x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 210 insertions, 0 deletions

diff --git a/include/crypto/md5.h b/include/crypto/md5.h
new file mode 100644
index 000000000..c47aedfe6
--- /dev/null
+++ b/include/crypto/md5.h
@@ -0,0 +1,210 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CRYPTO_MD5_H
+#define _CRYPTO_MD5_H
+
+#include <crypto/hash.h>
+#include <linux/types.h>
+
+#define MD5_DIGEST_SIZE		16
+#define MD5_HMAC_BLOCK_SIZE	64
+#define MD5_BLOCK_SIZE		64
+#define MD5_BLOCK_WORDS		16
+#define MD5_HASH_WORDS		4
+#define MD5_STATE_SIZE		24
+
+#define MD5_H0	0x67452301UL
+#define MD5_H1	0xefcdab89UL
+#define MD5_H2	0x98badcfeUL
+#define MD5_H3	0x10325476UL
+
+#define CRYPTO_MD5_STATESIZE \
+	CRYPTO_HASH_STATESIZE(MD5_STATE_SIZE, MD5_HMAC_BLOCK_SIZE)
+
+extern const u8 md5_zero_message_hash[MD5_DIGEST_SIZE];
+
+struct md5_state {
+	u32 hash[MD5_HASH_WORDS];
+	u64 byte_count;
+	u32 block[MD5_BLOCK_WORDS];
+};
+
+/* State for the MD5 compression function */
+struct md5_block_state {
+	u32 h[MD5_HASH_WORDS];
+};
+
+/**
+ * struct md5_ctx - Context for hashing a message with MD5
+ * @state: the compression function state
+ * @bytecount: number of bytes processed so far
+ * @buf: partial block buffer; bytecount % MD5_BLOCK_SIZE bytes are valid
+ */
+struct md5_ctx {
+	struct md5_block_state state;
+	u64 bytecount;
+	u8 buf[MD5_BLOCK_SIZE] __aligned(__alignof__(__le64));
+};
+
+/**
+ * md5_init() - Initialize an MD5 context for a new message
+ * @ctx: the context to initialize
+ *
+ * If you don't need incremental computation, consider md5() instead.
+ *
+ * Context: Any context.
+ */
+void md5_init(struct md5_ctx *ctx);
+
+/**
+ * md5_update() - Update an MD5 context with message data
+ * @ctx: the context to update; must have been initialized
+ * @data: the message data
+ * @len: the data length in bytes
+ *
+ * This can be called any number of times.
+ *
+ * Context: Any context.
+ */
+void md5_update(struct md5_ctx *ctx, const u8 *data, size_t len);
+
+/**
+ * md5_final() - Finish computing an MD5 message digest
+ * @ctx: the context to finalize; must have been initialized
+ * @out: (output) the resulting MD5 message digest
+ *
+ * After finishing, this zeroizes @ctx.  So the caller does not need to do it.
+ *
+ * Context: Any context.
+ */
+void md5_final(struct md5_ctx *ctx, u8 out[at_least MD5_DIGEST_SIZE]);
+
+/**
+ * md5() - Compute MD5 message digest in one shot
+ * @data: the message data
+ * @len: the data length in bytes
+ * @out: (output) the resulting MD5 message digest
+ *
+ * Context: Any context.
+ */
+void md5(const u8 *data, size_t len, u8 out[at_least MD5_DIGEST_SIZE]);
+
+/**
+ * struct hmac_md5_key - Prepared key for HMAC-MD5
+ * @istate: private
+ * @ostate: private
+ */
+struct hmac_md5_key {
+	struct md5_block_state istate;
+	struct md5_block_state ostate;
+};
+
+/**
+ * struct hmac_md5_ctx - Context for computing HMAC-MD5 of a message
+ * @hash_ctx: private
+ * @ostate: private
+ */
+struct hmac_md5_ctx {
+	struct md5_ctx hash_ctx;
+	struct md5_block_state ostate;
+};
+
+/**
+ * hmac_md5_preparekey() - Prepare a key for HMAC-MD5
+ * @key: (output) the key structure to initialize
+ * @raw_key: the raw HMAC-MD5 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ *
+ * Note: the caller is responsible for zeroizing both the struct hmac_md5_key
+ * and the raw key once they are no longer needed.
