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Further improve readability

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This commit is contained in:
shchmue 2022-11-02 18:36:39 -07:00
parent cc4f8bf1f6
commit c7d90ec8ca
8 changed files with 195 additions and 207 deletions
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70
bdk/sec/se.c
View file

@ -718,76 +718,6 @@ out:;
return res;
}
// _mgf1_xor() and rsa_oaep_decode were derived from Atmosphère
static void _mgf1_xor(void *masked, u32 masked_size, const void *seed, u32 seed_size)
{
u8 cur_hash[0x20] __attribute__((aligned(4)));
u8 hash_buf[0xe4] __attribute__((aligned(4)));
u32 hash_buf_size = seed_size + 4;
memcpy(hash_buf, seed, seed_size);
u32 round_num = 0;
u8 *p_out = (u8 *)masked;
while (masked_size) {
u32 cur_size = MIN(masked_size, 0x20);
for (u32 i = 0; i < 4; i++)
hash_buf[seed_size + 3 - i] = (round_num >> (8 * i)) & 0xff;
round_num++;
se_calc_sha256_oneshot(cur_hash, hash_buf, hash_buf_size);
for (unsigned int i = 0; i < cur_size; i++) {
*p_out ^= cur_hash[i];
p_out++;
}
masked_size -= cur_size;
}
}
u32 se_rsa_oaep_decode(void *dst, u32 dst_size, const void *label_digest, u32 label_digest_size, u8 *buf, u32 buf_size)
{
if (dst_size <= 0 || buf_size < 0x43 || label_digest_size != 0x20)
return 0;
bool is_valid = buf[0] == 0;
u32 db_len = buf_size - 0x21;
u8 *seed = buf + 1;
u8 *db = seed + 0x20;
_mgf1_xor(seed, 0x20, db, db_len);
_mgf1_xor(db, db_len, seed, 0x20);
is_valid &= memcmp(label_digest, db, 0x20) ? 0 : 1;
db += 0x20;
db_len -= 0x20;
int msg_ofs = 0;
int looking_for_one = 1;
int invalid_db_padding = 0;
int is_zero;
int is_one;
for (int i = 0; i < db_len; )
{
is_zero = (db[i] == 0);
is_one = (db[i] == 1);
msg_ofs += (looking_for_one & is_one) * (++i);
looking_for_one &= ~is_one;
invalid_db_padding |= (looking_for_one & ~is_zero);
}
is_valid &= (invalid_db_padding == 0);
const u32 msg_size = MIN(dst_size, is_valid * (db_len - msg_ofs));
memcpy(dst, db + msg_ofs, msg_size);
return msg_size;
}
void se_get_aes_keys(u8 *buf, u8 *keys, u32 keysize)
{
u8 *aligned_buf = (u8 *)ALIGN((u32)buf, 0x40);

1
bdk/sec/se.h
View file

@ -49,6 +49,5 @@ int se_calc_sha256(void *hash, u32 *msg_left, const void *src, u32 src_size, u64
int se_calc_sha256_oneshot(void *hash, const void *src, u32 src_size);
int se_calc_sha256_finalize(void *hash, u32 *msg_left);
int se_calc_hmac_sha256(void *dst, const void *src, u32 src_size, const void *key, u32 key_size);
u32 se_rsa_oaep_decode(void *dst, u32 dst_size, const void *label_digest, u32 label_digest_size, u8 *buf, u32 buf_size);
#endif