summaryrefslogtreecommitdiffstats
path: root/src/qpack-dec.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/qpack-dec.c563
1 files changed, 563 insertions, 0 deletions
diff --git a/src/qpack-dec.c b/src/qpack-dec.c
new file mode 100644
index 0000000..97392bb
--- /dev/null
+++ b/src/qpack-dec.c
@@ -0,0 +1,563 @@
+/*
+ * QPACK decompressor
+ *
+ * Copyright 2021 HAProxy Technologies, Frederic Lecaille <flecaille@haproxy.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <import/ist.h>
+#include <haproxy/buf.h>
+#include <haproxy/chunk.h>
+#include <haproxy/h3.h>
+#include <haproxy/mux_quic.h>
+#include <haproxy/qpack-t.h>
+#include <haproxy/qpack-dec.h>
+#include <haproxy/qpack-tbl.h>
+#include <haproxy/hpack-huff.h>
+#include <haproxy/hpack-tbl.h>
+#include <haproxy/http-hdr.h>
+#include <haproxy/tools.h>
+
+#if defined(DEBUG_QPACK)
+#define qpack_debug_printf fprintf
+#define qpack_debug_hexdump debug_hexdump
+#else
+#define qpack_debug_printf(...) do { } while (0)
+#define qpack_debug_hexdump(...) do { } while (0)
+#endif
+
+/* Encoded field line bitmask */
+#define QPACK_EFL_BITMASK 0xf0
+#define QPACK_LFL_WPBNM 0x00 // Literal field line with post-base name reference
+#define QPACK_IFL_WPBI 0x10 // Indexed field line with post-based index
+#define QPACK_LFL_WLN_BIT 0x20 // Literal field line with literal name
+#define QPACK_LFL_WNR_BIT 0x40 // Literal field line with name reference
+#define QPACK_IFL_BIT 0x80 // Indexed field line
+
+/* reads a varint from <raw>'s lowest <b> bits and <len> bytes max (raw included).
+ * returns the 64-bit value on success after updating buf and len_in. Forces
+ * len_in to (uint64_t)-1 on truncated input.
+ * Note that this function is similar to the one used for HPACK (except that is supports
+ * up to 62-bits integers).
+ */
+static uint64_t qpack_get_varint(const unsigned char **buf, uint64_t *len_in, int b)
+{
+ uint64_t ret = 0;
+ int len = *len_in;
+ const uint8_t *raw = *buf;
+ uint8_t shift = 0;
+
+ len--;
+ ret = *raw++ & ((1ULL << b) - 1);
+ if (ret != (uint64_t)((1ULL << b) - 1))
+ goto end;
+
+ while (len && (*raw & 128)) {
+ ret += ((uint64_t)*raw++ & 127) << shift;
+ shift += 7;
+ len--;
+ }
+
+ /* last 7 bits */
+ if (!len)
+ goto too_short;
+
+ len--;
+ ret += ((uint64_t)*raw++ & 127) << shift;
+
+ end:
+ *buf = raw;
+ *len_in = len;
+ return ret;
+
+ too_short:
+ *len_in = (uint64_t)-1;
+ return 0;
+}
+
+/* Decode an encoder stream.
+ *
+ * Returns 0 on success else non-zero.
+ */
+int qpack_decode_enc(struct buffer *buf, int fin, void *ctx)
+{
+ struct qcs *qcs = ctx;
+ size_t len;
+ unsigned char inst;
+
+ /* RFC 9204 4.2. Encoder and Decoder Streams
+ *
+ * The sender MUST NOT close either of these streams, and the receiver
+ * MUST NOT request that the sender close either of these streams.
+ * Closure of either unidirectional stream type MUST be treated as a
+ * connection error of type H3_CLOSED_CRITICAL_STREAM.
+ */
+ if (fin) {
+ qcc_set_error(qcs->qcc, H3_CLOSED_CRITICAL_STREAM, 1);
+ return -1;
+ }
+
+ len = b_data(buf);
+ qpack_debug_hexdump(stderr, "[QPACK-DEC-ENC] ", b_head(buf), 0, len);
+
+ if (!len) {
+ qpack_debug_printf(stderr, "[QPACK-DEC-ENC] empty stream\n");
+ return 0;
+ }
+
+ inst = (unsigned char)*b_head(buf) & QPACK_ENC_INST_BITMASK;
+ if (inst == QPACK_ENC_INST_DUP) {
+ /* Duplicate */
+ }
+ else if (inst & QPACK_ENC_INST_IWNR_BIT) {
+ /* Insert With Name Reference */
+ }
+ else if (inst & QPACK_ENC_INST_IWLN_BIT) {
+ /* Insert with literal name */
+ }
+ else if (inst & QPACK_ENC_INST_SDTC_BIT) {
+ /* Set dynamic table capacity */
+ }
+
+ return 0;
+}
+
+/* Decode an decoder stream.
