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Date: Mon, 17 Oct 2016 10:33:15 +0200
From: Johannes Berg <johannes@...solutions.net>
To: linux-wireless@...r.kernel.org
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
netdev@...r.kernel.org, herbert@...dor.apana.org.au,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH v4] mac80211: move extra crypto data off the stack
From: Johannes Berg <johannes.berg@...el.com>
As the stack can (on x86-64) now be virtually mapped rather than
using "normal" kernel memory, Sergey noticed mac80211 isn't using
the SG APIs correctly by putting on-stack buffers into SG tables.
This leads to kernel crashes.
Fix this by allocating the extra fields dynamically on the fly as
needed, using a kmem cache.
I used per-CPU memory in a previous iteration of this patch, but
Ard Biesheuvel pointed out that was also vmalloc'ed on some
architectures.
Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
---
net/mac80211/aes_cmac.c | 5 +-
net/mac80211/aes_cmac.h | 2 +
net/mac80211/aes_gmac.c | 9 ++-
net/mac80211/aes_gmac.h | 5 +-
net/mac80211/ieee80211_i.h | 7 ++
net/mac80211/main.c | 8 +++
net/mac80211/wpa.c | 173 ++++++++++++++++++++++++++++++++++++---------
7 files changed, 166 insertions(+), 43 deletions(-)
diff --git a/net/mac80211/aes_cmac.c b/net/mac80211/aes_cmac.c
index bdf0790d89cc..ebb8c2dc9928 100644
--- a/net/mac80211/aes_cmac.c
+++ b/net/mac80211/aes_cmac.c
@@ -20,7 +20,6 @@
#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
#define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
-#define AAD_LEN 20
static void gf_mulx(u8 *pad)
@@ -101,7 +100,7 @@ void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad,
memset(zero, 0, CMAC_TLEN);
addr[0] = aad;
- len[0] = AAD_LEN;
+ len[0] = CMAC_AAD_LEN;
addr[1] = data;
len[1] = data_len - CMAC_TLEN;
addr[2] = zero;
@@ -119,7 +118,7 @@ void ieee80211_aes_cmac_256(struct crypto_cipher *tfm, const u8 *aad,
memset(zero, 0, CMAC_TLEN_256);
addr[0] = aad;
- len[0] = AAD_LEN;
+ len[0] = CMAC_AAD_LEN;
addr[1] = data;
len[1] = data_len - CMAC_TLEN_256;
addr[2] = zero;
diff --git a/net/mac80211/aes_cmac.h b/net/mac80211/aes_cmac.h
index 3702041f44fd..6645f8963278 100644
--- a/net/mac80211/aes_cmac.h
+++ b/net/mac80211/aes_cmac.h
@@ -11,6 +11,8 @@
#include <linux/crypto.h>
+#define CMAC_AAD_LEN 20
+
struct crypto_cipher *ieee80211_aes_cmac_key_setup(const u8 key[],
size_t key_len);
void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad,
diff --git a/net/mac80211/aes_gmac.c b/net/mac80211/aes_gmac.c
index 6951af9715c0..86892e2e3c8c 100644
--- a/net/mac80211/aes_gmac.c
+++ b/net/mac80211/aes_gmac.c
@@ -19,13 +19,12 @@
#define GMAC_MIC_LEN 16
#define GMAC_NONCE_LEN 12
-#define AAD_LEN 20
int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
- const u8 *data, size_t data_len, u8 *mic)
+ const u8 *data, size_t data_len, u8 *mic, u8 *zero)
{
struct scatterlist sg[4];
- u8 zero[GMAC_MIC_LEN], iv[AES_BLOCK_SIZE];
+ u8 iv[AES_BLOCK_SIZE];
struct aead_request *aead_req;
if (data_len < GMAC_MIC_LEN)
@@ -37,7 +36,7 @@ int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
memset(zero, 0, GMAC_MIC_LEN);
sg_init_table(sg, 4);
- sg_set_buf(&sg[0], aad, AAD_LEN);
+ sg_set_buf(&sg[0], aad, GMAC_AAD_LEN);
sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN);
sg_set_buf(&sg[2], zero, GMAC_MIC_LEN);
sg_set_buf(&sg[3], mic, GMAC_MIC_LEN);
@@ -47,7 +46,7 @@ int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
iv[AES_BLOCK_SIZE - 1] = 0x01;
aead_request_set_crypt(aead_req, sg, sg, 0, iv);
- aead_request_set_ad(aead_req, AAD_LEN + data_len);
+ aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len);
crypto_aead_encrypt(aead_req);
aead_request_free(aead_req);
diff --git a/net/mac80211/aes_gmac.h b/net/mac80211/aes_gmac.h
index d328204d73a8..f06833c9095f 100644
--- a/net/mac80211/aes_gmac.h
+++ b/net/mac80211/aes_gmac.h
@@ -11,10 +11,13 @@
#include <linux/crypto.h>
+#define GMAC_MIC_LEN 16
+#define GMAC_AAD_LEN 20
+
struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[],
size_t key_len);
int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
- const u8 *data, size_t data_len, u8 *mic);
+ const u8 *data, size_t data_len, u8 *mic, u8 *zero);
void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm);
#endif /* AES_GMAC_H */
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 34c2add2c455..a63593f6b645 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1128,6 +1128,13 @@ enum mac80211_scan_state {
SCAN_ABORT,
};
+struct ieee80211_crypto_bufs {
+ u8 buf1[32];
+ u8 buf2[16];
+} ____cacheline_aligned_in_smp;
+
+extern struct kmem_cache *ieee80211_crypto_bufs_cache;
+
struct ieee80211_local {
/* embed the driver visible part.
