Merge pull request #1893 from wangtsiao/master

修复 PEM 读取没有限制 base64 解码输出长度的问题
This commit is contained in:
Zhi Guan
2026-06-13 17:29:42 +08:00
committed by GitHub
5 changed files with 241 additions and 12 deletions

View File

@@ -47,6 +47,8 @@ void base64_encode_finish(BASE64_CTX *ctx, uint8_t *out, int *outlen);
void base64_decode_init(BASE64_CTX *ctx);
int base64_decode_update(BASE64_CTX *ctx, const uint8_t *in, int inlen, uint8_t *out, int *outlen);
int base64_decode_finish(BASE64_CTX *ctx, uint8_t *out, int *outlen);
int base64_decode_update_ex(BASE64_CTX *ctx, const uint8_t *in, int inlen, uint8_t *out, int *outlen, size_t maxout);
int base64_decode_finish_ex(BASE64_CTX *ctx, uint8_t *out, int *outlen, size_t maxout);
int base64_encode_block(unsigned char *t, const unsigned char *f, int dlen);

View File

@@ -211,10 +211,12 @@ void base64_decode_init(BASE64_CTX *ctx)
* - There is extra trailing padding, or data after padding.
* - B64_EOF is detected after an incomplete base64 block.
*/
int base64_decode_update(BASE64_CTX *ctx, const uint8_t *in, int inl, uint8_t *out, int *outl)
int base64_decode_update_ex(BASE64_CTX *ctx, const uint8_t *in, int inl, uint8_t *out, int *outl, size_t maxout)
{
int seof = 0, eof = 0, rv = -1, ret = 0, i, v, tmp, n, decoded_len;
int seof = 0, eof = 0, rv = -1, ret = 0, i, v, tmp, n, decoded_len, block_len, output_len;
unsigned char *d;
unsigned char block[BIN_PER_LINE];
unsigned char *p;
n = ctx->num;
d = ctx->enc_data;
@@ -277,14 +279,27 @@ int base64_decode_update(BASE64_CTX *ctx, const uint8_t *in, int inl, uint8_t *o
}
if (n == 64) {
decoded_len = base64_decode_block(out, d, n);
block_len = n / 4 * 3;
output_len = block_len - eof;
if (eof > block_len
|| (size_t)ret > maxout
|| (size_t)output_len > maxout - (size_t)ret) {
error_print();
rv = -1;
goto end;
}
p = eof ? block : out;
decoded_len = base64_decode_block(p, d, n);
n = 0;
if (decoded_len < 0 || eof > decoded_len) {
rv = -1;
goto end;
}
ret += decoded_len - eof;
out += decoded_len - eof;
if (eof && output_len > 0) {
memcpy(out, block, output_len);
}
ret += output_len;
out += output_len;
}
}
@@ -296,14 +311,28 @@ int base64_decode_update(BASE64_CTX *ctx, const uint8_t *in, int inl, uint8_t *o
tail:
if (n > 0) {
if ((n & 3) == 0) {
decoded_len = base64_decode_block(out, d, n);
block_len = n / 4 * 3;
output_len = block_len - eof;
if (eof > block_len
|| (size_t)ret > maxout
|| (size_t)output_len > maxout - (size_t)ret) {
error_print();
rv = -1;
goto end;
}
p = eof ? block : out;
decoded_len = base64_decode_block(p, d, n);
n = 0;
if (decoded_len < 0 || eof > decoded_len) {
error_print();
rv = -1;
goto end;
}
ret += (decoded_len - eof);
if (eof && output_len > 0) {
memcpy(out, block, output_len);
}
ret += output_len;
out += output_len;
} else if (seof) {
/* EOF in the middle of a base64 block. */
error_print();
@@ -320,6 +349,11 @@ end:
return (rv);
}
int base64_decode_update(BASE64_CTX *ctx, const uint8_t *in, int inl, uint8_t *out, int *outl)
{
return base64_decode_update_ex(ctx, in, inl, out, outl, (size_t)-1);
}
int base64_decode_block(unsigned char *t, const unsigned char *f, int n)
{
int i, ret = 0, a, b, c, d;
@@ -359,12 +393,17 @@ int base64_decode_block(unsigned char *t, const unsigned char *f, int n)
return (ret);
}
int base64_decode_finish(BASE64_CTX *ctx, uint8_t *out, int *outl)
int base64_decode_finish_ex(BASE64_CTX *ctx, uint8_t *out, int *outl, size_t maxout)
{
int i;
*outl = 0;
if (ctx->num != 0) {
if ((ctx->num & 3) != 0
|| (size_t)(ctx->num / 4 * 3) > maxout) {
error_print();
return (-1);
}
i = base64_decode_block(out, ctx->enc_data, ctx->num);
if (i < 0) {
error_print();
@@ -376,3 +415,8 @@ int base64_decode_finish(BASE64_CTX *ctx, uint8_t *out, int *outl)
} else
return (1);
}
int base64_decode_finish(BASE64_CTX *ctx, uint8_t *out, int *outl)
{
return base64_decode_finish_ex(ctx, out, outl, (size_t)-1);
}

