lib/crypto: powerpc/md5: Drop powerpc optimized MD5 code

MD5 is obsolete, is vulnerable to collision attacks, and is being
replaced by SHA-256 in new systems.  It doesn't make sense to continue
to maintain architecture-optimized implementations of MD5.  Effort
should be spent on modern algorithms.

Indeed, architecture-optimized MD5 code remains only for powerpc.  It
was already removed from mips and sparc, and it never existed for any
other architecture (e.g. x86, arm, or arm64) in the first place.
Earlier the decision was made to keep the powerpc MD5 code for a while
anyway because of someone using it via AF_ALG via libkcapi-hasher
(https://lore.kernel.org/r/f0d771d5-ed70-444c-957a-ad4c16f6c115@csgroup.eu/)

However, with AF_ALG itself now being on its way out due to its
continuous stream of security vulnerabilities
(https://lore.kernel.org/r/20260430011544.31823-1-ebiggers@kernel.org/),
it's also time to be a bit more forceful with nudging people towards
userspace crypto code.  It's always been the better solution anyway, and
it's much more efficient if properly optimized code is used.

Note that the md5-asm.S file contains no privileged instructions and
could be run in userspace just fine.

Thus, we now have two factors going against keeping the powerpc MD5
code.  Different people might weigh these two factors differently, but I
think the two of them together make the removal the clear choice.

Let's remove it.

Acked-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://patch.msgid.link/20260506030005.9698-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index d3904b72dae7a22bdb43be34d8f9c0e858ae3264..591c1c2a7fb31775304f2d4a07e93ad0138b27f6 100644 (file)
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -131,11 +131,6 @@ config CRYPTO_LIB_MD5
          The MD5 and HMAC-MD5 library functions.  Select this if your module
          uses any of the functions from <crypto/md5.h>.
 
-config CRYPTO_LIB_MD5_ARCH
-       bool
-       depends on CRYPTO_LIB_MD5 && !UML
-       default y if PPC
-
 config CRYPTO_LIB_MLDSA
        tristate
        select CRYPTO_LIB_SHA3

diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index 4ad91f3900380180b6ba96ef1ff534f188925ccc..f1e9bf89785ffeca75e35ae1210305ba2cf621ba 100644 (file)
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -187,10 +187,6 @@ clean-files += powerpc/ghashp8-ppc.S
 
 obj-$(CONFIG_CRYPTO_LIB_MD5) += libmd5.o
 libmd5-y := md5.o
-ifeq ($(CONFIG_CRYPTO_LIB_MD5_ARCH),y)
-CFLAGS_md5.o += -I$(src)/$(SRCARCH)
-libmd5-$(CONFIG_PPC) += powerpc/md5-asm.o
-endif # CONFIG_CRYPTO_LIB_MD5_ARCH
 
 ################################################################################
 

diff --git a/lib/crypto/md5.c b/lib/crypto/md5.c
index c4af57db0ea830858b431db2ce1f56ae940b8b71..6bf130cfbbf98c80e239595917f748d38cd66d1b 100644 (file)
--- a/lib/crypto/md5.c
+++ b/lib/crypto/md5.c
@@ -2,8 +2,8 @@
 /*
  * MD5 and HMAC-MD5 library functions
  *
- * md5_block_generic() is derived from cryptoapi implementation, originally
- * based on the public domain implementation written by Colin Plumb in 1993.
+ * md5_block() is derived from cryptoapi implementation, originally based on the
+ * public domain implementation written by Colin Plumb in 1993.
  *
  * Copyright (c) Cryptoapi developers.
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
@@ -31,8 +31,8 @@ static const struct md5_block_state md5_iv = {
 #define MD5STEP(f, w, x, y, z, in, s) \
        (w += f(x, y, z) + in, w = rol32(w, s) + x)
 
