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HTTP/2: fixed connection finalization. All streams in connection must be finalized before the connection itself can be finalized and all related memory is freed. That's not always possible on the current event loop iteration. Thus when the last stream is finalized, it sets the special read event handler ngx_http_v2_handle_connection_handler() and posts the event. Previously, this handler didn't check the connection state and could call the regular event handler on a connection that was already in finalization stage. In the worst case that could lead to a segmentation fault, since some data structures aren't supposed to be used during connection finalization. Particularly, the waiting queue can contain already freed streams, so the WINDOW_UPDATE frame received by that moment could trigger accessing to these freed streams. Now, the connection error flag is explicitly checked in ngx_http_v2_handle_connection_handler().
author Valentin Bartenev <vbart@nginx.com>
date Wed, 29 Mar 2017 20:21:01 +0300
parents dcfe355dfda4
children
line wrap: on
line source


/*
 * Copyright (C) Nginx, Inc.
 * Copyright (C) Valentin V. Bartenev
 * Copyright (C) 2015 Vlad Krasnov
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef struct {
    uint32_t  code;
    uint32_t  len;
} ngx_http_v2_huff_encode_code_t;


static ngx_http_v2_huff_encode_code_t  ngx_http_v2_huff_encode_table[256] =
{
    {0x00001ff8, 13}, {0x007fffd8, 23}, {0x0fffffe2, 28}, {0x0fffffe3, 28},
    {0x0fffffe4, 28}, {0x0fffffe5, 28}, {0x0fffffe6, 28}, {0x0fffffe7, 28},
    {0x0fffffe8, 28}, {0x00ffffea, 24}, {0x3ffffffc, 30}, {0x0fffffe9, 28},
    {0x0fffffea, 28}, {0x3ffffffd, 30}, {0x0fffffeb, 28}, {0x0fffffec, 28},
    {0x0fffffed, 28}, {0x0fffffee, 28}, {0x0fffffef, 28}, {0x0ffffff0, 28},
    {0x0ffffff1, 28}, {0x0ffffff2, 28}, {0x3ffffffe, 30}, {0x0ffffff3, 28},
    {0x0ffffff4, 28}, {0x0ffffff5, 28}, {0x0ffffff6, 28}, {0x0ffffff7, 28},
    {0x0ffffff8, 28}, {0x0ffffff9, 28}, {0x0ffffffa, 28}, {0x0ffffffb, 28},
    {0x00000014,  6}, {0x000003f8, 10}, {0x000003f9, 10}, {0x00000ffa, 12},
    {0x00001ff9, 13}, {0x00000015,  6}, {0x000000f8,  8}, {0x000007fa, 11},
    {0x000003fa, 10}, {0x000003fb, 10}, {0x000000f9,  8}, {0x000007fb, 11},
    {0x000000fa,  8}, {0x00000016,  6}, {0x00000017,  6}, {0x00000018,  6},
    {0x00000000,  5}, {0x00000001,  5}, {0x00000002,  5}, {0x00000019,  6},
    {0x0000001a,  6}, {0x0000001b,  6}, {0x0000001c,  6}, {0x0000001d,  6},
    {0x0000001e,  6}, {0x0000001f,  6}, {0x0000005c,  7}, {0x000000fb,  8},
    {0x00007ffc, 15}, {0x00000020,  6}, {0x00000ffb, 12}, {0x000003fc, 10},
    {0x00001ffa, 13}, {0x00000021,  6}, {0x0000005d,  7}, {0x0000005e,  7},
    {0x0000005f,  7}, {0x00000060,  7}, {0x00000061,  7}, {0x00000062,  7},
    {0x00000063,  7}, {0x00000064,  7}, {0x00000065,  7}, {0x00000066,  7},
    {0x00000067,  7}, {0x00000068,  7}, {0x00000069,  7}, {0x0000006a,  7},
    {0x0000006b,  7}, {0x0000006c,  7}, {0x0000006d,  7}, {0x0000006e,  7},
    {0x0000006f,  7}, {0x00000070,  7}, {0x00000071,  7}, {0x00000072,  7},
    {0x000000fc,  8}, {0x00000073,  7}, {0x000000fd,  8}, {0x00001ffb, 13},
