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authorKees Cook <kees+treewide@kernel.org>2026-09-02 15:31:14 -0700
committerKees Cook <kees@kernel.org>2026-09-04 21:37:00 -0700
commit3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch)
treec65086f9bdcd48c6360fb7cb4598bca084da1f32 /include/crypto/aes-ctr.h
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treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'include/crypto/aes-ctr.h')
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diff --git a/include/crypto/aes-ctr.h b/include/crypto/aes-ctr.h
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+++ b/include/crypto/aes-ctr.h
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * AES-CTR and AES-XCTR stream ciphers
+ *
+ * Copyright 2026 Google LLC
+ */
+#ifndef _CRYPTO_AES_CTR_H
+#define _CRYPTO_AES_CTR_H
+
+#include <crypto/aes.h>
+
+/**
+ * aes_ctr() - AES-CTR en/decryption
+ * @dst: The destination buffer. Can be in-place or out-of-place. For other
+ * overlaps the behavior is unspecified.
+ * @src: The source data
+ * @len: Number of bytes to en/decrypt
+ * @ctr: The counter. It will be incremented by ceil(@len / AES_BLOCK_SIZE).
+ * @key: The key, already prepared using aes_preparekey() or aes_prepareenckey()
+ *
+ * This implements AES in counter mode with a 128-bit big endian counter.
+ *
+ * This exists only for use by the implementation of modes built on top of CTR
+ * (e.g., GCM and CCM) and some legacy protocols that use CTR mode directly.
+ * Callers are expected to know how to use CTR mode appropriately, including
+ * choosing (key, counter) pairs appropriately to avoid keystream reuse.
+ *
+ * This supports incremental en/decryption. The length of each non-final chunk
+ * must be a multiple of AES_BLOCK_SIZE, and the updated @ctr must be passed in
+ * each time.
+ *
+ * Context: Any context.
+ */
+void aes_ctr(u8 *dst, const u8 *src, size_t len,
+ u8 ctr[at_least AES_BLOCK_SIZE], aes_encrypt_arg key);
+
+/**
+ * aes_xctr() - AES-XCTR en/decryption
+ * @dst: The destination buffer. Can be in-place or out-of-place. For other
+ * overlaps the behavior is unspecified.
+ * @src: The source data
+ * @len: Number of bytes to en/decrypt
+ * @ctr: The block counter (in host endianness). For the first call, set it to
+ * 1. It will be incremented by ceil(@len / AES_BLOCK_SIZE).
+ * @iv: The initialization vector
+ * @key: The key, already prepared using aes_preparekey() or aes_prepareenckey()
+ *
+ * This implements AES in XOR Counter mode, as specified in the paper
+ * "Length-preserving encryption with HCTR2"
+ * (https://eprint.iacr.org/2021/1441.pdf).
+ *
+ * This exists only for use by the implementation of modes built on top of XCTR.
+ * Callers are expected to know how to use XCTR mode appropriately, including
+ * choosing (key, IV) pairs appropriately to avoid keystream reuse.
+ *
+ * This supports incremental en/decryption. The length of each non-final chunk
+ * must be a multiple of AES_BLOCK_SIZE, and the updated @ctr must be passed in
+ * each time.
+ *
+ * Context: Any context.
+ */
+void aes_xctr(u8 *dst, const u8 *src, size_t len, u64 *ctr,
+ const u8 iv[at_least AES_BLOCK_SIZE], aes_encrypt_arg key);
+
+#endif /* _CRYPTO_AES_CTR_H */