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mac80211: allow drivers to control software crypto

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Some drivers unfortunately cannot support software crypto, but
mac80211 currently assumes that they do.

This has the issue that if the hardware enabling fails for some
reason, the software fallback is used, which won't work. This
clearly isn't desirable, the error should be reported and the
key setting refused.

Support this in mac80211 by allowing drivers to set a new HW
flag IEEE80211_HW_SW_CRYPTO_CONTROL, in which case mac80211 will
only allow software fallback if the set_key() method returns 1.
The driver will also need to advertise supported cipher suites
so that mac80211 doesn't advertise any (future) software ciphers
that the driver can't actually do.

While at it, to make it easier to support this, refactor the
ieee80211_init_cipher_suites() code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg
2015-01-22 18:44:19 +01:00
parent 54330bf63b
commit fa7e1fbcb5
3 changed files with 58 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
net/mac80211/main.c
View File

@@ -658,7 +658,6 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local)
bool have_wep = !(IS_ERR(local->wep_tx_tfm) ||
IS_ERR(local->wep_rx_tfm));
bool have_mfp = local->hw.flags & IEEE80211_HW_MFP_CAPABLE;
const struct ieee80211_cipher_scheme *cs = local->hw.cipher_schemes;
int n_suites = 0, r = 0, w = 0;
u32 *suites;
static const u32 cipher_suites[] = {
@@ -672,12 +671,38 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local)
WLAN_CIPHER_SUITE_AES_CMAC
};
/* Driver specifies the ciphers, we have nothing to do... */
if (local->hw.wiphy->cipher_suites && have_wep)
return 0;
if (local->hw.flags & IEEE80211_HW_SW_CRYPTO_CONTROL ||
local->hw.wiphy->cipher_suites) {
/* If the driver advertises, or doesn't support SW crypto,
* we only need to remove WEP if necessary.
*/
if (have_wep)
return 0;
/* Set up cipher suites if driver relies on mac80211 cipher defs */
if (!local->hw.wiphy->cipher_suites && !cs) {
/* well if it has _no_ ciphers ... fine */
if (!local->hw.wiphy->n_cipher_suites)
return 0;
/* Driver provides cipher suites, but we need to exclude WEP */
suites = kmemdup(local->hw.wiphy->cipher_suites,
sizeof(u32) * local->hw.wiphy->n_cipher_suites,
GFP_KERNEL);
if (!suites)
return -ENOMEM;
for (r = 0; r < local->hw.wiphy->n_cipher_suites; r++) {
u32 suite = local->hw.wiphy->cipher_suites[r];
if (suite == WLAN_CIPHER_SUITE_WEP40 ||
suite == WLAN_CIPHER_SUITE_WEP104)
continue;
suites[w++] = suite;
}
} else if (!local->hw.cipher_schemes) {
/* If the driver doesn't have cipher schemes, there's nothing
* else to do other than assign the (software supported and
* perhaps offloaded) cipher suites.
*/
local->hw.wiphy->cipher_suites = cipher_suites;
local->hw.wiphy->n_cipher_suites = ARRAY_SIZE(cipher_suites);
@@ -689,12 +714,16 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local)
local->hw.wiphy->n_cipher_suites -= 2;
}
/* not dynamically allocated, so just return */
return 0;
}
} else {
const struct ieee80211_cipher_scheme *cs;
if (!local->hw.wiphy->cipher_suites) {
/*
* Driver specifies cipher schemes only
cs = local->hw.cipher_schemes;
/* Driver specifies cipher schemes only (but not cipher suites
* including the schemes)
*
* We start counting ciphers defined by schemes, TKIP and CCMP
*/
n_suites = local->hw.n_cipher_schemes + 2;
@@ -724,22 +753,6 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local)
for (r = 0; r < local->hw.n_cipher_schemes; r++)
suites[w++] = cs[r].cipher;
} else {
/* Driver provides cipher suites, but we need to exclude WEP */
suites = kmemdup(local->hw.wiphy->cipher_suites,
sizeof(u32) * local->hw.wiphy->n_cipher_suites,
GFP_KERNEL);
if (!suites)
return -ENOMEM;
for (r = 0; r < local->hw.wiphy->n_cipher_suites; r++) {
u32 suite = local->hw.wiphy->cipher_suites[r];
if (suite == WLAN_CIPHER_SUITE_WEP40 ||
suite == WLAN_CIPHER_SUITE_WEP104)
continue;
suites[w++] = suite;
}
}
local->hw.wiphy->cipher_suites = suites;