    {0x0007fff0, 19}, {0x00001ffc, 13}, {0x00003ffc, 14}, {0x00000022,  6},
    {0x00007ffd, 15}, {0x00000003,  5}, {0x00000023,  6}, {0x00000004,  5},
    {0x00000024,  6}, {0x00000005,  5}, {0x00000025,  6}, {0x00000026,  6},
    {0x00000027,  6}, {0x00000006,  5}, {0x00000074,  7}, {0x00000075,  7},
    {0x00000028,  6}, {0x00000029,  6}, {0x0000002a,  6}, {0x00000007,  5},
    {0x0000002b,  6}, {0x00000076,  7}, {0x0000002c,  6}, {0x00000008,  5},
    {0x00000009,  5}, {0x0000002d,  6}, {0x00000077,  7}, {0x00000078,  7},
    {0x00000079,  7}, {0x0000007a,  7}, {0x0000007b,  7}, {0x00007ffe, 15},
    {0x000007fc, 11}, {0x00003ffd, 14}, {0x00001ffd, 13}, {0x0ffffffc, 28},
    {0x000fffe6, 20}, {0x003fffd2, 22}, {0x000fffe7, 20}, {0x000fffe8, 20},
    {0x003fffd3, 22}, {0x003fffd4, 22}, {0x003fffd5, 22}, {0x007fffd9, 23},
    {0x003fffd6, 22}, {0x007fffda, 23}, {0x007fffdb, 23}, {0x007fffdc, 23},
    {0x007fffdd, 23}, {0x007fffde, 23}, {0x00ffffeb, 24}, {0x007fffdf, 23},
    {0x00ffffec, 24}, {0x00ffffed, 24}, {0x003fffd7, 22}, {0x007fffe0, 23},
    {0x00ffffee, 24}, {0x007fffe1, 23}, {0x007fffe2, 23}, {0x007fffe3, 23},
    {0x007fffe4, 23}, {0x001fffdc, 21}, {0x003fffd8, 22}, {0x007fffe5, 23},
    {0x003fffd9, 22}, {0x007fffe6, 23}, {0x007fffe7, 23}, {0x00ffffef, 24},
    {0x003fffda, 22}, {0x001fffdd, 21}, {0x000fffe9, 20}, {0x003fffdb, 22},
    {0x003fffdc, 22}, {0x007fffe8, 23}, {0x007fffe9, 23}, {0x001fffde, 21},
    {0x007fffea, 23}, {0x003fffdd, 22}, {0x003fffde, 22}, {0x00fffff0, 24},
    {0x001fffdf, 21}, {0x003fffdf, 22}, {0x007fffeb, 23}, {0x007fffec, 23},
    {0x001fffe0, 21}, {0x001fffe1, 21}, {0x003fffe0, 22}, {0x001fffe2, 21},
    {0x007fffed, 23}, {0x003fffe1, 22}, {0x007fffee, 23}, {0x007fffef, 23},
    {0x000fffea, 20}, {0x003fffe2, 22}, {0x003fffe3, 22}, {0x003fffe4, 22},
    {0x007ffff0, 23}, {0x003fffe5, 22}, {0x003fffe6, 22}, {0x007ffff1, 23},
    {0x03ffffe0, 26}, {0x03ffffe1, 26}, {0x000fffeb, 20}, {0x0007fff1, 19},
    {0x003fffe7, 22}, {0x007ffff2, 23}, {0x003fffe8, 22}, {0x01ffffec, 25},
    {0x03ffffe2, 26}, {0x03ffffe3, 26}, {0x03ffffe4, 26}, {0x07ffffde, 27},
    {0x07ffffdf, 27}, {0x03ffffe5, 26}, {0x00fffff1, 24}, {0x01ffffed, 25},
    {0x0007fff2, 19}, {0x001fffe3, 21}, {0x03ffffe6, 26}, {0x07ffffe0, 27},
    {0x07ffffe1, 27}, {0x03ffffe7, 26}, {0x07ffffe2, 27}, {0x00fffff2, 24},
    {0x001fffe4, 21}, {0x001fffe5, 21}, {0x03ffffe8, 26}, {0x03ffffe9, 26},
    {0x0ffffffd, 28}, {0x07ffffe3, 27}, {0x07ffffe4, 27}, {0x07ffffe5, 27},
    {0x000fffec, 20}, {0x00fffff3, 24}, {0x000fffed, 20}, {0x001fffe6, 21},
    {0x003fffe9, 22}, {0x001fffe7, 21}, {0x001fffe8, 21}, {0x007ffff3, 23},
    {0x003fffea, 22}, {0x003fffeb, 22}, {0x01ffffee, 25}, {0x01ffffef, 25},
    {0x00fffff4, 24}, {0x00fffff5, 24}, {0x03ffffea, 26}, {0x007ffff4, 23},
    {0x03ffffeb, 26}, {0x07ffffe6, 27}, {0x03ffffec, 26}, {0x03ffffed, 26},
    {0x07ffffe7, 27}, {0x07ffffe8, 27}, {0x07ffffe9, 27}, {0x07ffffea, 27},
    {0x07ffffeb, 27}, {0x0ffffffe, 28}, {0x07ffffec, 27}, {0x07ffffed, 27},
    {0x07ffffee, 27}, {0x07ffffef, 27}, {0x07fffff0, 27}, {0x03ffffee, 26}
};