+ *
+ * Returns 0 on success else non-zero.
+ */
+int qpack_decode_dec(struct buffer *buf, int fin, void *ctx)
+{
+ struct qcs *qcs = ctx;
+ size_t len;
+ unsigned char inst;
+
+ /* RFC 9204 4.2. Encoder and Decoder Streams
+ *
+ * The sender MUST NOT close either of these streams, and the receiver
+ * MUST NOT request that the sender close either of these streams.
+ * Closure of either unidirectional stream type MUST be treated as a
+ * connection error of type H3_CLOSED_CRITICAL_STREAM.
+ */
+ if (fin) {
+ qcc_set_error(qcs->qcc, H3_CLOSED_CRITICAL_STREAM, 1);
+ return -1;
+ }
+
+ len = b_data(buf);
+ qpack_debug_hexdump(stderr, "[QPACK-DEC-DEC] ", b_head(buf), 0, len);
+
+ if (!len) {
+ qpack_debug_printf(stderr, "[QPACK-DEC-DEC] empty stream\n");
+ return 0;
+ }
+
+ inst = (unsigned char)*b_head(buf) & QPACK_DEC_INST_BITMASK;
+ if (inst == QPACK_DEC_INST_ICINC) {
+ /* Insert count increment */
+ }
+ else if (inst & QPACK_DEC_INST_SACK) {
+ /* Section Acknowledgment */
+ }
+ else if (inst & QPACK_DEC_INST_SCCL) {
+ /* Stream cancellation */
+ }
+
+ return 0;
+}
+
+/* Decode a field section prefix made of <enc_ric> and <db> two varints.
+ * Also set the 'S' sign bit for <db>.
+ * Return a negative error if failed, 0 if not.
+ */
+static int qpack_decode_fs_pfx(uint64_t *enc_ric, uint64_t *db, int *sign_bit,
+ const unsigned char **raw, uint64_t *len)
+{
+ *enc_ric = qpack_get_varint(raw, len, 8);
+ if (*len == (uint64_t)-1)
+ return -QPACK_ERR_RIC;
+
+ *sign_bit = **raw & 0x8;
+ *db = qpack_get_varint(raw, len, 7);
+ if (*len == (uint64_t)-1)
+ return -QPACK_ERR_DB;
+
+ return 0;
+}
+
+/* Decode a field section from the <raw> buffer of <len> bytes. Each parsed
+ * header is inserted into <list> of <list_size> entries max and uses <tmp> as
+ * a storage for some elements pointing into it. An end marker is inserted at
+ * the end of the list with empty strings as name/value.
+ *
+ * Returns the number of headers inserted into list excluding the end marker.
+ * In case of error, a negative code QPACK_ERR_* is returned.
+ */
+int qpack_decode_fs(const unsigned char *raw, uint64_t len, struct buffer *tmp,
+ struct http_hdr *list, int list_size)
+{
+ struct ist name, value;
+ uint64_t enc_ric, db;
+ int s;
+ unsigned int efl_type;
+ int ret;
+ int hdr_idx = 0;
+
+ qpack_debug_hexdump(stderr, "[QPACK-DEC-FS] ", (const char *)raw, 0, len);
+
+ /* parse field section prefix */
+ ret = qpack_decode_fs_pfx(&enc_ric, &db, &s, &raw, &len);
+ if (ret < 0) {
+ qpack_debug_printf(stderr, "##ERR@%d(%d)\n", __LINE__, ret);
+ goto out;
+ }
+
+ chunk_reset(tmp);
+ qpack_debug_printf(stderr, "enc_ric: %llu db: %llu s=%d\n",
+ (unsigned long long)enc_ric, (unsigned long long)db, !!s);
+ /* Decode field lines */
+ while (len) {
+ if (hdr_idx >= list_size) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TOO_LARGE;
+ goto out;
+ }
+
+ /* parse field line representation */
+ efl_type = *raw & QPACK_EFL_BITMASK;
+ qpack_debug_printf(stderr, "efl_type=0x%02x\n", efl_type);
+
+ if (efl_type == QPACK_LFL_WPBNM) {
+ /* Literal field line with post-base name reference
+ * TODO adjust this when dynamic table support is implemented.
