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-rw-r--r--src/hpack-dec.c475
1 files changed, 475 insertions, 0 deletions
diff --git a/src/hpack-dec.c b/src/hpack-dec.c
new file mode 100644
index 0000000..052a7c3
--- /dev/null
+++ b/src/hpack-dec.c
@@ -0,0 +1,475 @@
+/*
+ * HPACK decompressor (RFC7541)
+ *
+ * Copyright (C) 2014-2017 Willy Tarreau <willy@haproxy.org>
+ * Copyright (C) 2017 HAProxy Technologies
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <import/ist.h>
+#include <haproxy/chunk.h>
+#include <haproxy/global.h>
+#include <haproxy/h2.h>
+#include <haproxy/hpack-dec.h>
+#include <haproxy/hpack-huff.h>
+#include <haproxy/hpack-tbl.h>
+#include <haproxy/tools.h>
+
+
+#if defined(DEBUG_HPACK)
+#define hpack_debug_printf printf
+#define hpack_debug_hexdump debug_hexdump
+#else
+#define hpack_debug_printf(...) do { } while (0)
+#define hpack_debug_hexdump(...) do { } while (0)
+#endif
+
+/* reads a varint from <raw>'s lowest <b> bits and <len> bytes max (raw included).
+ * returns the 32-bit value on success after updating raw_in and len_in. Forces
+ * len_in to (uint32_t)-1 on truncated input.
+ */
+static uint32_t get_var_int(const uint8_t **raw_in, uint32_t *len_in, int b)
+{
+ uint32_t ret = 0;
+ int len = *len_in;
+ const uint8_t *raw = *raw_in;
+ uint8_t shift = 0;
+
+ len--;
+ ret = *(raw++) & ((1 << b) - 1);
+ if (ret != (uint32_t)((1 << b) - 1))
+ goto end;
+
+ while (len && (*raw & 128)) {
+ ret += ((uint32_t)(*raw++) & 127) << shift;
+ shift += 7;
+ len--;
+ }
+
+ /* last 7 bits */
+ if (!len)
+ goto too_short;
+ len--;
+ ret += ((uint32_t)(*raw++) & 127) << shift;
+
+ end:
+ *raw_in = raw;
+ *len_in = len;
+ return ret;
+
+ too_short:
+ *len_in = (uint32_t)-1;
+ return 0;
+}
+
+/* returns the pseudo-header <idx> corresponds to among the following values :
+ * - 0 = unknown, the header's string needs to be used instead
+ * - 1 = ":authority"
+ * - 2 = ":method"
+ * - 3 = ":path"
+ * - 4 = ":scheme"
+ * - 5 = ":status"
+ */
+static inline int hpack_idx_to_phdr(uint32_t idx)
+{
+ if (idx > 14)
+ return 0;
+
+ idx >>= 1;
+ idx <<= 2;
+ return (0x55554321U >> idx) & 0xF;
+}
+
+/* If <idx> designates a static header, returns <in>. Otherwise allocates some
+ * room from chunk <store> to duplicate <in> into it and returns the string
+ * allocated there. In case of allocation failure, returns a string whose
+ * pointer is NULL.
+ */
+static inline struct ist hpack_alloc_string(struct buffer *store, uint32_t idx,
+ struct ist in)
+{
+ struct ist out;
+
+ if (idx < HPACK_SHT_SIZE)
+ return in;
+
+ out.len = in.len;
+ out.ptr = chunk_newstr(store);
+ if (unlikely(!isttest(out)))
+ return out;
+
+ if (unlikely(store->data + out.len > store->size)) {
+ out.ptr = NULL;
+ return out;
+ }
+
+ store->data += out.len;
+ memcpy(out.ptr, in.ptr, out.len);
+ return out;
+}
+
+/* decode an HPACK frame starting at <raw> for <len> bytes, using the dynamic
+ * headers table <dht>, produces the output into list <list> of <list_size>
+ * entries max, and uses pre-allocated buffer <tmp> for temporary storage (some
+ * list elements will point to it). Some <list> name entries may be made of a
+ * NULL pointer and a len, in which case they will designate a pseudo header
+ * index according to the values returned by hpack_idx_to_phdr() above. The
+ * number of <list> entries used is returned on success, or <0 on failure, with
+ * the opposite one of the HPACK_ERR_* codes. A last element is always zeroed
+ * and is not counted in the number of returned entries. This way the caller
+ * can use list[].n.len == 0 as a marker for the end of list.
