openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 94 insertions, 0 deletions

diff --git a/net/mac80211/aes_gmac.c b/net/mac80211/aes_gmac.c
new file mode 100644
index 000000000..811a83d8d
--- /dev/null
+++ b/net/mac80211/aes_gmac.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256
+ * Copyright 2015, Qualcomm Atheros, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/err.h>
+#include <crypto/aead.h>
+#include <crypto/aes.h>
+
+#include <net/mac80211.h>
+#include "key.h"
+#include "aes_gmac.h"
+
+int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
+		       const u8 *data, size_t data_len, u8 *mic)
+{
+	struct scatterlist sg[5];
+	u8 *zero, *__aad, iv[AES_BLOCK_SIZE];
+	struct aead_request *aead_req;
+	int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
+	const __le16 *fc;
+	int ret;
+
+	if (data_len < IEEE80211_GMAC_MIC_LEN)
+		return -EINVAL;
+
+	aead_req = kzalloc(reqsize + IEEE80211_GMAC_MIC_LEN + GMAC_AAD_LEN,
+			   GFP_ATOMIC);
+	if (!aead_req)
+		return -ENOMEM;
+
+	zero = (u8 *)aead_req + reqsize;
+	__aad = zero + IEEE80211_GMAC_MIC_LEN;
+	memcpy(__aad, aad, GMAC_AAD_LEN);
+
+	fc = (const __le16 *)aad;
+	if (ieee80211_is_beacon(*fc)) {
+		/* mask Timestamp field to zero */
+		sg_init_table(sg, 5);
+		sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
+		sg_set_buf(&sg[1], zero, 8);
+		sg_set_buf(&sg[2], data + 8,
+			   data_len - 8 - IEEE80211_GMAC_MIC_LEN);
+		sg_set_buf(&sg[3], zero, IEEE80211_GMAC_MIC_LEN);
+		sg_set_buf(&sg[4], mic, IEEE80211_GMAC_MIC_LEN);
+	} else {
+		sg_init_table(sg, 4);
+		sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
+		sg_set_buf(&sg[1], data, data_len - IEEE80211_GMAC_MIC_LEN);
+		sg_set_buf(&sg[2], zero, IEEE80211_GMAC_MIC_LEN);
+		sg_set_buf(&sg[3], mic, IEEE80211_GMAC_MIC_LEN);
+	}
+
+	memcpy(iv, nonce, GMAC_NONCE_LEN);
+	memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN);
+	iv[AES_BLOCK_SIZE - 1] = 0x01;
+
+	aead_request_set_tfm(aead_req, tfm);
+	aead_request_set_crypt(aead_req, sg, sg, 0, iv);
+	aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len);
+
+	ret = crypto_aead_encrypt(aead_req);
+	kfree_sensitive(aead_req);
+
+	return ret;
+}
+
+struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[],
+						 size_t key_len)
+{
+	struct crypto_aead *tfm;
+	int err;
+
+	tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(tfm))
+		return tfm;
+
+	err = crypto_aead_setkey(tfm, key, key_len);
+	if (!err)
+		err = crypto_aead_setauthsize(tfm, IEEE80211_GMAC_MIC_LEN);
+	if (!err)
+		return tfm;
+
+	crypto_free_aead(tfm);
+	return ERR_PTR(err);
+}
+
+void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm)
+{
+	crypto_free_aead(tfm);
+}