crypto: cavium/nitrox - fix a DMA pool free failure

In crypto_alloc_context(), a DMA pool is allocated through dma_pool_alloc()
to hold the crypto context. The meta data of the DMA pool, including the
pool used for the allocation 'ndev->ctx_pool' and the base address of the
DMA pool used by the device 'dma', are then stored to the beginning of the
pool. These meta data are eventually used in crypto_free_context() to free
the DMA pool through dma_pool_free(). However, given that the DMA pool can
also be accessed by the device, a malicious device can modify these meta
data, especially when the device is controlled to deploy an attack. This
can cause an unexpected DMA pool free failure.

To avoid the above issue, this patch introduces a new structure
crypto_ctx_hdr and a new field chdr in the structure nitrox_crypto_ctx hold
the meta data information of the DMA pool after the allocation. Note that
the original structure ctx_hdr is not changed to ensure the compatibility.

Cc: <stable@vger.kernel.org>
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/crypto/cavium/nitrox/nitrox_req.h b/drivers/crypto/cavium/nitrox/nitrox_req.h
index d091b6f5f5dd..19f0a20e3bb3 100644
--- a/drivers/crypto/cavium/nitrox/nitrox_req.h
+++ b/drivers/crypto/cavium/nitrox/nitrox_req.h
@@ -181,12 +181,19 @@ struct flexi_crypto_context {
 	struct auth_keys auth;
 };
 
+struct crypto_ctx_hdr {
+	struct dma_pool *pool;
+	dma_addr_t dma;
+	void *vaddr;
+};
+
 struct nitrox_crypto_ctx {
 	struct nitrox_device *ndev;
 	union {
 		u64 ctx_handle;
 		struct flexi_crypto_context *fctx;
 	} u;
+	struct crypto_ctx_hdr *chdr;
 };
 
 struct nitrox_kcrypt_request {