-static void md5_block_generic(struct md5_block_state *state,
-                             const u8 data[MD5_BLOCK_SIZE])
+static void md5_block(struct md5_block_state *state,
+                     const u8 data[MD5_BLOCK_SIZE])
 {
        u32 in[MD5_BLOCK_WORDS];
        u32 a, b, c, d;
@@ -119,21 +119,15 @@ static void md5_block_generic(struct md5_block_state *state,
        state->h[3] += d;
 }
 
-static void __maybe_unused md5_blocks_generic(struct md5_block_state *state,
-                                             const u8 *data, size_t nblocks)
+static void md5_blocks(struct md5_block_state *state,
+                      const u8 *data, size_t nblocks)
 {
        do {
-               md5_block_generic(state, data);
+               md5_block(state, data);
                data += MD5_BLOCK_SIZE;
        } while (--nblocks);
 }
 
-#ifdef CONFIG_CRYPTO_LIB_MD5_ARCH
-#include "md5.h" /* $(SRCARCH)/md5.h */
-#else
-#define md5_blocks md5_blocks_generic
-#endif
-
 void md5_init(struct md5_ctx *ctx)
 {
        ctx->state = md5_iv;

diff --git a/lib/crypto/powerpc/md5-asm.S b/lib/crypto/powerpc/md5-asm.S
deleted file mode 100644 (file)
index fa6bc44..0000000
--- a/lib/crypto/powerpc/md5-asm.S
+++ /dev/null
@@ -1,235 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * Fast MD5 implementation for PPC
- *
- * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
- */
-#include <asm/ppc_asm.h>
-#include <asm/asm-offsets.h>
-#include <asm/asm-compat.h>
-
-#define rHP    r3
-#define rWP    r4
-
-#define rH0    r0
-#define rH1    r6
-#define rH2    r7
-#define rH3    r5
-
-#define rW00   r8
-#define rW01   r9
-#define rW02   r10
-#define rW03   r11
-#define rW04   r12
-#define rW05   r14
-#define rW06   r15
-#define rW07   r16
-#define rW08   r17
-#define rW09   r18
-#define rW10   r19
-#define rW11   r20
-#define rW12   r21
-#define rW13   r22
-#define rW14   r23
-#define rW15   r24
-
-#define rT0    r25
-#define rT1    r26
-
-#define INITIALIZE \
-       PPC_STLU r1,-INT_FRAME_SIZE(r1); \
-       SAVE_GPRS(14, 26, r1)           /* push registers onto stack    */
-
-#define FINALIZE \
-       REST_GPRS(14, 26, r1);          /* pop registers from stack     */ \
-       addi    r1,r1,INT_FRAME_SIZE
-
-#ifdef __BIG_ENDIAN__
-#define LOAD_DATA(reg, off) \
-       lwbrx           reg,0,rWP;      /* load data                    */
-#define INC_PTR \
-       addi            rWP,rWP,4;      /* increment per word           */
-#define NEXT_BLOCK                     /* nothing to do                */
-#else
-#define LOAD_DATA(reg, off) \
-       lwz             reg,off(rWP);   /* load data                    */
-#define INC_PTR                                /* nothing to do                */
-#define NEXT_BLOCK \
-       addi            rWP,rWP,64;     /* increment per block          */
-#endif
-
-#define R_00_15(a, b, c, d, w0, w1, p, q, off, k0h, k0l, k1h, k1l) \
-       LOAD_DATA(w0, off)              /*    W                         */ \
-       and             rT0,b,c;        /* 1: f = b and c               */ \
-       INC_PTR                         /*    ptr++                     */ \
-       andc            rT1,d,b;        /* 1: f' = ~b and d             */ \
-       LOAD_DATA(w1, off+4)            /*    W                         */ \