View File

@@ -72,8 +72,10 @@ int pem_read(FILE *fp, const char *name, uint8_t *data, size_t *datalen, size_t
char line[80];
char begin_line[80];
char end_line[80];
int len;
BASE64_CTX ctx;
size_t linelen;
int len;
int ret;
snprintf(begin_line, sizeof(begin_line), "-----BEGIN %s-----", name);
snprintf(end_line, sizeof(end_line), "-----END %s-----", name);
@@ -116,12 +118,21 @@ int pem_read(FILE *fp, const char *name, uint8_t *data, size_t *datalen, size_t
break;
}
base64_decode_update(&ctx, (uint8_t *)line, (int)strlen(line), data, &len);
data += len;
linelen = strlen(line);
ret = base64_decode_update_ex(&ctx, (uint8_t *)line, (int)linelen,
data + *datalen, &len, maxlen - *datalen);
if (ret < 0 || len < 0 || (size_t)len > maxlen - *datalen) {
error_print();
return -1;
}
*datalen += len;
}
base64_decode_finish(&ctx, data, &len);
if (base64_decode_finish_ex(&ctx, data + *datalen, &len, maxlen - *datalen) != 1
|| len < 0 || (size_t)len > maxlen - *datalen) {
error_print();
return -1;
}
*datalen += len;
return 1;
}

View File

@@ -61,9 +61,78 @@ static int test_base64(void)
return 1;
}
struct base64_one_byte_buffer {
uint8_t data[1];
uint8_t canary[8];
};
static int test_base64_decode_update_ex_padding(void)
{
const uint8_t in[] = "AA==";
struct base64_one_byte_buffer buf;
uint8_t original_canary[sizeof(buf.canary)];
BASE64_CTX ctx;
int len = 0;
int ret;
memset(&buf, 0xff, sizeof(buf));
memset(buf.canary, 0xcc, sizeof(buf.canary));
memcpy(original_canary, buf.canary, sizeof(original_canary));
base64_decode_init(&ctx);
ret = base64_decode_update_ex(&ctx, in, sizeof(in) - 1,
buf.data, &len, sizeof(buf.data));
if (ret != 0 || len != 1 || buf.data[0] != 0) {
error_print();
return -1;
}
if (memcmp(buf.canary, original_canary, sizeof(original_canary)) != 0) {
error_print();
return -1;
}
printf("%s() ok\n", __FUNCTION__);
return 1;
}
struct base64_two_byte_buffer {
uint8_t data[2];
uint8_t canary[8];
};
static int test_base64_decode_update_ex_maxout(void)
{
const uint8_t in[] = "AAAA";
struct base64_two_byte_buffer buf;
uint8_t original_canary[sizeof(buf.canary)];
BASE64_CTX ctx;
int len = 0;
int ret;
memset(&buf, 0xcc, sizeof(buf));
memcpy(original_canary, buf.canary, sizeof(original_canary));
base64_decode_init(&ctx);
ret = base64_decode_update_ex(&ctx, in, sizeof(in) - 1,
buf.data, &len, sizeof(buf.data));
if (ret != -1 || len != 0) {
error_print();
return -1;
}
if (memcmp(buf.canary, original_canary, sizeof(original_canary)) != 0) {
error_print();
return -1;
}
printf("%s() ok\n", __FUNCTION__);
return 1;
}
int main(void)
{
if (test_base64() != 1) goto err;
if (test_base64_decode_update_ex_padding() != 1) goto err;
if (test_base64_decode_update_ex_maxout() != 1) goto err;
printf("%s all tests passed\n", __FILE__);
return 0;
err:

