dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted

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 <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 89 insertions, 0 deletions

diff --git a/crypto/sm3.c b/crypto/sm3.c
new file mode 100644
index 000000000..05111a99b
--- /dev/null
+++ b/crypto/sm3.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SM3 secure hash, as specified by OSCCA GM/T 0004-2012 SM3 and
+ * described at https://tools.ietf.org/html/draft-shen-sm3-hash-01
+ *
+ * Copyright (C) 2017 ARM Limited or its affiliates.
+ * Written by Gilad Ben-Yossef <gilad@benyossef.com>
+ * Copyright (C) 2021 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
+ * Copyright 2026 Google LLC
+ */
+
+#include <crypto/internal/hash.h>
+#include <crypto/sm3.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#define SM3_CTX(desc) ((struct sm3_ctx *)shash_desc_ctx(desc))
+
+static int crypto_sm3_init(struct shash_desc *desc)
+{
+	sm3_init(SM3_CTX(desc));
+	return 0;
+}
+
+static int crypto_sm3_update(struct shash_desc *desc,
+			     const u8 *data, unsigned int len)
+{
+	sm3_update(SM3_CTX(desc), data, len);
+	return 0;
+}
+
+static int crypto_sm3_final(struct shash_desc *desc, u8 *out)
+{
+	sm3_final(SM3_CTX(desc), out);
+	return 0;
+}
+
+static int crypto_sm3_digest(struct shash_desc *desc,
+			     const u8 *data, unsigned int len, u8 *out)
+{
+	sm3(data, len, out);
+	return 0;
+}
+
+static int crypto_sm3_export_core(struct shash_desc *desc, void *out)
+{
+	memcpy(out, SM3_CTX(desc), sizeof(struct sm3_ctx));
+	return 0;
+}
+
+static int crypto_sm3_import_core(struct shash_desc *desc, const void *in)
+{
+	memcpy(SM3_CTX(desc), in, sizeof(struct sm3_ctx));
+	return 0;
+}
+
+static struct shash_alg sm3_alg = {
+	.base.cra_name		= "sm3",
+	.base.cra_driver_name	= "sm3-lib",
+	.base.cra_priority	= 300,
+	.base.cra_blocksize	= SM3_BLOCK_SIZE,
+	.base.cra_module	= THIS_MODULE,
+	.digestsize		= SM3_DIGEST_SIZE,
+	.init			= crypto_sm3_init,
+	.update			= crypto_sm3_update,
+	.final			= crypto_sm3_final,
+	.digest			= crypto_sm3_digest,
+	.export_core		= crypto_sm3_export_core,
+	.import_core		= crypto_sm3_import_core,
+	.descsize		= sizeof(struct sm3_ctx),
+};
+
+static int __init crypto_sm3_mod_init(void)
+{
+	return crypto_register_shash(&sm3_alg);
+}
+module_init(crypto_sm3_mod_init);
+
+static void __exit crypto_sm3_mod_exit(void)
+{
+	crypto_unregister_shash(&sm3_alg);
+}
+module_exit(crypto_sm3_mod_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Crypto API support for SM3");
+
+MODULE_ALIAS_CRYPTO("sm3");
+MODULE_ALIAS_CRYPTO("sm3-lib");