+ */
+#if 0
+ uint64_t index __maybe_unused, length;
+ unsigned int n __maybe_unused, h __maybe_unused;
+
+ qpack_debug_printf(stderr, "literal field line with post-base name reference:");
+ n = *raw & 0x08;
+ index = qpack_get_varint(&raw, &len, 3);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " n=%d index=%llu", !!n, (unsigned long long)index);
+ h = *raw & 0x80;
+ length = qpack_get_varint(&raw, &len, 7);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " h=%d length=%llu", !!h, (unsigned long long)length);
+
+ if (len < length) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ raw += length;
+ len -= length;
+#endif
+
+ /* RFC9204 2.2.3 Invalid References
+ *
+ * If the decoder encounters a reference in a field line representation
+ * to a dynamic table entry that has already been evicted or that has an
+ * absolute index greater than or equal to the declared Required Insert
+ * Count (Section 4.5.1), it MUST treat this as a connection error of
+ * type QPACK_DECOMPRESSION_FAILED.
+ */
+ return -QPACK_DECOMPRESSION_FAILED;
+ }
+ else if (efl_type == QPACK_IFL_WPBI) {
+ /* Indexed field line with post-base index
+ * TODO adjust this when dynamic table support is implemented.
+ */
+#if 0
+ uint64_t index __maybe_unused;
+
+ qpack_debug_printf(stderr, "indexed field line with post-base index:");
+ index = qpack_get_varint(&raw, &len, 4);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " index=%llu", (unsigned long long)index);
+#endif
+
+ /* RFC9204 2.2.3 Invalid References
+ *
+ * If the decoder encounters a reference in a field line representation
+ * to a dynamic table entry that has already been evicted or that has an
+ * absolute index greater than or equal to the declared Required Insert
+ * Count (Section 4.5.1), it MUST treat this as a connection error of
+ * type QPACK_DECOMPRESSION_FAILED.
+ */
+ return -QPACK_DECOMPRESSION_FAILED;
+ }
+ else if (efl_type & QPACK_IFL_BIT) {
+ /* Indexed field line */
+ uint64_t index;
+ unsigned int static_tbl;
+
+ qpack_debug_printf(stderr, "indexed field line:");
+ static_tbl = efl_type & 0x40;
+ index = qpack_get_varint(&raw, &len, 6);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ if (static_tbl && index < QPACK_SHT_SIZE) {
+ name = qpack_sht[index].n;
+ value = qpack_sht[index].v;
+ }
+ else {
+ /* RFC9204 2.2.3 Invalid References
+ *
+ * If the decoder encounters a reference in a field line representation
+ * to a dynamic table entry that has already been evicted or that has an
+ * absolute index greater than or equal to the declared Required Insert
+ * Count (Section 4.5.1), it MUST treat this as a connection error of
+ * type QPACK_DECOMPRESSION_FAILED.
+ *
+ * TODO adjust this when dynamic table support is implemented.
+ */
+ return -QPACK_DECOMPRESSION_FAILED;
+ }
+
+ qpack_debug_printf(stderr, " t=%d index=%llu", !!static_tbl, (unsigned long long)index);
+ }
+ else if (efl_type & QPACK_LFL_WNR_BIT) {
+ /* Literal field line with name reference */
+ uint64_t index, length;
+ unsigned int static_tbl, n __maybe_unused, h;
+
+ qpack_debug_printf(stderr, "Literal field line with name reference:");
+ n = efl_type & 0x20;
+ static_tbl = efl_type & 0x10;
+ index = qpack_get_varint(&raw, &len, 4);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ if (static_tbl && index < QPACK_SHT_SIZE) {
+ name = qpack_sht[index].n;
+ }
+ else {
+ /* RFC9204 2.2.3 Invalid References
+ *
+ * If the decoder encounters a reference in a field line representation
+ * to a dynamic table entry that has already been evicted or that has an
+ * absolute index greater than or equal to the declared Required Insert
+ * Count (Section 4.5.1), it MUST treat this as a connection error of
+ * type QPACK_DECOMPRESSION_FAILED.
+ *
+ * TODO adjust this when dynamic table support is implemented.