+ */
+int hpack_decode_frame(struct hpack_dht *dht, const uint8_t *raw, uint32_t len,
+ struct http_hdr *list, int list_size,
+ struct buffer *tmp)
+{
+ uint32_t idx;
+ uint32_t nlen;
+ uint32_t vlen;
+ uint8_t huff;
+ struct ist name;
+ struct ist value;
+ int must_index;
+ int ret;
+
+ hpack_debug_hexdump(stderr, "[HPACK-DEC] ", (const char *)raw, 0, len);
+
+ chunk_reset(tmp);
+ ret = 0;
+ while (len) {
+ int __maybe_unused code = *raw; /* first byte, only for debugging */
+
+ must_index = 0;
+ if (*raw >= 0x80) {
+ /* indexed header field */
+ if (*raw == 0x80) {
+ hpack_debug_printf("unhandled code 0x%02x (raw=%p, len=%u)\n", *raw, raw, len);
+ ret = -HPACK_ERR_UNKNOWN_OPCODE;
+ goto leave;
+ }
+
+ hpack_debug_printf("%02x: p14: indexed header field : ", code);
+
+ idx = get_var_int(&raw, &len, 7);
+ if (len == (uint32_t)-1) { // truncated
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ hpack_debug_printf(" idx=%u ", idx);
+
+ if (!hpack_valid_idx(dht, idx)) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ value = hpack_alloc_string(tmp, idx, hpack_idx_to_value(dht, idx));
+ if (!isttest(value)) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ /* here we don't index so we can always keep the pseudo header number */
+ name = ist2(NULL, hpack_idx_to_phdr(idx));
+
+ if (!name.len) {
+ name = hpack_alloc_string(tmp, idx, hpack_idx_to_name(dht, idx));
+ if (!isttest(name)) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+ }
+ /* <name> and <value> are now set and point to stable values */
+ }
+ else if (*raw >= 0x20 && *raw <= 0x3f) {
+ /* max dyn table size change */
+ hpack_debug_printf("%02x: p18: dynamic table size update : ", code);
+
+ if (ret) {
+ /* 7541#4.2.1 : DHT size update must only be at the beginning */
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ idx = get_var_int(&raw, &len, 5);
+ if (len == (uint32_t)-1) { // truncated
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+ hpack_debug_printf(" new len=%u\n", idx);
+
+ if (idx > dht->size) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_INVALID_ARGUMENT;
+ goto leave;
+ }
+ continue;
+ }
+ else if (!(*raw & (*raw - 0x10))) {
+ /* 0x00, 0x10, and 0x40 (0x20 and 0x80 were already handled above) */
+
+ /* literal header field without/never/with incremental indexing -- literal name */
+ if (*raw == 0x00)
+ hpack_debug_printf("%02x: p17: literal without indexing : ", code);
+ else if (*raw == 0x10)
+ hpack_debug_printf("%02x: p18: literal never indexed : ", code);
+ else if (*raw == 0x40)
+ hpack_debug_printf("%02x: p16: literal with indexing : ", code);
+
+ if (*raw == 0x40)
+ must_index = 1;
+
+ raw++; len--;
+
+ /* retrieve name */
+ if (!len) { // truncated
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ huff = *raw & 0x80;
+ nlen = get_var_int(&raw, &len, 7);
+ if (len == (uint32_t)-1 || len < nlen) { // truncated
+ hpack_debug_printf("##ERR@%d## (truncated): nlen=%d len=%d\n",
+ __LINE__, (int)nlen, (int)len);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ name = ist2(raw, nlen);
+
+ raw += nlen;
+ len -= nlen;
+
+ if (huff) {
+ char *ntrash = chunk_newstr(tmp);
+ if (!ntrash) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ nlen = huff_dec((const uint8_t *)name.ptr, name.len, ntrash,
+ tmp->size - tmp->data);
+ if (nlen == (uint32_t)-1) {
+ hpack_debug_printf("2: can't decode huffman.\n");
+ ret = -HPACK_ERR_HUFFMAN;
+ goto leave;
+ }
+ hpack_debug_printf(" [name huff %d->%d] ", (int)name.len, (int)nlen);
+
+ tmp->data += nlen; // make room for the value
+ name = ist2(ntrash, nlen);
+ }
+
+ /* retrieve value */
+ if (!len) { // truncated
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ huff = *raw & 0x80;
+ vlen = get_var_int(&raw, &len, 7);
+ if (len == (uint32_t)-1 || len < vlen) { // truncated
+ hpack_debug_printf("##ERR@%d## : vlen=%d len=%d\n",
+ __LINE__, (int)vlen, (int)len);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ value = ist2(raw, vlen);
+ raw += vlen;
+ len -= vlen;
+
+ if (huff) {
+ char *vtrash = chunk_newstr(tmp);
