From: Kuan-Wei Chiu Date: Fri, 14 Nov 2025 06:00:45 +0000 (+0800) Subject: lib/base64: add support for multiple variants X-Git-Tag: v6.19-rc1~70^2~71 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f1e2ca801c54dfc09d6a5540207cec25e8d43f6f;p=thirdparty%2Fkernel%2Flinux.git lib/base64: add support for multiple variants Patch series " lib/base64: add generic encoder/decoder, migrate users", v5. This series introduces a generic Base64 encoder/decoder to the kernel library, eliminating duplicated implementations and delivering significant performance improvements. The Base64 API has been extended to support multiple variants (Standard, URL-safe, and IMAP) as defined in RFC 4648 and RFC 3501. The API now takes a variant parameter and an option to control padding. As part of this series, users are migrated to the new interface while preserving their specific formats: fscrypt now uses BASE64_URLSAFE, Ceph uses BASE64_IMAP, and NVMe is updated to BASE64_STD. On the encoder side, the implementation processes input in 3-byte blocks, mapping 24 bits directly to 4 output symbols. This avoids bit-by-bit streaming and reduces loop overhead, achieving about a 2.7x speedup compared to previous implementations. On the decoder side, replace strchr() lookups with per-variant reverse tables and process input in 4-character groups. Each group is mapped to numeric values and combined into 3 bytes. Padded and unpadded forms are validated explicitly, rejecting invalid '=' usage and enforcing tail rules. This improves throughput by ~43-52x. This patch (of 6): Extend the base64 API to support multiple variants (standard, URL-safe, and IMAP) as defined in RFC 4648 and RFC 3501. The API now takes a variant parameter and an option to control padding. Update NVMe auth code to use the new interface with BASE64_STD. Link: https://lkml.kernel.org/r/20251114055829.87814-1-409411716@gms.tku.edu.tw Link: https://lkml.kernel.org/r/20251114060045.88792-1-409411716@gms.tku.edu.tw Signed-off-by: Kuan-Wei Chiu Co-developed-by: Guan-Chun Wu <409411716@gms.tku.edu.tw> Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw> Reviewed-by: David Laight Cc: Christoph Hellwig Cc: Eric Biggers Cc: Ilya Dryomov Cc: Jaegeuk Kim Cc: Jens Axboe Cc: Keith Busch Cc: Sagi Grimberg Cc: "Theodore Y. Ts'o" Cc: Viacheslav Dubeyko Cc: Xiubo Li Cc: Yu-Sheng Huang Signed-off-by: Andrew Morton --- diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c index 1f51fbebd9fac..e07e7d4bf8b68 100644 --- a/drivers/nvme/common/auth.c +++ b/drivers/nvme/common/auth.c @@ -178,7 +178,7 @@ struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret, if (!key) return ERR_PTR(-ENOMEM); - key_len = base64_decode(secret, allocated_len, key->key); + key_len = base64_decode(secret, allocated_len, key->key, true, BASE64_STD); if (key_len < 0) { pr_debug("base64 key decoding error %d\n", key_len); @@ -663,7 +663,7 @@ int nvme_auth_generate_digest(u8 hmac_id, u8 *psk, size_t psk_len, if (ret) goto out_free_digest; - ret = base64_encode(digest, digest_len, enc); + ret = base64_encode(digest, digest_len, enc, true, BASE64_STD); if (ret < hmac_len) { ret = -ENOKEY; goto out_free_digest; diff --git a/include/linux/base64.h b/include/linux/base64.h index 660d4cb1ef31f..a2c6c9222da36 100644 --- a/include/linux/base64.h +++ b/include/linux/base64.h @@ -8,9 +8,15 @@ #include +enum base64_variant { + BASE64_STD, /* RFC 4648 (standard) */ + BASE64_URLSAFE, /* RFC 4648 (base64url) */ + BASE64_IMAP, /* RFC 3501 */ +}; + #define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3) -int base64_encode(const u8 *src, int len, char *dst); -int base64_decode(const char *src, int len, u8 *dst); +int base64_encode(const u8 *src, int len, char *dst, bool padding, enum base64_variant variant); +int base64_decode(const char *src, int len, u8 *dst, bool padding, enum base64_variant variant); #endif /* _LINUX_BASE64_H */ diff --git a/lib/base64.c b/lib/base64.c index b736a7a431c50..a7c20a8e8e987 100644 --- a/lib/base64.c +++ b/lib/base64.c @@ -1,12 +1,12 @@ // SPDX-License-Identifier: GPL-2.0 /* - * base64.c - RFC4648-compliant base64 encoding + * base64.c - Base64 with support for multiple variants * * Copyright (c) 2020 Hannes Reinecke, SUSE * * Based on the base64url routines from fs/crypto/fname.c - * (which are using the URL-safe base64 encoding), - * modified to use the standard coding table from RFC4648 section 4. + * (which are using the URL-safe Base64 encoding), + * modified to support multiple Base64 variants. */ #include @@ -15,26 +15,31 @@ #include #include -static const char base64_table[65] = - "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +static const char base64_tables[][65] = { + [BASE64_STD] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/", + [BASE64_URLSAFE] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_", + [BASE64_IMAP] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,", +}; /** - * base64_encode() - base64-encode some binary data + * base64_encode() - Base64-encode some binary data * @src: the binary data to encode * @srclen: the length of @src in bytes - * @dst: (output) the base64-encoded string. Not NUL-terminated. + * @dst: (output) the Base64-encoded string. Not NUL-terminated. + * @padding: whether to append '=' padding characters + * @variant: which base64 variant to use * - * Encodes data using base64 encoding, i.e. the "Base 64 Encoding" specified - * by RFC 4648, including the '='-padding. + * Encodes data using the selected Base64 variant. * - * Return: the length of the resulting base64-encoded string in bytes. + * Return: the length of the resulting Base64-encoded string in bytes. */ -int base64_encode(const u8 *src, int srclen, char *dst) +int base64_encode(const u8 *src, int srclen, char *dst, bool padding, enum base64_variant variant) { u32 ac = 0; int bits = 0; int i; char *cp = dst; + const char *base64_table = base64_tables[variant]; for (i = 0; i < srclen; i++) { ac = (ac << 8) | src[i]; @@ -48,44 +53,49 @@ int base64_encode(const u8 *src, int srclen, char *dst) *cp++ = base64_table[(ac << (6 - bits)) & 0x3f]; bits -= 6; } - while (bits < 0) { - *cp++ = '='; - bits += 2; + if (padding) { + while (bits < 0) { + *cp++ = '='; + bits += 2; + } } return cp - dst; } EXPORT_SYMBOL_GPL(base64_encode); /** - * base64_decode() - base64-decode a string + * base64_decode() - Base64-decode a string * @src: the string to decode. Doesn't need to be NUL-terminated. * @srclen: the length of @src in bytes * @dst: (output) the decoded binary data + * @padding: whether to append '=' padding characters + * @variant: which base64 variant to use * - * Decodes a string using base64 encoding, i.e. the "Base 64 Encoding" - * specified by RFC 4648, including the '='-padding. + * Decodes a string using the selected Base64 variant. * * This implementation hasn't been optimized for performance. * * Return: the length of the resulting decoded binary data in bytes, - * or -1 if the string isn't a valid base64 string. + * or -1 if the string isn't a valid Base64 string. */ -int base64_decode(const char *src, int srclen, u8 *dst) +int base64_decode(const char *src, int srclen, u8 *dst, bool padding, enum base64_variant variant) { u32 ac = 0; int bits = 0; int i; u8 *bp = dst; + const char *base64_table = base64_tables[variant]; for (i = 0; i < srclen; i++) { const char *p = strchr(base64_table, src[i]); - - if (src[i] == '=') { - ac = (ac << 6); - bits += 6; - if (bits >= 8) - bits -= 8; - continue; + if (padding) { + if (src[i] == '=') { + ac = (ac << 6); + bits += 6; + if (bits >= 8) + bits -= 8; + continue; + } } if (p == NULL || src[i] == 0) return -1;