by: Nicolai Stange <nstange@suse.de> > --- > crypto/dh_helper.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
diff --git a/crypto/dh_helper.c b/crypto/dh_helper.c index 5a8c9c50297f..cf632beca65e 100644 --- a/crypto/dh_helper.c +++ b/crypto/dh_helper.c @@ -471,6 +471,36 @@ get_safe_prime_group(enum dh_group_id group_id) return NULL; } +static enum dh_group_id lookup_group_id(const char *g, size_t g_size, + const char *p, size_t p_size) +{ + int i; + + /* All safe-prime groups use a generator of g == 2. */ + while (g_size && !*g) { + ++g; + --g_size; + } + + if (g_size != 1 || *g != 2) + return dh_group_id_unknown; + + while (p_size && !*p) { + ++p; + --p_size; + } + + for (i = 0; i < ARRAY_SIZE(safe_prime_groups); ++i) { + if (safe_prime_groups[i].p_size != p_size) + continue; + + if (!memcmp(safe_prime_groups[i].p, p, p_size)) + return safe_prime_groups[i].group_id; + } + + return dh_group_id_unknown; +} + static inline u8 *dh_pack_data(u8 *dst, u8 *end, const void *src, size_t size) { if (!dst || size > end - dst) @@ -566,6 +596,9 @@ int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params) if (memchr_inv(params->p, 0, params->p_size) == NULL) return -EINVAL; + params->group_id = lookup_group_id(params->g, params->g_size, + params->p, params->p_size); + } else { const struct safe_prime_group *g;
A subsequent patch will make the DH implementation to reject any input domain parameter set with ->group_id == dh_group_id_unknown in FIPS mode. However, as the keyctl(KEYCTL_DH_COMPUTE) implementation simply passes forward keys from userspace, it does not (and cannot) set ->group_id to anything else than dh_group_id_unknown. In order to still allow for keyctl(KEYCTL_DH_COMPUTE) to work on approved domain parameters passed in from userspace in FIPS mode, make crypto_dh_decode_key() to compare them against any of the known groups and set ->group_id upon having found a match, if any. Signed-off-by: Nicolai Stange <nstange@suse.de> --- crypto/dh_helper.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)