boot/shim: add patch to fix builds with -O3 / -Ofast

Fixes:
https://autobuild.buildroot.net/results/c6ad52a048ba030bb1adc3ee1aeb69ef880cbdad/
https://autobuild.buildroot.net/results/136d1afc2ecacea6a4e12b915073e3eaf5c8ca01/
https://autobuild.buildroot.net/results/a3f293371f6bd0125dc7baa5afb64373e4383f4f/

Shim contains an embedded copy of OpenSSL.  Depending on the optimization
level, an error is triggered from make_kn():

In function 'make_kn',
    inlined from 'make_kn' at crypto/cmac/cmac.c:81:13,
    inlined from 'CMAC_Init' at crypto/cmac/cmac.c:205:9:
crypto/cmac/cmac.c:92:20: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
   92 |         k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
      |         ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
crypto/cmac/cmac.c: In function 'CMAC_Init':
crypto/cmac/cmac.c:69:19: note: at offset 2147483647 into destination object 'k1' of size 32
   69 |     unsigned char k1[EVP_MAX_BLOCK_LENGTH];
      |                   ^~

Fix it by including a patch submitted upstream which backports an upstream
OpenSSL change to workaround this.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>
This commit is contained in:
Peter Korsgaard
2026-06-15 22:25:31 +02:00
committed by Julien Olivain
parent 6ea98e0f1e
commit 96408d1313

View File

@@ -0,0 +1,72 @@
From 7aee873d6f6b0737dfe566fc8c5cd4eaada9bd5e Mon Sep 17 00:00:00 2001
From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Date: Mon, 8 Apr 2024 11:56:06 +0200
Subject: [PATCH] cmac.c: optimize make_kn and move zero_iv to const segment.
Backport
https://github.com/openssl/openssl/commit/03cf7e784caa4c61febbf249be63cbae3e368ac9
to fix the following k1 stringop-overflow:
In function 'make_kn',
inlined from 'make_kn' at crypto/cmac/cmac.c:81:13,
inlined from 'CMAC_Init' at crypto/cmac/cmac.c:205:9:
crypto/cmac/cmac.c:92:20: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
92 | k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
| ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
crypto/cmac/cmac.c: In function 'CMAC_Init':
crypto/cmac/cmac.c:69:19: note: at offset [-2147483649, -1] into destination object 'k1' of size 32
69 | unsigned char k1[EVP_MAX_BLOCK_LENGTH];
| ^~
Fixes:
- http://autobuild.buildroot.org/results/97b6333cdc7bad24aba7af1b04890679e0058299
Upstream: https://github.com/rhboot/shim/pull/652
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
Cryptlib/OpenSSL/crypto/cmac/cmac.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/Cryptlib/OpenSSL/crypto/cmac/cmac.c b/Cryptlib/OpenSSL/crypto/cmac/cmac.c
index 2954b6eb..27dbfaac 100644
--- a/Cryptlib/OpenSSL/crypto/cmac/cmac.c
+++ b/Cryptlib/OpenSSL/crypto/cmac/cmac.c
@@ -78,18 +78,17 @@ struct CMAC_CTX_st {
/* Make temporary keys K1 and K2 */
-static void make_kn(unsigned char *k1, unsigned char *l, int bl)
+static void make_kn(unsigned char *k1, const unsigned char *l, int bl)
{
int i;
+ unsigned char c = l[0], carry = c>>7, cnext;
+
/* Shift block to left, including carry */
- for (i = 0; i < bl; i++) {
- k1[i] = l[i] << 1;
- if (i < bl - 1 && l[i + 1] & 0x80)
- k1[i] |= 1;
- }
+ for (i = 0; i < bl-1; i++, c = cnext)
+ k1[i] = (c << 1) | ((cnext=l[i+1]) >> 7);
+
/* If MSB set fixup with R */
- if (l[0] & 0x80)
- k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
+ k1[i] = (c << 1) ^ ((0-carry)&(bl==16?0x87:0x1b));
}
CMAC_CTX *CMAC_CTX_new(void)
@@ -151,7 +150,7 @@ int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
const EVP_CIPHER *cipher, ENGINE *impl)
{
- static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
+ static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = {0};
#ifdef OPENSSL_FIPS
if (FIPS_mode()) {
/* If we have an ENGINE need to allow non FIPS */
--
2.47.3