* + lib-base64-add-support-for-multiple-variants.patch added to mm-nonmm-unstable branch
@ 2025-11-01 4:10 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-11-01 4:10 UTC (permalink / raw)
To: mm-commits, xiubli, tytso, sagi, kbusch, jaegeuk, idryomov,
home7438072, hch, ebiggers, axboe, 409411716, visitorckw, akpm
The patch titled
Subject: lib/base64: add support for multiple variants
has been added to the -mm mm-nonmm-unstable branch. Its filename is
lib-base64-add-support-for-multiple-variants.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-base64-add-support-for-multiple-variants.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kuan-Wei Chiu <visitorckw@gmail.com>
Subject: lib/base64: add support for multiple variants
Date: Wed, 29 Oct 2025 18:20:12 +0800
Patch series "lib/base64: add generic encoder/decoder, migrate users", v4.
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/20251029102012.542970-1-409411716@gms.tku.edu.tw
Link: https://lore.kernel.org/lkml/20250926065235.13623-1-409411716@gms.tku.edu.tw/
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Co-developed-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/nvme/common/auth.c | 4 +-
include/linux/base64.h | 10 ++++-
lib/base64.c | 62 ++++++++++++++++++++---------------
3 files changed, 46 insertions(+), 30 deletions(-)
--- a/drivers/nvme/common/auth.c~lib-base64-add-support-for-multiple-variants
+++ a/drivers/nvme/common/auth.c
@@ -178,7 +178,7 @@ struct nvme_dhchap_key *nvme_auth_extrac
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
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;
--- a/include/linux/base64.h~lib-base64-add-support-for-multiple-variants
+++ a/include/linux/base64.h
@@ -8,9 +8,15 @@
#include <linux/types.h>
+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 */
--- a/lib/base64.c~lib-base64-add-support-for-multiple-variants
+++ a/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 <linux/kernel.h>
@@ -15,26 +15,31 @@
#include <linux/string.h>
#include <linux/base64.h>
-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 src
*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;
_
Patches currently in -mm which might be from visitorckw@gmail.com are
lib-base64-add-support-for-multiple-variants.patch
lib-base64-optimize-base64_decode-with-reverse-lookup-tables.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* + lib-base64-add-support-for-multiple-variants.patch added to mm-nonmm-unstable branch
@ 2025-11-14 22:58 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-11-14 22:58 UTC (permalink / raw)
To: mm-commits, xiubli, tytso, Slava.Dubeyko, sagi, kbusch, jaegeuk,
idryomov, home7438072, hch, ebiggers, david.laight.linux, axboe,
409411716, visitorckw, akpm
The patch titled
Subject: lib/base64: add support for multiple variants
has been added to the -mm mm-nonmm-unstable branch. Its filename is
lib-base64-add-support-for-multiple-variants.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-base64-add-support-for-multiple-variants.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kuan-Wei Chiu <visitorckw@gmail.com>
Subject: lib/base64: add support for multiple variants
Date: Fri, 14 Nov 2025 14:00:45 +0800
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 <visitorckw@gmail.com>
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 <david.laight.linux@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/nvme/common/auth.c | 4 +-
include/linux/base64.h | 10 ++++-
lib/base64.c | 62 ++++++++++++++++++++---------------
3 files changed, 46 insertions(+), 30 deletions(-)
--- a/drivers/nvme/common/auth.c~lib-base64-add-support-for-multiple-variants
+++ a/drivers/nvme/common/auth.c
@@ -178,7 +178,7 @@ struct nvme_dhchap_key *nvme_auth_extrac
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
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;
--- a/include/linux/base64.h~lib-base64-add-support-for-multiple-variants
+++ a/include/linux/base64.h
@@ -8,9 +8,15 @@
#include <linux/types.h>
+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 */
--- a/lib/base64.c~lib-base64-add-support-for-multiple-variants
+++ a/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 <linux/kernel.h>
@@ -15,26 +15,31 @@
#include <linux/string.h>
#include <linux/base64.h>
-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 src
*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;
_
Patches currently in -mm which might be from visitorckw@gmail.com are
revert-lib-plistc-enforce-memory-ordering-in-plist_check_list.patch
lib-base64-add-support-for-multiple-variants.patch
lib-base64-optimize-base64_decode-with-reverse-lookup-tables.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-11-14 22:58 UTC | newest]
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2025-11-14 22:58 Andrew Morton
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