e0c8b4b451

Max Dymond

2026-09-21

SUCCESS Duration: 417s

Subject

base64: avoid repeated input loads when encoding

No binary (build failed)

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

(log yok)

lib/curlx/base64.c+9 -4

@@ -207,10 +207,15 @@ static CURLcode base64_encode(const char *table64,
	return CURLE_OUT_OF_MEMORY;

	while(insize >= 3) {
-	*output++ = table64[in[0] >> 2];
-	*output++ = table64[((in[0] & 0x03) << 4) \| (in[1] >> 4)];
-	*output++ = table64[((in[1] & 0x0F) << 2) \| ((in[2] & 0xC0) >> 6)];
-	*output++ = table64[in[2] & 0x3F];
+	/* Load all three input bytes before storing output, avoiding reloads when
+	the compiler cannot rule out aliasing. Extract four 6-bit indices from
+	the packed value; byte-wise loads avoid alignment and endian issues. */
+	uint32_t bits = ((uint32_t)in[0] << 16) \|
+	((uint32_t)in[1] << 8) \| in[2];
+	*output++ = table64[bits >> 18];
+	*output++ = table64[(bits >> 12) & 0x3F];
+	*output++ = table64[(bits >> 6) & 0x3F];
+	*output++ = table64[bits & 0x3F];
	insize -= 3;
	in += 3;
	}

tests/unit/unit1302.c+24 -0

@@ -162,6 +162,30 @@ static CURLcode test_unit1302(const char *arg)
	curlx_safefree(decoded);
	}

+	{
+	unsigned char binary[256];
+	size_t length;
+	for(i = 0; i < sizeof(binary); i++)
+	binary[i] = (unsigned char)i;
+	for(length = 1; length <= sizeof(binary); length++) {
+	char *encoded;
+	unsigned char *decoded;
+	size_t enclen;
+	size_t declen;
+	result = curlx_base64_encode(binary, length, &encoded, &enclen);
+	abort_unless(result == CURLE_OK, "binary encoding failed");
+	fail_unless(enclen == (length + 2) / 3 * 4, "wrong encoded size");
+	fail_unless(!encoded[enclen], "encoded data is not terminated");
+	result = curlx_base64_decode(encoded, &decoded, &declen);
+	curlx_free(encoded);
+	abort_unless(result == CURLE_OK, "binary decoding failed");
+	fail_unless(declen == length, "wrong decoded size");
+	fail_unless(!memcmp(decoded, binary, length), "wrong decoded data");
+	fail_unless(!decoded[declen], "decoded data is not terminated");
+	curlx_free(decoded);
+	}
+	}
+
	for(i = 0; i < CURL_ARRAYSIZE(url); i++) {
	const struct etest *e = &url[i];
	char *out;