* don't cast (use the static inlines below), but we keep
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 1075ac24c8c5..c6303a8a12d2 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -33,6 +33,8 @@
#include "led.h"
#include "debugfs.h"
+struct kmem_cache *ieee80211_crypto_bufs_cache;
+
void ieee80211_configure_filter(struct ieee80211_local *local)
{
u64 mc;
@@ -1234,6 +1236,10 @@ static int __init ieee80211_init(void)
BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, driver_data) +
IEEE80211_TX_INFO_DRIVER_DATA_SIZE > sizeof(skb->cb));
+ ieee80211_crypto_bufs_cache = KMEM_CACHE(ieee80211_crypto_bufs, 0);
+ if (!ieee80211_crypto_bufs_cache)
+ return -ENOMEM;
+
ret = rc80211_minstrel_init();
if (ret)
return ret;
@@ -1264,6 +1270,8 @@ static void __exit ieee80211_exit(void)
ieee80211_iface_exit();
+ kmem_cache_destroy(ieee80211_crypto_bufs_cache);
+
rcu_barrier();
}
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 2e366438f8ef..ee9105d57545 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -405,8 +405,6 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb,
u8 *pos;
u8 pn[6];
u64 pn64;
- u8 aad[2 * AES_BLOCK_SIZE];
- u8 b_0[AES_BLOCK_SIZE];
if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
@@ -456,13 +454,34 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb,
ccmp_pn2hdr(pos, pn, key->conf.keyidx);
/* hwaccel - with software CCMP header */
- if (info->control.hw_key)
- return 0;
+ if (unlikely(!info->control.hw_key)) {
+ struct ieee80211_crypto_bufs *bufs;
+ int err;
+ u8 *aad;
+ u8 *b_0;
+
+ bufs = kmem_cache_alloc(ieee80211_crypto_bufs_cache,
+ GFP_ATOMIC);
+ if (!bufs)
+ return -ENOMEM;
+
+ BUILD_BUG_ON(sizeof(bufs->buf1) < 2 * AES_BLOCK_SIZE);
+ BUILD_BUG_ON(sizeof(bufs->buf2) < AES_BLOCK_SIZE);
+
+ aad = bufs->buf1;
+ b_0 = bufs->buf2;
+
+ pos += IEEE80211_CCMP_HDR_LEN;
+ ccmp_special_blocks(skb, pn, b_0, aad);
+ err = ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad,
+ pos, len,
+ skb_put(skb, mic_len),
+ mic_len);
+ kmem_cache_free(ieee80211_crypto_bufs_cache, bufs);
+ return err;
+ }
- pos += IEEE80211_CCMP_HDR_LEN;
- ccmp_special_blocks(skb, pn, b_0, aad);
- return ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
- skb_put(skb, mic_len), mic_len);
+ return 0;
}
@@ -532,16 +551,33 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
}
if (!(status->flag & RX_FLAG_DECRYPTED)) {
- u8 aad[2 * AES_BLOCK_SIZE];
- u8 b_0[AES_BLOCK_SIZE];
+ struct ieee80211_crypto_bufs *bufs;
+ int err;
+ u8 *aad;
+ u8 *b_0;
+
+ bufs = kmem_cache_alloc(ieee80211_crypto_bufs_cache,
+ GFP_ATOMIC);
+ if (!bufs)
+ return -ENOMEM;
+
+ BUILD_BUG_ON(sizeof(bufs->buf1) < 2 * AES_BLOCK_SIZE);
+ BUILD_BUG_ON(sizeof(bufs->buf2) < AES_BLOCK_SIZE);
+
+ aad = bufs->buf1;
+ b_0 = bufs->buf2;
+
/* hardware didn't decrypt/verify MIC */
