From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- lib/crypto/aescfb.c | 237 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 237 insertions(+) create mode 100644 lib/crypto/aescfb.c (limited to 'lib/crypto/aescfb.c') diff --git a/lib/crypto/aescfb.c b/lib/crypto/aescfb.c new file mode 100644 index 000000000..82cd55436 --- /dev/null +++ b/lib/crypto/aescfb.c @@ -0,0 +1,237 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Minimal library implementation of AES in CFB mode + * + * Copyright 2023 Google LLC + */ + +#include +#include +#include +#include + +/** + * aescfb_encrypt - Perform AES-CFB encryption on a block of data + * + * @key: The AES-CFB key schedule + * @dst: Pointer to the ciphertext output buffer + * @src: Pointer the plaintext (may equal @dst for encryption in place) + * @len: The size in bytes of the plaintext and ciphertext. + * @iv: The initialization vector (IV) to use for this block of data + */ +void aescfb_encrypt(const struct aes_enckey *key, u8 *dst, const u8 *src, + int len, const u8 iv[AES_BLOCK_SIZE]) +{ + u8 ks[AES_BLOCK_SIZE]; + const u8 *v = iv; + + while (len > 0) { + aes_encrypt(key, ks, v); + crypto_xor_cpy(dst, src, ks, min(len, AES_BLOCK_SIZE)); + v = dst; + + dst += AES_BLOCK_SIZE; + src += AES_BLOCK_SIZE; + len -= AES_BLOCK_SIZE; + } + + memzero_explicit(ks, sizeof(ks)); +} +EXPORT_SYMBOL(aescfb_encrypt); + +/** + * aescfb_decrypt - Perform AES-CFB decryption on a block of data + * + * @key: The AES-CFB key schedule + * @dst: Pointer to the plaintext output buffer + * @src: Pointer the ciphertext (may equal @dst for decryption in place) + * @len: The size in bytes of the plaintext and ciphertext. + * @iv: The initialization vector (IV) to use for this block of data + */ +void aescfb_decrypt(const struct aes_enckey *key, u8 *dst, const u8 *src, + int len, const u8 iv[AES_BLOCK_SIZE]) +{ + u8 ks[2][AES_BLOCK_SIZE]; + + aes_encrypt(key, ks[0], iv); + + for (int i = 0; len > 0; i ^= 1) { + if (len > AES_BLOCK_SIZE) + /* + * Generate the keystream for the next block before + * performing the XOR, as that may update in place and + * overwrite the ciphertext. + */ + aes_encrypt(key, ks[!i], src); + + crypto_xor_cpy(dst, src, ks[i], min(len, AES_BLOCK_SIZE)); + + dst += AES_BLOCK_SIZE; + src += AES_BLOCK_SIZE; + len -= AES_BLOCK_SIZE; + } + + memzero_explicit(ks, sizeof(ks)); +} +EXPORT_SYMBOL(aescfb_decrypt); + +MODULE_DESCRIPTION("Generic AES-CFB library"); +MODULE_AUTHOR("Ard Biesheuvel "); +MODULE_LICENSE("GPL"); + +#ifdef CONFIG_CRYPTO_SELFTESTS + +/* + * Test code below. Vectors taken from crypto/testmgr.h + */ + +static struct { + u8 ptext[64] __nonstring; + u8 ctext[64] __nonstring; + + u8 key[AES_MAX_KEY_SIZE] __nonstring; + u8 iv[AES_BLOCK_SIZE] __nonstring; + + int klen; + int len; +} const aescfb_tv[] __initconst = { + { /* From NIST SP800-38A */ + .key = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6" + "\xab\xf7\x15\x88\x09\xcf\x4f\x3c", + .klen = 16, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96" + "\xe9\x3d\x7e\x11\x73\x93\x17\x2a" + "\xae\x2d\x8a\x57\x1e\x03\xac\x9c" + "\x9e\xb7\x6f\xac\x45\xaf\x8e\x51" + "\x30\xc8\x1c\x46\xa3\x5c\xe4\x11" + "\xe5\xfb\xc1\x19\x1a\x0a\x52\xef" + "\xf6\x9f\x24\x45\xdf\x4f\x9b\x17" + "\xad\x2b\x41\x7b\xe6\x6c\x37\x10", + .ctext = "\x3b\x3f\xd9\x2e\xb7\x2d\xad\x20" + "\x33\x34\x49\xf8\xe8\x3c\xfb\x4a" + "\xc8\xa6\x45\x37\xa0\xb3\xa9\x3f" + "\xcd\xe3\xcd\xad\x9f\x1c\xe5\x8b" + "\x26\x75\x1f\x67\xa3\xcb\xb1\x40" + "\xb1\x80\x8c\xf1\x87\xa4\xf4\xdf" + "\xc0\x4b\x05\x35\x7c\x5d\x1c\x0e" + "\xea\xc4\xc6\x6f\x9f\xf7\xf2\xe6", + .len = 64, + }, { + .key = "\x8e\x73\xb0\xf7\xda\x0e\x64\x52" + "\xc8\x10\xf3\x2b\x80\x90\x79\xe5" + "\x62\xf8\xea\xd2\x52\x2c\x6b\x7b", + .klen = 24, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96" + "\xe9\x3d\x7e\x11\x73\x93\x17\x2a" + "\xae\x2d\x8a\x57\x1e\x03\xac\x9c" + "\x9e\xb7\x6f\xac\x45\xaf\x8e\x51" + "\x30\xc8\x1c\x46\xa3\x5c\xe4\x11" + "\xe5\xfb\xc1\x19\x1a\x0a\x52\xef" + "\xf6\x9f\x24\x45\xdf\x4f\x9b\x17" + "\xad\x2b\x41\x7b\xe6\x6c\x37\x10", + .ctext = "\xcd\xc8\x0d\x6f\xdd\xf1\x8c\xab" + "\x34\xc2\x59\x09\xc9\x9a\x41\x74" + "\x67\xce\x7f\x7f\x81\x17\x36\x21" + "\x96\x1a\x2b\x70\x17\x1d\x3d\x7a" + "\x2e\x1e\x8a\x1d\xd5\x9b\x88\xb1" + "\xc8\xe6\x0f\xed\x1e\xfa\xc4\xc9" + "\xc0\x5f\x9f\x9c\xa9\x83\x4f\xa0" + "\x42\xae\x8f\xba\x58\x4b\x09\xff", + .len = 64, + }, { + .key = "\x60\x3d\xeb\x10\x15\xca\x71\xbe" + "\x2b\x73\xae\xf0\x85\x7d\x77\x81" + "\x1f\x35\x2c\x07\x3b\x61\x08\xd7" + "\x2d\x98\x10\xa3\x09\x14\xdf\xf4", + .klen = 32, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96" + "\xe9\x3d\x7e\x11\x73\x93\x17\x2a" + "\xae\x2d\x8a\x57\x1e\x03\xac\x9c" + "\x9e\xb7\x6f\xac\x45\xaf\x8e\x51" + "\x30\xc8\x1c\x46\xa3\x5c\xe4\x11" + "\xe5\xfb\xc1\x19\x1a\x0a\x52\xef" + "\xf6\x9f\x24\x45\xdf\x4f\x9b\x17" + "\xad\x2b\x41\x7b\xe6\x6c\x37\x10", + .ctext = "\xdc\x7e\x84\xbf\xda\x79\x16\x4b" + "\x7e\xcd\x84\x86\x98\x5d\x38\x60" + "\x39\xff\xed\x14\x3b\x28\xb1\xc8" + "\x32\x11\x3c\x63\x31\xe5\x40\x7b" + "\xdf\x10\x13\x24\x15\xe5\x4b\x92" + "\xa1\x3e\xd0\xa8\x26\x7a\xe2\xf9" + "\x75\xa3\x85\x74\x1a\xb9\xce\xf8" + "\x20\x31\x62\x3d\x55\xb1\xe4\x71", + .len = 64, + }, { /* > 16 bytes, not a multiple of 16 bytes */ + .key = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6" + "\xab\xf7\x15\x88\x09\xcf\x4f\x3c", + .klen = 16, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96" + "\xe9\x3d\x7e\x11\x73\x93\x17\x2a" + "\xae", + .ctext = "\x3b\x3f\xd9\x2e\xb7\x2d\xad\x20" + "\x33\x34\x49\xf8\xe8\x3c\xfb\x4a" + "\xc8", + .len = 17, + }, { /* < 16 bytes */ + .key = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6" + "\xab\xf7\x15\x88\x09\xcf\x4f\x3c", + .klen = 16, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f", + .ctext = "\x3b\x3f\xd9\x2e\xb7\x2d\xad", + .len = 7, + }, +}; + +static int __init libaescfb_init(void) +{ + for (int i = 0; i < ARRAY_SIZE(aescfb_tv); i++) { + struct aes_enckey key; + u8 buf[64]; + + if (aes_prepareenckey(&key, aescfb_tv[i].key, aescfb_tv[i].klen)) { + pr_err("aes_prepareenckey() failed on vector %d\n", i); + return -ENODEV; + } + + aescfb_encrypt(&key, buf, aescfb_tv[i].ptext, aescfb_tv[i].len, + aescfb_tv[i].iv); + if (memcmp(buf, aescfb_tv[i].ctext, aescfb_tv[i].len)) { + pr_err("aescfb_encrypt() #1 failed on vector %d\n", i); + return -ENODEV; + } + + /* decrypt in place */ + aescfb_decrypt(&key, buf, buf, aescfb_tv[i].len, aescfb_tv[i].iv); + if (memcmp(buf, aescfb_tv[i].ptext, aescfb_tv[i].len)) { + pr_err("aescfb_decrypt() failed on vector %d\n", i); + return -ENODEV; + } + + /* encrypt in place */ + aescfb_encrypt(&key, buf, buf, aescfb_tv[i].len, aescfb_tv[i].iv); + if (memcmp(buf, aescfb_tv[i].ctext, aescfb_tv[i].len)) { + pr_err("aescfb_encrypt() #2 failed on vector %d\n", i); + + return -ENODEV; + } + + } + return 0; +} +module_init(libaescfb_init); + +static void __exit libaescfb_exit(void) +{ +} +module_exit(libaescfb_exit); +#endif -- cgit v1.3.1