+ if (!vtrash) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ vlen = huff_dec((const uint8_t *)value.ptr, value.len, vtrash,
+ tmp->size - tmp->data);
+ if (vlen == (uint32_t)-1) {
+ hpack_debug_printf("3: can't decode huffman.\n");
+ ret = -HPACK_ERR_HUFFMAN;
+ goto leave;
+ }
+ hpack_debug_printf(" [value huff %d->%d] ", (int)value.len, (int)vlen);
+
+ tmp->data += vlen; // make room for the value
+ value = ist2(vtrash, vlen);
+ }
+
+ /* <name> and <value> are correctly filled here */
+ }
+ else {
+ /* 0x01..0x0f : literal header field without indexing -- indexed name */
+ /* 0x11..0x1f : literal header field never indexed -- indexed name */
+ /* 0x41..0x7f : literal header field with incremental indexing -- indexed name */
+
+ if (*raw <= 0x0f)
+ hpack_debug_printf("%02x: p16: literal without indexing -- indexed name : ", code);
+ else if (*raw >= 0x41)
+ hpack_debug_printf("%02x: p15: literal with indexing -- indexed name : ", code);
+ else
+ hpack_debug_printf("%02x: p16: literal never indexed -- indexed name : ", code);
+
+ /* retrieve name index */
+ if (*raw >= 0x41) {
+ must_index = 1;
+ idx = get_var_int(&raw, &len, 6);
+ }
+ else
+ idx = get_var_int(&raw, &len, 4);
+
+ hpack_debug_printf(" idx=%u ", idx);
+
+ if (len == (uint32_t)-1 || !len) { // truncated
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ if (!hpack_valid_idx(dht, idx)) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ /* retrieve value */
+ huff = *raw & 0x80;
+ vlen = get_var_int(&raw, &len, 7);
+ if (len == (uint32_t)-1 || len < vlen) { // truncated
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TRUNCATED;
+ goto leave;
+ }
+
+ value = ist2(raw, vlen);
+ raw += vlen;
+ len -= vlen;
+
+ if (huff) {
+ char *vtrash = chunk_newstr(tmp);
+ if (!vtrash) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ vlen = huff_dec((const uint8_t *)value.ptr, value.len, vtrash,
+ tmp->size - tmp->data);
+ if (vlen == (uint32_t)-1) {
+ hpack_debug_printf("##ERR@%d## can't decode huffman : ilen=%d osize=%d\n",
+ __LINE__, (int)value.len,
+ (int)(tmp->size - tmp->data));
+ hpack_debug_hexdump(stderr, "[HUFFMAN] ", value.ptr, 0, value.len);
+ ret = -HPACK_ERR_HUFFMAN;
+ goto leave;
+ }
+ tmp->data += vlen; // make room for the value
+ value = ist2(vtrash, vlen);
+ }
+
+ name = IST_NULL;
+ if (!must_index)
+ name.len = hpack_idx_to_phdr(idx);
+
+ if (!name.len) {
+ name = hpack_alloc_string(tmp, idx, hpack_idx_to_name(dht, idx));
+ if (!isttest(name)) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+ }
+ /* <name> and <value> are correctly filled here */
+ }
+
+ /* We must not accept empty header names (forbidden by the spec and used
+ * as a list termination).
+ */
+ if (!name.len) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_INVALID_ARGUMENT;
+ goto leave;
+ }
+
+ /* here's what we have here :
+ * - name.len > 0
+ * - value is filled with either const data or data allocated from tmp
+ * - name.ptr == NULL && !must_index : known pseudo-header #name.len
+ * - name.ptr != NULL || must_index : general header, unknown pseudo-header or index needed
+ */
+ if (ret >= list_size) {
+ hpack_debug_printf("##ERR@%d##\n", __LINE__);
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ list[ret].n = name;
+ list[ret].v = value;
+ ret++;
+
+ if (must_index && hpack_dht_insert(dht, name, value) < 0) {
+ hpack_debug_printf("failed to find some room in the dynamic table\n");
+ ret = -HPACK_ERR_DHT_INSERT_FAIL;
+ goto leave;
+ }
+
+ hpack_debug_printf("\e[1;34m%s\e[0m: ",
+ isttest(name) ? istpad(trash.area, name).ptr : h2_phdr_to_str(name.len));
+
+ hpack_debug_printf("\e[1;35m%s\e[0m [mustidx=%d, used=%d] [n=(%p,%d) v=(%p,%d)]\n",
+ istpad(trash.area, value).ptr, must_index,
+ dht->used,
+ name.ptr, (int)name.len, value.ptr, (int)value.len);
+ }
+
+ if (ret >= list_size) {
+ ret = -HPACK_ERR_TOO_LARGE;
+ goto leave;
+ }
+
+ /* put an end marker */
+ list[ret].n = list[ret].v = IST_NULL;
+ ret++;
+
+ leave:
+ hpack_debug_printf("-- done: ret=%d list_size=%d --\n", (int)ret, (int)list_size);
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 20:17:28 +0000