ccmp_special_blocks(skb, pn, b_0, aad);
- if (ieee80211_aes_ccm_decrypt(
+ err = ieee80211_aes_ccm_decrypt(
key->u.ccmp.tfm, b_0, aad,
skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
data_len,
- skb->data + skb->len - mic_len, mic_len))
+ skb->data + skb->len - mic_len, mic_len);
+ kmem_cache_free(ieee80211_crypto_bufs_cache, bufs);
+
+ if (err)
return RX_DROP_UNUSABLE;
}
@@ -637,8 +673,6 @@ static int gcmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
u8 *pos;
u8 pn[6];
u64 pn64;
- u8 aad[2 * AES_BLOCK_SIZE];
- u8 j_0[AES_BLOCK_SIZE];
if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
@@ -689,13 +723,34 @@ static int gcmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
gcmp_pn2hdr(pos, pn, key->conf.keyidx);
/* hwaccel - with software GCMP header */
- if (info->control.hw_key)
- return 0;
+ if (unlikely(!info->control.hw_key)) {
+ struct ieee80211_crypto_bufs *bufs;
+ int err;
+ u8 *aad;
+ u8 *j_0;
+ u8 *mic = skb_put(skb, IEEE80211_GCMP_MIC_LEN);
+
+ bufs = kmem_cache_alloc(ieee80211_crypto_bufs_cache,
+ GFP_ATOMIC);
+ if (!bufs)
+ return -ENOMEM;
+
+ BUILD_BUG_ON(sizeof(bufs->buf1) < 2 * AES_BLOCK_SIZE);
+ BUILD_BUG_ON(sizeof(bufs->buf2) < AES_BLOCK_SIZE);
+
+ aad = bufs->buf1;
+ j_0 = bufs->buf2;
+
+ pos += IEEE80211_GCMP_HDR_LEN;
+ gcmp_special_blocks(skb, pn, j_0, aad);
+ err = ieee80211_aes_gcm_encrypt(key->u.gcmp.tfm, j_0, aad,
+ pos, len, mic);
+ kmem_cache_free(ieee80211_crypto_bufs_cache, bufs);
+
+ return err;
+ }
- pos += IEEE80211_GCMP_HDR_LEN;
- gcmp_special_blocks(skb, pn, j_0, aad);
- return ieee80211_aes_gcm_encrypt(key->u.gcmp.tfm, j_0, aad, pos, len,
- skb_put(skb, IEEE80211_GCMP_MIC_LEN));
+ return 0;
}
ieee80211_tx_result
@@ -760,17 +815,34 @@ ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
}
if (!(status->flag & RX_FLAG_DECRYPTED)) {
- u8 aad[2 * AES_BLOCK_SIZE];
- u8 j_0[AES_BLOCK_SIZE];
+ struct ieee80211_crypto_bufs *bufs;
+ int err;
+ u8 *aad;
+ u8 *j_0;
+
+ bufs = kmem_cache_alloc(ieee80211_crypto_bufs_cache,
+ GFP_ATOMIC);
+ if (!bufs)
+ return -ENOMEM;
+
+ BUILD_BUG_ON(sizeof(bufs->buf1) < 2 * AES_BLOCK_SIZE);
+ BUILD_BUG_ON(sizeof(bufs->buf2) < AES_BLOCK_SIZE);
+
+ aad = bufs->buf1;
+ j_0 = bufs->buf2;
+
/* hardware didn't decrypt/verify MIC */
gcmp_special_blocks(skb, pn, j_0, aad);
- if (ieee80211_aes_gcm_decrypt(
+ err = ieee80211_aes_gcm_decrypt(
key->u.gcmp.tfm, j_0, aad,
skb->data + hdrlen + IEEE80211_GCMP_HDR_LEN,
data_len,
skb->data + skb->len -
- IEEE80211_GCMP_MIC_LEN))
+ IEEE80211_GCMP_MIC_LEN);
+ kmem_cache_free(ieee80211_crypto_bufs_cache, bufs);
+
+ if (err)
return RX_DROP_UNUSABLE;
}
@@ -1119,9 +1191,12 @@ ieee80211_crypto_aes_gmac_encrypt(struct ieee80211_tx_data *tx)
struct ieee80211_key *key = tx->key;
struct ieee80211_mmie_16 *mmie;
struct ieee80211_hdr *hdr;