/* same as above, but embeds lowercase transformation */
static ngx_http_v2_huff_encode_code_t  ngx_http_v2_huff_encode_table_lc[256] =
{
    {0x00001ff8, 13}, {0x007fffd8, 23}, {0x0fffffe2, 28}, {0x0fffffe3, 28},
    {0x0fffffe4, 28}, {0x0fffffe5, 28}, {0x0fffffe6, 28}, {0x0fffffe7, 28},
    {0x0fffffe8, 28}, {0x00ffffea, 24}, {0x3ffffffc, 30}, {0x0fffffe9, 28},
    {0x0fffffea, 28}, {0x3ffffffd, 30}, {0x0fffffeb, 28}, {0x0fffffec, 28},
    {0x0fffffed, 28}, {0x0fffffee, 28}, {0x0fffffef, 28}, {0x0ffffff0, 28},
    {0x0ffffff1, 28}, {0x0ffffff2, 28}, {0x3ffffffe, 30}, {0x0ffffff3, 28},
    {0x0ffffff4, 28}, {0x0ffffff5, 28}, {0x0ffffff6, 28}, {0x0ffffff7, 28},
    {0x0ffffff8, 28}, {0x0ffffff9, 28}, {0x0ffffffa, 28}, {0x0ffffffb, 28},
    {0x00000014,  6}, {0x000003f8, 10}, {0x000003f9, 10}, {0x00000ffa, 12},
    {0x00001ff9, 13}, {0x00000015,  6}, {0x000000f8,  8}, {0x000007fa, 11},
    {0x000003fa, 10}, {0x000003fb, 10}, {0x000000f9,  8}, {0x000007fb, 11},
    {0x000000fa,  8}, {0x00000016,  6}, {0x00000017,  6}, {0x00000018,  6},
    {0x00000000,  5}, {0x00000001,  5}, {0x00000002,  5}, {0x00000019,  6},
    {0x0000001a,  6}, {0x0000001b,  6}, {0x0000001c,  6}, {0x0000001d,  6},
    {0x0000001e,  6}, {0x0000001f,  6}, {0x0000005c,  7}, {0x000000fb,  8},
    {0x00007ffc, 15}, {0x00000020,  6}, {0x00000ffb, 12}, {0x000003fc, 10},
    {0x00001ffa, 13}, {0x00000003,  5}, {0x00000023,  6}, {0x00000004,  5},
    {0x00000024,  6}, {0x00000005,  5}, {0x00000025,  6}, {0x00000026,  6},
    {0x00000027,  6}, {0x00000006,  5}, {0x00000074,  7}, {0x00000075,  7},
    {0x00000028,  6}, {0x00000029,  6}, {0x0000002a,  6}, {0x00000007,  5},
    {0x0000002b,  6}, {0x00000076,  7}, {0x0000002c,  6}, {0x00000008,  5},
    {0x00000009,  5}, {0x0000002d,  6}, {0x00000077,  7}, {0x00000078,  7},
    {0x00000079,  7}, {0x0000007a,  7}, {0x0000007b,  7}, {0x00001ffb, 13},
    {0x0007fff0, 19}, {0x00001ffc, 13}, {0x00003ffc, 14}, {0x00000022,  6},
    {0x00007ffd, 15}, {0x00000003,  5}, {0x00000023,  6}, {0x00000004,  5},
    {0x00000024,  6}, {0x00000005,  5}, {0x00000025,  6}, {0x00000026,  6},
    {0x00000027,  6}, {0x00000006,  5}, {0x00000074,  7}, {0x00000075,  7},
    {0x00000028,  6}, {0x00000029,  6}, {0x0000002a,  6}, {0x00000007,  5},
    {0x0000002b,  6}, {0x00000076,  7}, {0x0000002c,  6}, {0x00000008,  5},
    {0x00000009,  5}, {0x0000002d,  6}, {0x00000077,  7}, {0x00000078,  7},
    {0x00000079,  7}, {0x0000007a,  7}, {0x0000007b,  7}, {0x00007ffe, 15},
