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ANDROID: crypto: lib/aes - add vendor hooks for AES library routines

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Add vendor hooks that will allow the FIPS140 kernel module to override
the implementations of the AES library routines. The FIPS 140 versions
are identical to the normal ones, but their code and rodata will have been
integrity checked at module load time.

Bug: 153614920
Bug: 188620248
Change-Id: I5711fc42eced903565fd3c8d41ca7cdd82641148
Signed-off-by: Ard Biesheuvel <ardb@google.com>
This commit is contained in:
Ard Biesheuvel 2021-04-12 13:05:54 +02:00
parent 7a689ebc67
commit 9c556792b7
3 changed files with 51 additions and 2 deletions
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3
drivers/android/vendor_hooks.c
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@ -323,3 +323,6 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_balance_anon_file_reclaim);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_cpuidle_psci_enter);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_cpuidle_psci_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_sha256);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_aes_expandkey);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_aes_encrypt);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_aes_decrypt);

28
include/trace/hooks/fips140.h
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@ -8,12 +8,15 @@
#include <linux/tracepoint.h>
#include <trace/hooks/vendor_hooks.h>
struct crypto_aes_ctx;
/*
* This hook exists only for the benefit of the FIPS140 crypto module, which
* uses it to swap out the underlying implementation with one that is integrity
* These hooks exist only for the benefit of the FIPS140 crypto module, which
* uses them to swap out the underlying implementation with one that is integrity
* checked as per FIPS 140 requirements. No other uses are allowed or
* supported.
*/
DECLARE_HOOK(android_vh_sha256,
TP_PROTO(const u8 *data,
unsigned int len,
@ -21,6 +24,27 @@ DECLARE_HOOK(android_vh_sha256,
int *hook_inuse),
TP_ARGS(data, len, out, hook_inuse));
DECLARE_HOOK(android_vh_aes_expandkey,
TP_PROTO(struct crypto_aes_ctx *ctx,
const u8 *in_key,
unsigned int key_len,
int *err),
TP_ARGS(ctx, in_key, key_len, err));
DECLARE_HOOK(android_vh_aes_encrypt,
TP_PROTO(const struct crypto_aes_ctx *ctx,
u8 *out,
const u8 *in,
int *hook_inuse),
TP_ARGS(ctx, out, in, hook_inuse));
DECLARE_HOOK(android_vh_aes_decrypt,
TP_PROTO(const struct crypto_aes_ctx *ctx,
u8 *out,
const u8 *in,
int *hook_inuse),
TP_ARGS(ctx, out, in, hook_inuse));
#endif /* _TRACE_HOOK_FIPS140_H */
/* This part must be outside protection */

22
lib/crypto/aes.c
View File

@ -7,6 +7,7 @@
#include <linux/crypto.h>
#include <linux/module.h>
#include <asm/unaligned.h>
#include <trace/hooks/fips140.h>
/*
* Emit the sbox as volatile const to prevent the compiler from doing
@ -189,6 +190,13 @@ int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
u32 rc, i, j;
int err;
#if defined(CONFIG_CRYPTO_FIPS140) && !defined(BUILD_FIPS140_KO)
err = -(MAX_ERRNO + 1);
trace_android_vh_aes_expandkey(ctx, in_key, key_len, &err);
if (err != -(MAX_ERRNO + 1))
return err;
#endif
err = aes_check_keylen(key_len);
if (err)
return err;
@ -261,6 +269,13 @@ void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in)
int rounds = 6 + ctx->key_length / 4;
u32 st0[4], st1[4];
int round;
#if defined(CONFIG_CRYPTO_FIPS140) && !defined(BUILD_FIPS140_KO)
int hook_inuse = 0;
trace_android_vh_aes_encrypt(ctx, out, in, &hook_inuse);
if (hook_inuse)
return;
#endif
st0[0] = ctx->key_enc[0] ^ get_unaligned_le32(in);
st0[1] = ctx->key_enc[1] ^ get_unaligned_le32(in + 4);
@ -312,6 +327,13 @@ void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in)
int rounds = 6 + ctx->key_length / 4;
u32 st0[4], st1[4];
int round;
#if defined(CONFIG_CRYPTO_FIPS140) && !defined(BUILD_FIPS140_KO)
int hook_inuse = 0;
trace_android_vh_aes_decrypt(ctx, out, in, &hook_inuse);
if (hook_inuse)
return;
#endif
st0[0] = ctx->key_dec[0] ^ get_unaligned_le32(in);
st0[1] = ctx->key_dec[1] ^ get_unaligned_le32(in + 4);