View File

@@ -235,11 +235,114 @@ static int test_pem_windows_style_without_last_newline(void)
return 1;
}
struct pem_bounded_buffer {
uint8_t data[16];
uint8_t canary[32];
};
static int test_pem_read_maxlen(void)
{
FILE *fp;
const char *file = "test_pem_read_maxlen.pem";
struct pem_bounded_buffer buf;
uint8_t original_canary[sizeof(buf.canary)];
size_t len = 0;
int ret;
int i;
if (!(fp = fopen(file, "wb"))) {
error_print();
return -1;
}
fputs("-----BEGIN TEST-----\n", fp);
for (i = 0; i < 64; i++) {
fputc('A', fp);
}
fputs("\n-----END TEST-----\n", fp);
fclose(fp);
memset(&buf, 0, sizeof(buf));
memset(buf.canary, 0xcc, sizeof(buf.canary));
memcpy(original_canary, buf.canary, sizeof(original_canary));
if (!(fp = fopen(file, "rb"))) {
error_print();
return -1;
}
ret = pem_read(fp, "TEST", buf.data, &len, sizeof(buf.data));
fclose(fp);
if (ret == 1) {
error_print();
return -1;
}
if (len > sizeof(buf.data)) {
error_print();
return -1;
}
if (memcmp(buf.canary, original_canary, sizeof(original_canary)) != 0) {
error_print();
return -1;
}
printf("%s() ok\n", __FUNCTION__);
return 1;
}
struct pem_one_byte_buffer {
uint8_t data[1];
uint8_t canary[8];
};
static int test_pem_read_padding_maxlen(void)
{
FILE *fp;
const char *file = "test_pem_read_padding_maxlen.pem";
struct pem_one_byte_buffer buf;
uint8_t original_canary[sizeof(buf.canary)];
size_t len = 0;
int ret;
if (!(fp = fopen(file, "wb"))) {
error_print();
return -1;
}
fputs("-----BEGIN TEST-----\n", fp);
fputs("AA==\n", fp);
fputs("-----END TEST-----\n", fp);
fclose(fp);
memset(&buf, 0xff, sizeof(buf));
memset(buf.canary, 0xcc, sizeof(buf.canary));
memcpy(original_canary, buf.canary, sizeof(original_canary));
if (!(fp = fopen(file, "rb"))) {
error_print();
return -1;
}
ret = pem_read(fp, "TEST", buf.data, &len, sizeof(buf.data));
fclose(fp);
if (ret != 1 || len != sizeof(buf.data) || buf.data[0] != 0) {
error_print();
return -1;
}
if (memcmp(buf.canary, original_canary, sizeof(original_canary)) != 0) {
error_print();
return -1;
}
printf("%s() ok\n", __FUNCTION__);
return 1;
}
int main(void)
{
if (test_pem_unix_style() != 1) { error_print(); return 1; }
if (test_pem_unix_style_without_last_newline() != 1) { error_print(); return 1; }
if (test_pem_windows_style() != 1) { error_print(); return 1; }
if (test_pem_windows_style_without_last_newline() != 1) { error_print(); return 1; }
if (test_pem_read_maxlen() != 1) { error_print(); return 1; }
if (test_pem_read_padding_maxlen() != 1) { error_print(); return 1; }
return 0;
}