    {0x000007fc, 11}, {0x00003ffd, 14}, {0x00001ffd, 13}, {0x0ffffffc, 28},
    {0x000fffe6, 20}, {0x003fffd2, 22}, {0x000fffe7, 20}, {0x000fffe8, 20},
    {0x003fffd3, 22}, {0x003fffd4, 22}, {0x003fffd5, 22}, {0x007fffd9, 23},
    {0x003fffd6, 22}, {0x007fffda, 23}, {0x007fffdb, 23}, {0x007fffdc, 23},
    {0x007fffdd, 23}, {0x007fffde, 23}, {0x00ffffeb, 24}, {0x007fffdf, 23},
    {0x00ffffec, 24}, {0x00ffffed, 24}, {0x003fffd7, 22}, {0x007fffe0, 23},
    {0x00ffffee, 24}, {0x007fffe1, 23}, {0x007fffe2, 23}, {0x007fffe3, 23},
    {0x007fffe4, 23}, {0x001fffdc, 21}, {0x003fffd8, 22}, {0x007fffe5, 23},
    {0x003fffd9, 22}, {0x007fffe6, 23}, {0x007fffe7, 23}, {0x00ffffef, 24},
    {0x003fffda, 22}, {0x001fffdd, 21}, {0x000fffe9, 20}, {0x003fffdb, 22},
    {0x003fffdc, 22}, {0x007fffe8, 23}, {0x007fffe9, 23}, {0x001fffde, 21},
    {0x007fffea, 23}, {0x003fffdd, 22}, {0x003fffde, 22}, {0x00fffff0, 24},
    {0x001fffdf, 21}, {0x003fffdf, 22}, {0x007fffeb, 23}, {0x007fffec, 23},
    {0x001fffe0, 21}, {0x001fffe1, 21}, {0x003fffe0, 22}, {0x001fffe2, 21},
    {0x007fffed, 23}, {0x003fffe1, 22}, {0x007fffee, 23}, {0x007fffef, 23},
    {0x000fffea, 20}, {0x003fffe2, 22}, {0x003fffe3, 22}, {0x003fffe4, 22},
    {0x007ffff0, 23}, {0x003fffe5, 22}, {0x003fffe6, 22}, {0x007ffff1, 23},
    {0x03ffffe0, 26}, {0x03ffffe1, 26}, {0x000fffeb, 20}, {0x0007fff1, 19},
    {0x003fffe7, 22}, {0x007ffff2, 23}, {0x003fffe8, 22}, {0x01ffffec, 25},
    {0x03ffffe2, 26}, {0x03ffffe3, 26}, {0x03ffffe4, 26}, {0x07ffffde, 27},
    {0x07ffffdf, 27}, {0x03ffffe5, 26}, {0x00fffff1, 24}, {0x01ffffed, 25},
    {0x0007fff2, 19}, {0x001fffe3, 21}, {0x03ffffe6, 26}, {0x07ffffe0, 27},
    {0x07ffffe1, 27}, {0x03ffffe7, 26}, {0x07ffffe2, 27}, {0x00fffff2, 24},
    {0x001fffe4, 21}, {0x001fffe5, 21}, {0x03ffffe8, 26}, {0x03ffffe9, 26},
    {0x0ffffffd, 28}, {0x07ffffe3, 27}, {0x07ffffe4, 27}, {0x07ffffe5, 27},
    {0x000fffec, 20}, {0x00fffff3, 24}, {0x000fffed, 20}, {0x001fffe6, 21},
    {0x003fffe9, 22}, {0x001fffe7, 21}, {0x001fffe8, 21}, {0x007ffff3, 23},
    {0x003fffea, 22}, {0x003fffeb, 22}, {0x01ffffee, 25}, {0x01ffffef, 25},
    {0x00fffff4, 24}, {0x00fffff5, 24}, {0x03ffffea, 26}, {0x007ffff4, 23},
    {0x03ffffeb, 26}, {0x07ffffe6, 27}, {0x03ffffec, 26}, {0x03ffffed, 26},
    {0x07ffffe7, 27}, {0x07ffffe8, 27}, {0x07ffffe9, 27}, {0x07ffffea, 27},
    {0x07ffffeb, 27}, {0x0ffffffe, 28}, {0x07ffffec, 27}, {0x07ffffed, 27},
    {0x07ffffee, 27}, {0x07ffffef, 27}, {0x07fffff0, 27}, {0x03ffffee, 26}
};