+ */
+ return -QPACK_DECOMPRESSION_FAILED;
+ }
+
+ qpack_debug_printf(stderr, " n=%d t=%d index=%llu", !!n, !!static_tbl, (unsigned long long)index);
+ h = *raw & 0x80;
+ length = qpack_get_varint(&raw, &len, 7);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " h=%d length=%llu", !!h, (unsigned long long)length);
+ if (h) {
+ char *trash;
+ int nlen;
+
+ trash = chunk_newstr(tmp);
+ if (!trash) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_DECOMPRESSION_FAILED;
+ goto out;
+ }
+ nlen = huff_dec(raw, length, trash, tmp->size - tmp->data);
+ if (nlen == (uint32_t)-1) {
+ qpack_debug_printf(stderr, " can't decode huffman.\n");
+ ret = -QPACK_ERR_HUFFMAN;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " [name huff %d->%d '%s']", (int)length, (int)nlen, trash);
+ /* makes an ist from tmp storage */
+ b_add(tmp, nlen);
+ value = ist2(trash, nlen);
+ }
+ else {
+ value = ist2(raw, length);
+ }
+
+ if (len < length) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ raw += length;
+ len -= length;
+ }
+ else if (efl_type & QPACK_LFL_WLN_BIT) {
+ /* Literal field line with literal name */
+ unsigned int n __maybe_unused, hname, hvalue;
+ uint64_t name_len, value_len;
+
+ qpack_debug_printf(stderr, "Literal field line with literal name:");
+ n = *raw & 0x10;
+ hname = *raw & 0x08;
+ name_len = qpack_get_varint(&raw, &len, 3);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " n=%d hname=%d name_len=%llu", !!n, !!hname, (unsigned long long)name_len);
+ /* Name string */
+
+ if (len < name_len) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ if (hname) {
+ char *trash;
+ int nlen;
+
+ trash = chunk_newstr(tmp);
+ if (!trash) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_DECOMPRESSION_FAILED;
+ goto out;
+ }
+ nlen = huff_dec(raw, name_len, trash, tmp->size - tmp->data);
+ if (nlen == (uint32_t)-1) {
+ qpack_debug_printf(stderr, " can't decode huffman.\n");
+ ret = -QPACK_ERR_HUFFMAN;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " [name huff %d->%d '%s']", (int)name_len, (int)nlen, trash);
+ /* makes an ist from tmp storage */
+ b_add(tmp, nlen);
+ name = ist2(trash, nlen);
+ }
+ else {
+ name = ist2(raw, name_len);
+ }
+
+ raw += name_len;
+ len -= name_len;
+
+ hvalue = *raw & 0x80;
+ value_len = qpack_get_varint(&raw, &len, 7);
+ if (len == (uint64_t)-1) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " hvalue=%d value_len=%llu", !!hvalue, (unsigned long long)value_len);
+
+ if (len < value_len) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TRUNCATED;
+ goto out;
+ }
+
+ if (hvalue) {
+ char *trash;
+ int nlen;
+
+ trash = chunk_newstr(tmp);
+ if (!trash) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_DECOMPRESSION_FAILED;
+ goto out;
+ }
+ nlen = huff_dec(raw, value_len, trash, tmp->size - tmp->data);
+ if (nlen == (uint32_t)-1) {
+ qpack_debug_printf(stderr, " can't decode huffman.\n");
+ ret = -QPACK_ERR_HUFFMAN;
+ goto out;
+ }
+
+ qpack_debug_printf(stderr, " [name huff %d->%d '%s']", (int)value_len, (int)nlen, trash);
+ /* makes an ist from tmp storage */
+ b_add(tmp, nlen);
+ value = ist2(trash, nlen);
+ }
+ else {
+ value = ist2(raw, value_len);
+ }
+
+ raw += value_len;
+ len -= value_len;
+ }
+
+ /* We must not accept empty header names (forbidden by the spec and used
+ * as a list termination).
+ */
+ if (!name.len) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_DECOMPRESSION_FAILED;
+ goto out;
+ }
+
+ list[hdr_idx].n = name;
+ list[hdr_idx].v = value;
+ ++hdr_idx;
+
+ qpack_debug_printf(stderr, "\n");
+ }
+
+ if (hdr_idx >= list_size) {
+ qpack_debug_printf(stderr, "##ERR@%d\n", __LINE__);
+ ret = -QPACK_ERR_TOO_LARGE;
+ goto out;
+ }
+
+ /* put an end marker */
+ list[hdr_idx].n = list[hdr_idx].v = IST_NULL;
+ ret = hdr_idx;
+
+ out:
+ qpack_debug_printf(stderr, "-- done: ret=%d\n", ret);
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-13 06:03:41 +0000