int s2n_stuffer_write_hex(struct s2n_stuffer *stuffer, struct s2n_stuffer *in, uint32_t n)
{
gte_check(s2n_stuffer_space_remaining(stuffer), n * 2);
for (int i = 0; i < n; i++) {
uint8_t c;
GUARD(s2n_stuffer_read_uint8(in, &c));
GUARD(s2n_stuffer_write_uint8_hex(stuffer, c));
}
return 0;
}
static int s2n_stuffer_pem_read_contents(struct s2n_stuffer *pem, struct s2n_stuffer *asn1)
{
uint8_t base64_buf[64] = { 0 };
struct s2n_blob base64__blob = { .data = base64_buf, .size = sizeof(base64_buf) };
struct s2n_stuffer base64_stuffer = {{0}};
GUARD(s2n_stuffer_init(&base64_stuffer, &base64__blob));
while (1) {
char c;
/* Peek to see if the next char is a dash, meaning end of pem_contents */
GUARD(s2n_stuffer_peek_char(pem, &c));
if (c == '-') {
break;
} else {
/* Else, move read pointer forward by 1 byte since we will be consuming it. */
GUARD(s2n_stuffer_skip_read(pem, 1));
}
/* Skip non-base64 characters */
if (!s2n_is_base64_char(c)) {
continue;
}
/* Flush base64_stuffer to asn1 stuffer if we're out of space, and reset base64_stuffer read/write pointers */
if (s2n_stuffer_space_remaining(&base64_stuffer) == 0) {
GUARD(s2n_stuffer_read_base64(&base64_stuffer, asn1));
GUARD(s2n_stuffer_rewrite(&base64_stuffer));
}
/* Copy next char to base64_stuffer */
GUARD(s2n_stuffer_write_bytes(&base64_stuffer, (uint8_t *) &c, 1));
};
/* Flush any remaining bytes to asn1 */
GUARD(s2n_stuffer_read_base64(&base64_stuffer, asn1));
return 0;
}
static int s2n_stuffer_data_from_pem(struct s2n_stuffer *pem, struct s2n_stuffer *asn1, const char *keyword)
{
GUARD(s2n_stuffer_pem_read_begin(pem, keyword));
GUARD(s2n_stuffer_pem_read_contents(pem, asn1));
GUARD(s2n_stuffer_pem_read_end(pem, keyword));
return 0;
}
/* Due to the need to support some older assemblers,
* we cannot use either the compiler intrinsics or
* the RDRAND assembly mnemonic. For this reason,
* we're using the opcode directly (0F C7/6). This
* stores the result in eax.
*
* volatile is important to prevent the compiler from
* re-ordering or optimizing the use of RDRAND.
*/
int s2n_get_rdrand_data(struct s2n_blob *out)
{
#if defined(__x86_64__)||defined(__i386__)
int space_remaining = 0;
struct s2n_stuffer stuffer;
union {
uint64_t u64;
uint8_t u8[8];
} output;
GUARD(s2n_stuffer_init(&stuffer, out));
while((space_remaining = s2n_stuffer_space_remaining(&stuffer))) {
int success = 0;
for (int tries = 0; tries < 10; tries++) {
__asm__ __volatile__(
".byte 0x48;\n"
".byte 0x0f;\n"
".byte 0xc7;\n"
".byte 0xf0;\n"
"adcl $0x00, %%ebx;\n"
:"=b"(success), "=a"(output.u64)
:"b"(0)
:"cc"
);
if (success) {
break;
}
}
if (!success) {
return -1;
}
int data_to_fill = MIN(sizeof(output), space_remaining);
GUARD(s2n_stuffer_write_bytes(&stuffer, output.u8, data_to_fill));
}
return 0;
#else
return -1;
#endif
}
int s2n_stuffer_skip_write(struct s2n_stuffer *stuffer, const uint32_t n)
{
if (s2n_stuffer_space_remaining(stuffer) < n) {
if (stuffer->growable) {
/* Always grow a stuffer by at least 1k */
uint32_t growth = n;
if (growth < 1024) {
growth = 1024;
}
GUARD(s2n_stuffer_resize(stuffer, stuffer->blob.size + growth));
} else {
S2N_ERROR(S2N_ERR_STUFFER_IS_FULL);
}
}
stuffer->write_cursor += n;
stuffer->wiped = 0;
return 0;
}
/**
* Helper function: read n bits of hex data.
*/
static int s2n_stuffer_read_n_bits_hex(struct s2n_stuffer *stuffer, uint8_t n, uint64_t *u)
{
uint8_t hex_data[16];
struct s2n_blob b = { .data = hex_data, .size = n / 4 };
GUARD(s2n_stuffer_read(stuffer, &b));
/* Start with u = 0 */
*u = 0;
for (int i = 0; i < b.size; i++) {
*u <<= 4;
if (b.data[i] >= '0' && b.data[i] <= '9') {
*u |= b.data[i] - '0';
} else if (b.data[i] >= 'a' && b.data[i] <= 'f') {
*u |= b.data[i] - 'a' + 10;
} else if (b.data[i] >= 'A' && b.data[i] <= 'F') {
*u |= b.data[i] - 'A' + 10;
} else {
S2N_ERROR(S2N_ERR_BAD_MESSAGE);
}
}
return 0;
}
int s2n_stuffer_read_hex(struct s2n_stuffer *stuffer, struct s2n_stuffer *out, uint32_t n)
{
gte_check(s2n_stuffer_space_remaining(out), n);
for (int i = 0; i < n; i++) {
uint8_t c;
GUARD(s2n_stuffer_read_uint8_hex(stuffer, &c));
GUARD(s2n_stuffer_write_uint8(out, c));
}
return 0;
}