#if (NGX_PTR_SIZE == 8)

#if (NGX_HAVE_LITTLE_ENDIAN)

#if (NGX_HAVE_GCC_BSWAP64)
#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    (*(uint64_t *) (dst) = __builtin_bswap64(buf))
#else
#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    ((dst)[0] = (u_char) ((buf) >> 56),                                       \
     (dst)[1] = (u_char) ((buf) >> 48),                                       \
     (dst)[2] = (u_char) ((buf) >> 40),                                       \
     (dst)[3] = (u_char) ((buf) >> 32),                                       \
     (dst)[4] = (u_char) ((buf) >> 24),                                       \
     (dst)[5] = (u_char) ((buf) >> 16),                                       \
     (dst)[6] = (u_char) ((buf) >> 8),                                        \
     (dst)[7] = (u_char)  (buf))
#endif

#else /* !NGX_HAVE_LITTLE_ENDIAN */
#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    (*(uint64_t *) (dst) = (buf))
#endif

#else /* NGX_PTR_SIZE == 4 */

#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    (*(uint32_t *) (dst) = htonl(buf))

#endif


size_t
ngx_http_v2_huff_encode(u_char *src, size_t len, u_char *dst, ngx_uint_t lower)
{
    u_char                          *end;
    size_t                           hlen;
    ngx_uint_t                       buf, pending, code;
    ngx_http_v2_huff_encode_code_t  *table, *next;

    table = lower ? ngx_http_v2_huff_encode_table_lc
                  : ngx_http_v2_huff_encode_table;
    hlen = 0;
    buf = 0;
    pending = 0;

    end = src + len;

    while (src != end) {
        next = &table[*src++];

        code = next->code;
        pending += next->len;

        /* accumulate bits */
        if (pending < sizeof(buf) * 8) {
            buf |= code << (sizeof(buf) * 8 - pending);
            continue;
        }

        if (hlen + sizeof(buf) >= len) {
            return 0;
        }

        pending -= sizeof(buf) * 8;

        buf |= code >> pending;

        ngx_http_v2_huff_encode_buf(&dst[hlen], buf);

        hlen += sizeof(buf);

        buf = pending ? code << (sizeof(buf) * 8 - pending) : 0;
    }

    if (pending == 0) {
        return hlen;
    }

    buf |= (ngx_uint_t) -1 >> pending;

    pending = ngx_align(pending, 8);

    if (hlen + pending / 8 >= len) {
        return 0;
    }

    buf >>= sizeof(buf) * 8 - pending;

    do {
        pending -= 8;
        dst[hlen++] = (u_char) (buf >> pending);
    } while (pending);

    return hlen;
}