- u8 aad[20];
u64 pn64;
u8 nonce[12];
+ struct ieee80211_crypto_bufs *bufs;
+ int err;
+ u8 *aad;
+ u8 *zero;
if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
return TX_DROP;
@@ -1136,6 +1211,16 @@ ieee80211_crypto_aes_gmac_encrypt(struct ieee80211_tx_data *tx)
if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
return TX_DROP;
+ bufs = kmem_cache_alloc(ieee80211_crypto_bufs_cache, GFP_ATOMIC);
+ if (!bufs)
+ return TX_DROP;
+
+ BUILD_BUG_ON(sizeof(bufs->buf1) < GMAC_AAD_LEN);
+ BUILD_BUG_ON(sizeof(bufs->buf2) < GMAC_MIC_LEN);
+
+ aad = bufs->buf1;
+ zero = bufs->buf2;
+
mmie = (struct ieee80211_mmie_16 *)skb_put(skb, sizeof(*mmie));
mmie->element_id = WLAN_EID_MMIE;
mmie->length = sizeof(*mmie) - 2;
@@ -1153,11 +1238,13 @@ ieee80211_crypto_aes_gmac_encrypt(struct ieee80211_tx_data *tx)
bip_ipn_swap(nonce + ETH_ALEN, mmie->sequence_number);
/* MIC = AES-GMAC(IGTK, AAD || Management Frame Body || MMIE, 128) */
- if (ieee80211_aes_gmac(key->u.aes_gmac.tfm, aad, nonce,
- skb->data + 24, skb->len - 24, mmie->mic) < 0)
- return TX_DROP;
+ err = ieee80211_aes_gmac(key->u.aes_gmac.tfm, aad, nonce,
+ skb->data + 24, skb->len - 24, mmie->mic,
+ zero);
- return TX_CONTINUE;
+ kmem_cache_free(ieee80211_crypto_bufs_cache, bufs);
+
+ return err < 0 ? TX_DROP : TX_CONTINUE;
}
ieee80211_rx_result
@@ -1167,7 +1254,7 @@ ieee80211_crypto_aes_gmac_decrypt(struct ieee80211_rx_data *rx)
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_key *key = rx->key;
struct ieee80211_mmie_16 *mmie;
- u8 aad[20], mic[16], ipn[6], nonce[12];
+ u8 mic[16], ipn[6], nonce[12];
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
if (!ieee80211_is_mgmt(hdr->frame_control))
@@ -1192,16 +1279,34 @@ ieee80211_crypto_aes_gmac_decrypt(struct ieee80211_rx_data *rx)
}
if (!(status->flag & RX_FLAG_DECRYPTED)) {
+ struct ieee80211_crypto_bufs *bufs;
+ int err;
+ u8 *aad;
+ u8 *zero;
+
+ bufs = kmem_cache_alloc(ieee80211_crypto_bufs_cache,
+ GFP_ATOMIC);
+ if (!bufs)
+ return RX_DROP_UNUSABLE;
+
+ BUILD_BUG_ON(sizeof(bufs->buf1) < GMAC_AAD_LEN);
+ BUILD_BUG_ON(sizeof(bufs->buf2) < GMAC_MIC_LEN);
+
+ aad = bufs->buf1;
+ zero = bufs->buf2;
+
/* hardware didn't decrypt/verify MIC */
bip_aad(skb, aad);
memcpy(nonce, hdr->addr2, ETH_ALEN);
memcpy(nonce + ETH_ALEN, ipn, 6);
- if (ieee80211_aes_gmac(key->u.aes_gmac.tfm, aad, nonce,
- skb->data + 24, skb->len - 24,
- mic) < 0 ||
- memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
+ err = ieee80211_aes_gmac(key->u.aes_gmac.tfm, aad, nonce,
+ skb->data + 24, skb->len - 24,
+ mic, zero);
+ kmem_cache_free(ieee80211_crypto_bufs_cache, bufs);
+
+ if (err < 0 || memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
key->u.aes_gmac.icverrors++;
return RX_DROP_UNUSABLE;
}
--
2.8.1
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