-       or              rT0,rT0,rT1;    /* 1: f = f or f'               */ \
-       addi            w0,w0,k0l;      /* 1: wk = w + k                */ \
-       add             a,a,rT0;        /* 1: a = a + f                 */ \
-       addis           w0,w0,k0h;      /* 1: wk = w + k'               */ \
-       addis           w1,w1,k1h;      /* 2: wk = w + k                */ \
-       add             a,a,w0;         /* 1: a = a + wk                */ \
-       addi            w1,w1,k1l;      /* 2: wk = w + k'               */ \
-       rotrwi          a,a,p;          /* 1: a = a rotl x              */ \
-       add             d,d,w1;         /* 2: a = a + wk                */ \
-       add             a,a,b;          /* 1: a = a + b                 */ \
-       and             rT0,a,b;        /* 2: f = b and c               */ \
-       andc            rT1,c,a;        /* 2: f' = ~b and d             */ \
-       or              rT0,rT0,rT1;    /* 2: f = f or f'               */ \
-       add             d,d,rT0;        /* 2: a = a + f                 */ \
-       INC_PTR                         /*    ptr++                     */ \
-       rotrwi          d,d,q;          /* 2: a = a rotl x              */ \
-       add             d,d,a;          /* 2: a = a + b                 */
-
-#define R_16_31(a, b, c, d, w0, w1, p, q, k0h, k0l, k1h, k1l) \
-       andc            rT0,c,d;        /* 1: f = c and ~d              */ \
-       and             rT1,b,d;        /* 1: f' = b and d              */ \
-       addi            w0,w0,k0l;      /* 1: wk = w + k                */ \
-       or              rT0,rT0,rT1;    /* 1: f = f or f'               */ \
-       addis           w0,w0,k0h;      /* 1: wk = w + k'               */ \
-       add             a,a,rT0;        /* 1: a = a + f                 */ \
-       addi            w1,w1,k1l;      /* 2: wk = w + k                */ \
-       add             a,a,w0;         /* 1: a = a + wk                */ \
-       addis           w1,w1,k1h;      /* 2: wk = w + k'               */ \
-       andc            rT0,b,c;        /* 2: f = c and ~d              */ \
-       rotrwi          a,a,p;          /* 1: a = a rotl x              */ \
-       add             a,a,b;          /* 1: a = a + b                 */ \
-       add             d,d,w1;         /* 2: a = a + wk                */ \
-       and             rT1,a,c;        /* 2: f' = b and d              */ \
-       or              rT0,rT0,rT1;    /* 2: f = f or f'               */ \
-       add             d,d,rT0;        /* 2: a = a + f                 */ \
-       rotrwi          d,d,q;          /* 2: a = a rotl x              */ \
-       add             d,d,a;          /* 2: a = a +b                  */
-
-#define R_32_47(a, b, c, d, w0, w1, p, q, k0h, k0l, k1h, k1l) \
-       xor             rT0,b,c;        /* 1: f' = b xor c              */ \
-       addi            w0,w0,k0l;      /* 1: wk = w + k                */ \
-       xor             rT1,rT0,d;      /* 1: f = f xor f'              */ \
-       addis           w0,w0,k0h;      /* 1: wk = w + k'               */ \
-       add             a,a,rT1;        /* 1: a = a + f                 */ \
-       addi            w1,w1,k1l;      /* 2: wk = w + k                */ \
