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Fix decoding asn1 integer.

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It caused overflow.
This commit is contained in:
Pol Henarejos
2022-05-31 01:14:09 +02:00
parent 652551269e
commit 9132dd16f0
1 changed files with 12 additions and 13 deletions
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25
src/hsm/sc_hsm.c
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@@ -1001,25 +1001,24 @@ static int cmd_keypair_gen() {
if (asn1_find_tag(apdu.data, apdu.nc, 0x92, &kdom_size, &kdomd) && kdom_size > 0 && kdomd != NULL)
kdom = *kdomd;
if (memcmp(oid, "\x4\x0\x7F\x0\x7\x2\x2\x2\x1\x2",MIN(oid_len,10)) == 0) { //RSA
size_t ex_len, ks_len;
uint8_t *ex = NULL;
uint8_t *ks = NULL;
asn1_find_tag(p, tout, 0x82, &ex_len, &ex);
asn1_find_tag(p, tout, 0x2, &ks_len, &ks);
int exponent = 65537, key_size = 2048;
if (ex) {
size_t ex_len = 3, ks_len = 2;
uint8_t *ex = NULL, *ks = NULL;
uint32_t exponent = 65537, key_size = 2048;
if (asn1_find_tag(p, tout, 0x82, &ex_len, &ex) && ex_len > 0 && ex != NULL) {
uint8_t *dt = ex;
exponent = 0;
while (ex_len-- > 0) {
exponent = (exponent << 8) | *ex++;
for (int i = 0; i < ex_len; i++) {
exponent = (exponent << 8) | *dt++;
}
}
if (ks) {
if (asn1_find_tag(p, tout, 0x2, &ks_len, &ks) && ks_len > 0 && ks != NULL) {
uint8_t *dt = ks;
key_size = 0;
while (ks_len-- > 0) {
key_size = (key_size << 8) | *ks++;
for (int i = 0; i < ks_len; i++) {
key_size = (key_size << 8) | *dt++;
}
}
printf("KEYPAIR RSA %d\r\n",key_size);
printf("KEYPAIR RSA %ld (%lx)\r\n",key_size,exponent);
mbedtls_rsa_context rsa;
mbedtls_rsa_init(&rsa);
uint8_t index = 0;