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Size fast math mem-zero checks by the integer's digit count #12068

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Merged
JacobBarthelmeh merged 1 commit into from
Nov 9, 2026
Merged

Size fast math mem-zero checks by the integer's digit count #12068

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4 changes: 4 additions & 0 deletions .github/configs/os-check-linux.json
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Original file line number Diff line number Diff line change
Expand Up @@ -271,6 +271,10 @@
"comment": "The user_settings.h header-driven build path is distinct from the autotools-driven --enable-all path; full make check.",
"user_settings": "examples/configs/user_settings_all.h",
"configure": ["--enable-usersettings"]},
{"name": "fastmath-alt-ecc-check-mem-zero", "minutes": 2.0,
"comment": "Only entry that checks mem-zero with ALT_ECC_SIZE fast math, where ECC integers are alt_fp_ints smaller than an fp_int.",
"configure": ["--enable-fastmath",
"CPPFLAGS=-DALT_ECC_SIZE -DWOLFSSL_CHECK_MEM_ZERO"]},
{"name": "she-ext-cryptocb-sw-default", "minutes": 1.9,
"configure": ["--enable-she=extended", "--enable-cryptocb", "--enable-cryptocbutils",
"CPPFLAGS=-DWC_SHE_SW_DEFAULT"]},
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20 changes: 18 additions & 2 deletions wolfcrypt/src/tfm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6061,14 +6061,30 @@ int mp_lshd (mp_int * a, int b)
}

#ifdef WOLFSSL_CHECK_MEM_ZERO
/* Number of bytes of digits in the integer. With ALT_ECC_SIZE, an ECC integer
* is an alt_fp_int with fewer digits than an fp_int, so use the size it was
* initialized with, as fp_forcezero() does, to stay inside it. */
static size_t mp_memzero_len(mp_int* a)
{
#if defined(ALT_ECC_SIZE) || defined(HAVE_WOLF_BIGINT)
return (size_t)a->size * sizeof(fp_digit);
#else
return sizeof(a->dp);
#endif
}

void mp_memzero_add(const char* name, mp_int* a)
{
wc_MemZero_Add(name, a->dp, sizeof(a->dp));
if (a != NULL) {
wc_MemZero_Add(name, a->dp, mp_memzero_len(a));
}
}

void mp_memzero_check(mp_int* a)
{
wc_MemZero_Check(a->dp, sizeof(a->dp));
if (a != NULL) {
wc_MemZero_Check(a->dp, mp_memzero_len(a));
}
}
#endif /* WOLFSSL_CHECK_MEM_ZERO */

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