-       add             a,a,w0;         /* 1: a = a + wk                */ \
-       addis           w1,w1,k1h;      /* 2: wk = w + k'               */ \
-       rotrwi          a,a,p;          /* 1: a = a rotl x              */ \
-       add             d,d,w1;         /* 2: a = a + wk                */ \
-       add             a,a,b;          /* 1: a = a + b                 */ \
-       xor             rT1,rT0,a;      /* 2: f = b xor f'              */ \
-       add             d,d,rT1;        /* 2: a = a + f                 */ \
-       rotrwi          d,d,q;          /* 2: a = a rotl x              */ \
-       add             d,d,a;          /* 2: a = a + b                 */
-
-#define R_48_63(a, b, c, d, w0, w1, p, q, k0h, k0l, k1h, k1l) \
-       addi            w0,w0,k0l;      /* 1: w = w + k                 */ \
-       orc             rT0,b,d;        /* 1: f = b or ~d               */ \
-       addis           w0,w0,k0h;      /* 1: w = w + k'                */ \
-       xor             rT0,rT0,c;      /* 1: f = f xor c               */ \
-       add             a,a,w0;         /* 1: a = a + wk                */ \
-       addi            w1,w1,k1l;      /* 2: w = w + k                 */ \
-       add             a,a,rT0;        /* 1: a = a + f                 */ \
-       addis           w1,w1,k1h;      /* 2: w = w + k'                */ \
-       rotrwi          a,a,p;          /* 1: a = a rotl x              */ \
-       add             a,a,b;          /* 1: a = a + b                 */ \
-       orc             rT0,a,c;        /* 2: f = b or ~d               */ \
-       add             d,d,w1;         /* 2: a = a + wk                */ \
-       xor             rT0,rT0,b;      /* 2: f = f xor c               */ \
-       add             d,d,rT0;        /* 2: a = a + f                 */ \
-       rotrwi          d,d,q;          /* 2: a = a rotl x              */ \
-       add             d,d,a;          /* 2: a = a + b                 */
-
-_GLOBAL(ppc_md5_transform)
-       INITIALIZE
-
-       mtctr           r5
-       lwz             rH0,0(rHP)
-       lwz             rH1,4(rHP)
-       lwz             rH2,8(rHP)
-       lwz             rH3,12(rHP)
-
-ppc_md5_main:
-       R_00_15(rH0, rH1, rH2, rH3, rW00, rW01, 25, 20, 0,
-               0xd76b, -23432, 0xe8c8, -18602)
-       R_00_15(rH2, rH3, rH0, rH1, rW02, rW03, 15, 10, 8,
-               0x2420, 0x70db, 0xc1be, -12562)
-       R_00_15(rH0, rH1, rH2, rH3, rW04, rW05, 25, 20, 16,
-               0xf57c, 0x0faf, 0x4788, -14806)
-       R_00_15(rH2, rH3, rH0, rH1, rW06, rW07, 15, 10, 24,
-               0xa830, 0x4613, 0xfd47, -27391)
-       R_00_15(rH0, rH1, rH2, rH3, rW08, rW09, 25, 20, 32,
-               0x6981, -26408, 0x8b45,  -2129)
-       R_00_15(rH2, rH3, rH0, rH1, rW10, rW11, 15, 10, 40,
-               0xffff, 0x5bb1, 0x895d, -10306)
-       R_00_15(rH0, rH1, rH2, rH3, rW12, rW13, 25, 20, 48,
-               0x6b90, 0x1122, 0xfd98, 0x7193)
-       R_00_15(rH2, rH3, rH0, rH1, rW14, rW15, 15, 10, 56,
-               0xa679, 0x438e, 0x49b4, 0x0821)
-
-       R_16_31(rH0, rH1, rH2, rH3, rW01, rW06, 27, 23,
-               0x0d56, 0x6e0c, 0x1810, 0x6d2d)
-       R_16_31(rH2, rH3, rH0, rH1, rW11, rW00, 18, 12,
-               0x9d02, -32109, 0x124c, 0x2332)