+ *
+ * Context: Any context.
+ */
+void hmac_md5_preparekey(struct hmac_md5_key *key,
+			 const u8 *raw_key, size_t raw_key_len);
+
+/**
+ * hmac_md5_init() - Initialize an HMAC-MD5 context for a new message
+ * @ctx: (output) the HMAC context to initialize
+ * @key: the prepared HMAC key
+ *
+ * If you don't need incremental computation, consider hmac_md5() instead.
+ *
+ * Context: Any context.
+ */
+void hmac_md5_init(struct hmac_md5_ctx *ctx, const struct hmac_md5_key *key);
+
+/**
+ * hmac_md5_init_usingrawkey() - Initialize an HMAC-MD5 context for a new
+ *				  message, using a raw key
+ * @ctx: (output) the HMAC context to initialize
+ * @raw_key: the raw HMAC-MD5 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ *
+ * If you don't need incremental computation, consider hmac_md5_usingrawkey()
+ * instead.
+ *
+ * Context: Any context.
+ */
+void hmac_md5_init_usingrawkey(struct hmac_md5_ctx *ctx,
+			       const u8 *raw_key, size_t raw_key_len);
+
+/**
+ * hmac_md5_update() - Update an HMAC-MD5 context with message data
+ * @ctx: the HMAC context to update; must have been initialized
+ * @data: the message data
+ * @data_len: the data length in bytes
+ *
+ * This can be called any number of times.
+ *
+ * Context: Any context.
+ */
+static inline void hmac_md5_update(struct hmac_md5_ctx *ctx,
+				   const u8 *data, size_t data_len)
+{
+	md5_update(&ctx->hash_ctx, data, data_len);
+}
+
+/**
+ * hmac_md5_final() - Finish computing an HMAC-MD5 value
+ * @ctx: the HMAC context to finalize; must have been initialized
+ * @out: (output) the resulting HMAC-MD5 value
+ *
+ * After finishing, this zeroizes @ctx.  So the caller does not need to do it.
+ *
+ * Context: Any context.
+ */
+void hmac_md5_final(struct hmac_md5_ctx *ctx, u8 out[at_least MD5_DIGEST_SIZE]);
+
+/**
+ * hmac_md5() - Compute HMAC-MD5 in one shot, using a prepared key
+ * @key: the prepared HMAC key
+ * @data: the message data
+ * @data_len: the data length in bytes
+ * @out: (output) the resulting HMAC-MD5 value
+ *
+ * If you're using the key only once, consider using hmac_md5_usingrawkey().
+ *
+ * Context: Any context.
+ */
+void hmac_md5(const struct hmac_md5_key *key,
+	      const u8 *data, size_t data_len,
+	      u8 out[at_least MD5_DIGEST_SIZE]);
+
+/**
+ * hmac_md5_usingrawkey() - Compute HMAC-MD5 in one shot, using a raw key
+ * @raw_key: the raw HMAC-MD5 key
+ * @raw_key_len: the key length in bytes.  All key lengths are supported.
+ * @data: the message data
+ * @data_len: the data length in bytes
+ * @out: (output) the resulting HMAC-MD5 value
+ *
+ * If you're using the key multiple times, prefer to use hmac_md5_preparekey()
+ * followed by multiple calls to hmac_md5() instead.
+ *
+ * Context: Any context.
+ */
+void hmac_md5_usingrawkey(const u8 *raw_key, size_t raw_key_len,
+			  const u8 *data, size_t data_len,
+			  u8 out[at_least MD5_DIGEST_SIZE]);
+
+#endif /* _CRYPTO_MD5_H */