From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- include/crypto/dh.h | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 include/crypto/dh.h (limited to 'include/crypto/dh.h') diff --git a/include/crypto/dh.h b/include/crypto/dh.h new file mode 100644 index 000000000..7b863e911 --- /dev/null +++ b/include/crypto/dh.h @@ -0,0 +1,98 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Diffie-Hellman secret to be used with kpp API along with helper functions + * + * Copyright (c) 2016, Intel Corporation + * Authors: Salvatore Benedetto + */ +#ifndef _CRYPTO_DH_ +#define _CRYPTO_DH_ + +/** + * DOC: DH Helper Functions + * + * To use DH with the KPP cipher API, the following data structure and + * functions should be used. + * + * To use DH with KPP, the following functions should be used to operate on + * a DH private key. The packet private key that can be set with + * the KPP API function call of crypto_kpp_set_secret. + */ + +/** + * struct dh - define a DH private key + * + * @key: Private DH key + * @p: Diffie-Hellman parameter P + * @g: Diffie-Hellman generator G + * @key_size: Size of the private DH key + * @p_size: Size of DH parameter P + * @g_size: Size of DH generator G + */ +struct dh { + const void *key; + const void *p; + const void *g; + unsigned int key_size; + unsigned int p_size; + unsigned int g_size; +}; + +/** + * crypto_dh_key_len() - Obtain the size of the private DH key + * @params: private DH key + * + * This function returns the packet DH key size. A caller can use that + * with the provided DH private key reference to obtain the required + * memory size to hold a packet key. + * + * Return: size of the key in bytes + */ +unsigned int crypto_dh_key_len(const struct dh *params); + +/** + * crypto_dh_encode_key() - encode the private key + * @buf: Buffer allocated by the caller to hold the packet DH + * private key. The buffer should be at least crypto_dh_key_len + * bytes in size. + * @len: Length of the packet private key buffer + * @params: Buffer with the caller-specified private key + * + * The DH implementations operate on a packet representation of the private + * key. + * + * Return: -EINVAL if buffer has insufficient size, 0 on success + */ +int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params); + +/** + * crypto_dh_decode_key() - decode a private key + * @buf: Buffer holding a packet key that should be decoded + * @len: Length of the packet private key buffer + * @params: Buffer allocated by the caller that is filled with the + * unpacked DH private key. + * + * The unpacking obtains the private key by pointing @p to the correct location + * in @buf. Thus, both pointers refer to the same memory. + * + * Return: -EINVAL if buffer has insufficient size, 0 on success + */ +int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params); + +/** + * __crypto_dh_decode_key() - decode a private key without parameter checks + * @buf: Buffer holding a packet key that should be decoded + * @len: Length of the packet private key buffer + * @params: Buffer allocated by the caller that is filled with the + * unpacked DH private key. + * + * Internal function providing the same services as the exported + * crypto_dh_decode_key(), but without any of those basic parameter + * checks conducted by the latter. + * + * Return: -EINVAL if buffer has insufficient size, 0 on success + */ +int __crypto_dh_decode_key(const char *buf, unsigned int len, + struct dh *params); + +#endif -- cgit v1.3.1