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PK: avoid 1kB stack buffer in rsa_alt_check_pair()

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Again, guarded by RSA_C, so use of heap is clearly OK.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This commit is contained in:
Manuel Pégourié-Gonnard
2026-02-23 10:01:29 +01:00
parent a76d2129ba
commit 06830d69df
1 changed files with 12 additions and 5 deletions
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17
library/pk_wrap.c
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@@ -1336,7 +1336,6 @@ static int rsa_alt_check_pair(mbedtls_pk_context *pub, mbedtls_pk_context *prv,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng)
{
unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
unsigned char hash[32];
size_t sig_len = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -1345,21 +1344,29 @@ static int rsa_alt_check_pair(mbedtls_pk_context *pub, mbedtls_pk_context *prv,
return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
}
size_t sig_size = (rsa_get_bitlen(pub) + 7) / 8;
unsigned char *sig = mbedtls_calloc(1, sig_size);
if (sig == NULL) {
return MBEDTLS_ERR_PK_ALLOC_FAILED;
}
memset(hash, 0x2a, sizeof(hash));
if ((ret = rsa_alt_sign_wrap(prv, MBEDTLS_MD_NONE,
hash, sizeof(hash),
sig, sizeof(sig), &sig_len,
sig, sig_size, &sig_len,
f_rng, p_rng)) != 0) {
return ret;
goto cleanup;
}
if (rsa_verify_wrap(pub, MBEDTLS_MD_NONE,
hash, sizeof(hash), sig, sig_len) != 0) {
return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
}
return 0;
cleanup:
mbedtls_free(sig);
return ret;
}
#endif /* MBEDTLS_RSA_C */