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, 168 insertions, 0 deletions

diff --git a/include/crypto/internal/aead.h b/include/crypto/internal/aead.h
new file mode 100644
index 000000000..28a95eb31
--- /dev/null
+++ b/include/crypto/internal/aead.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * AEAD: Authenticated Encryption with Associated Data
+ * 
+ * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#ifndef _CRYPTO_INTERNAL_AEAD_H
+#define _CRYPTO_INTERNAL_AEAD_H
+
+#include <crypto/aead.h>
+#include <crypto/algapi.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+struct rtattr;
+
+struct aead_instance {
+	void (*free)(struct aead_instance *inst);
+	union {
+		struct {
+			char head[offsetof(struct aead_alg, base)];
+			struct crypto_instance base;
+		} s;
+		struct aead_alg alg;
+	};
+};
+
+struct crypto_aead_spawn {
+	struct crypto_spawn base;
+};
+
+struct aead_queue {
+	struct crypto_queue base;
+};
+
+static inline void *crypto_aead_ctx(struct crypto_aead *tfm)
+{
+	return crypto_tfm_ctx(&tfm->base);
+}
+
+static inline void *crypto_aead_ctx_dma(struct crypto_aead *tfm)
+{
+	return crypto_tfm_ctx_dma(&tfm->base);
+}
+
+static inline struct crypto_instance *aead_crypto_instance(
+	struct aead_instance *inst)
+{
+	return container_of(&inst->alg.base, struct crypto_instance, alg);
+}
+
+static inline struct aead_instance *aead_instance(struct crypto_instance *inst)
+{
+	return container_of(&inst->alg, struct aead_instance, alg.base);
+}
+
+static inline struct aead_instance *aead_alg_instance(struct crypto_aead *aead)
+{
+	return aead_instance(crypto_tfm_alg_instance(&aead->base));
+}
+
+static inline void *aead_instance_ctx(struct aead_instance *inst)
+{
+	return crypto_instance_ctx(aead_crypto_instance(inst));
+}
+
+static inline void *aead_request_ctx(struct aead_request *req)
+{
+	return req->__ctx;
+}
+
+static inline void *aead_request_ctx_dma(struct aead_request *req)
+{
+	unsigned int align = crypto_dma_align();
+
+	if (align <= crypto_tfm_ctx_alignment())
+		align = 1;
+
+	return PTR_ALIGN(aead_request_ctx(req), align);
+}
+
+static inline void aead_request_complete(struct aead_request *req, int err)
+{
+	crypto_request_complete(&req->base, err);
+}
+
+static inline u32 aead_request_flags(struct aead_request *req)
+{
+	return req->base.flags;
+}
+
+static inline struct aead_request *aead_request_cast(
+	struct crypto_async_request *req)
+{
+	return container_of(req, struct aead_request, base);
+}
+
+int crypto_grab_aead(struct crypto_aead_spawn *spawn,
+		     struct crypto_instance *inst,
+		     const char *name, u32 type, u32 mask);
+
+static inline void crypto_drop_aead(struct crypto_aead_spawn *spawn)
+{
+	crypto_drop_spawn(&spawn->base);
+}
+
+static inline struct aead_alg *crypto_spawn_aead_alg(
+	struct crypto_aead_spawn *spawn)
+{
+	return container_of(spawn->base.alg, struct aead_alg, base);
+}
+
+static inline struct crypto_aead *crypto_spawn_aead(
+	struct crypto_aead_spawn *spawn)
+{
+	return crypto_spawn_tfm2(&spawn->base);
+}
+
+static inline void crypto_aead_set_reqsize(struct crypto_aead *aead,
+					   unsigned int reqsize)
+{
+	aead->reqsize = reqsize;
+}
+
+static inline void crypto_aead_set_reqsize_dma(struct crypto_aead *aead,
+					       unsigned int reqsize)
+{
+	reqsize += crypto_dma_align() & ~(crypto_tfm_ctx_alignment() - 1);
+	aead->reqsize = reqsize;
+}
+
+static inline void aead_init_queue(struct aead_queue *queue,
+				   unsigned int max_qlen)
+{
+	crypto_init_queue(&queue->base, max_qlen);
+}
+
+static inline unsigned int crypto_aead_alg_chunksize(struct aead_alg *alg)
+{
+	return alg->chunksize;
+}
+
+/**
+ * crypto_aead_chunksize() - obtain chunk size
+ * @tfm: cipher handle
+ *
+ * The block size is set to one for ciphers such as CCM.  However,
+ * you still need to provide incremental updates in multiples of
+ * the underlying block size as the IV does not have sub-block
+ * granularity.  This is known in this API as the chunk size.
+ *
+ * Return: chunk size in bytes
+ */
+static inline unsigned int crypto_aead_chunksize(struct crypto_aead *tfm)
+{
+	return crypto_aead_alg_chunksize(crypto_aead_alg(tfm));
+}
+
+int crypto_register_aead(struct aead_alg *alg);
+void crypto_unregister_aead(struct aead_alg *alg);
+int crypto_register_aeads(struct aead_alg *algs, int count);
+void crypto_unregister_aeads(struct aead_alg *algs, int count);
+int aead_register_instance(struct crypto_template *tmpl,
+			   struct aead_instance *inst);
+
+#endif	/* _CRYPTO_INTERNAL_AEAD_H */
+