-       R_16_31(rH0, rH1, rH2, rH3, rW05, rW10, 27, 23,
-               0x8ea7, 0x4a33, 0x0245, -18270)
-       R_16_31(rH2, rH3, rH0, rH1, rW15, rW04, 18, 12,
-               0x8eee,  -8608, 0xf258,  -5095)
-       R_16_31(rH0, rH1, rH2, rH3, rW09, rW14, 27, 23,
-               0x969d, -10697, 0x1cbe, -15288)
-       R_16_31(rH2, rH3, rH0, rH1, rW03, rW08, 18, 12,
-               0x3317, 0x3e99, 0xdbd9, 0x7c15)
-       R_16_31(rH0, rH1, rH2, rH3, rW13, rW02, 27, 23,
-               0xac4b, 0x7772, 0xd8cf, 0x331d)
-       R_16_31(rH2, rH3, rH0, rH1, rW07, rW12, 18, 12,
-               0x6a28, 0x6dd8, 0x219a, 0x3b68)
-
-       R_32_47(rH0, rH1, rH2, rH3, rW05, rW08, 28, 21,
-               0x29cb, 0x28e5, 0x4218,  -7788)
-       R_32_47(rH2, rH3, rH0, rH1, rW11, rW14, 16,  9,
-               0x473f, 0x06d1, 0x3aae, 0x3036)
-       R_32_47(rH0, rH1, rH2, rH3, rW01, rW04, 28, 21,
-               0xaea1, -15134, 0x640b, -11295)
-       R_32_47(rH2, rH3, rH0, rH1, rW07, rW10, 16,  9,
-               0x8f4c, 0x4887, 0xbc7c, -22499)
-       R_32_47(rH0, rH1, rH2, rH3, rW13, rW00, 28, 21,
-               0x7eb8, -27199, 0x00ea, 0x6050)
-       R_32_47(rH2, rH3, rH0, rH1, rW03, rW06, 16,  9,
-               0xe01a, 0x22fe, 0x4447, 0x69c5)
-       R_32_47(rH0, rH1, rH2, rH3, rW09, rW12, 28, 21,
-               0xb7f3, 0x0253, 0x59b1, 0x4d5b)
-       R_32_47(rH2, rH3, rH0, rH1, rW15, rW02, 16,  9,
-               0x4701, -27017, 0xc7bd, -19859)
-
-       R_48_63(rH0, rH1, rH2, rH3, rW00, rW07, 26, 22,
-               0x0988,  -1462, 0x4c70, -19401)
-       R_48_63(rH2, rH3, rH0, rH1, rW14, rW05, 17, 11,
-               0xadaf,  -5221, 0xfc99, 0x66f7)
-       R_48_63(rH0, rH1, rH2, rH3, rW12, rW03, 26, 22,
-               0x7e80, -16418, 0xba1e, -25587)
-       R_48_63(rH2, rH3, rH0, rH1, rW10, rW01, 17, 11,
-               0x4130, 0x380d, 0xe0c5, 0x738d)
-       lwz             rW00,0(rHP)
-       R_48_63(rH0, rH1, rH2, rH3, rW08, rW15, 26, 22,
-               0xe837, -30770, 0xde8a, 0x69e8)
-       lwz             rW14,4(rHP)
-       R_48_63(rH2, rH3, rH0, rH1, rW06, rW13, 17, 11,
-               0x9e79, 0x260f, 0x256d, -27941)
-       lwz             rW12,8(rHP)
-       R_48_63(rH0, rH1, rH2, rH3, rW04, rW11, 26, 22,
-               0xab75, -20775, 0x4f9e, -28397)
-       lwz             rW10,12(rHP)
-       R_48_63(rH2, rH3, rH0, rH1, rW02, rW09, 17, 11,
-               0x662b, 0x7c56, 0x11b2, 0x0358)
-
-       add             rH0,rH0,rW00
-       stw             rH0,0(rHP)
-       add             rH1,rH1,rW14
-       stw             rH1,4(rHP)
-       add             rH2,rH2,rW12
-       stw             rH2,8(rHP)
-       add             rH3,rH3,rW10
-       stw             rH3,12(rHP)
-       NEXT_BLOCK
-
-       bdnz            ppc_md5_main
-
-       FINALIZE
-       blr

diff --git a/lib/crypto/powerpc/md5.h b/lib/crypto/powerpc/md5.h
deleted file mode 100644 (file)
index 540b08e..0000000
--- a/lib/crypto/powerpc/md5.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * MD5 optimized for PowerPC
- */
-
-void ppc_md5_transform(u32 *state, const u8 *data, size_t nblocks);
-
-static void md5_blocks(struct md5_block_state *state,
-                      const u8 *data, size_t nblocks)
-{
-       ppc_md5_transform(state->h, data, nblocks);
-}