Mercurial > hg > nginx

view src/http/v3/ngx_http_v3_encode.c @ 9112:d59277dd3d8c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
QUIC: fixed post-close use-after-free. Previously, ngx_quic_close_connection() could be called in a way that QUIC connection was accessed after the call. In most cases the connection is not closed right away, but close timeout is scheduled. However, it's not always the case. Also, if the close process started earlier for a different reason, calling ngx_quic_close_connection() may actually close the connection. The connection object should not be accessed after that. Now, when possible, return statement is added to eliminate post-close connection object access. In other places ngx_quic_close_connection() is substituted with posting close event. Also, the new way of closing connection in ngx_quic_stream_cleanup_handler() fixes another problem in this function. Previously it passed stream connection instead of QUIC connection to ngx_quic_close_connection(). This could result in incomplete connection shutdown. One consequence of that could be that QUIC streams were freed without shutting down their application contexts. This could result in another use-after-free. Found by Coverity (CID 1530402).
author Roman Arutyunyan <arut@nginx.com>
date Mon, 22 May 2023 15:59:42 +0400
parents 5c86189a1c1b
children
line wrap: on
line source


/*
 * Copyright (C) Roman Arutyunyan
 * Copyright (C) Nginx, Inc.
 */


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


uintptr_t
ngx_http_v3_encode_varlen_int(u_char *p, uint64_t value)
{
    if (value <= 63) {
        if (p == NULL) {
            return 1;
        }

        *p++ = value;
        return (uintptr_t) p;
    }

    if (value <= 16383) {
        if (p == NULL) {
            return 2;
        }

        *p++ = 0x40 | (value >> 8);
        *p++ = value;
        return (uintptr_t) p;
    }

    if (value <= 1073741823) {
        if (p == NULL) {
            return 4;
        }

        *p++ = 0x80 | (value >> 24);
        *p++ = (value >> 16);
        *p++ = (value >> 8);
        *p++ = value;
        return (uintptr_t) p;
    }

    if (p == NULL) {
        return 8;
    }

    *p++ = 0xc0 | (value >> 56);
    *p++ = (value >> 48);
    *p++ = (value >> 40);
    *p++ = (value >> 32);
    *p++ = (value >> 24);
    *p++ = (value >> 16);
    *p++ = (value >> 8);
    *p++ = value;
    return (uintptr_t) p;
}


uintptr_t
ngx_http_v3_encode_prefix_int(u_char *p, uint64_t value, ngx_uint_t prefix)
{
    ngx_uint_t  thresh, n;

    thresh = (1 << prefix) - 1;

    if (value < thresh) {
        if (p == NULL) {
            return 1;
        }

        *p++ |= value;
        return (uintptr_t) p;
    }

    value -= thresh;

    if (p == NULL) {
        for (n = 2; value >= 128; n++) {
            value >>= 7;
        }

        return n;
    }

    *p++ |= thresh;

    while (value >= 128) {
        *p++ = 0x80 | value;
        value >>= 7;
    }

    *p++ = value;

    return (uintptr_t) p;
}


uintptr_t
ngx_http_v3_encode_field_section_prefix(u_char *p, ngx_uint_t insert_count,
    ngx_uint_t sign, ngx_uint_t delta_base)
{
    if (p == NULL) {
        return ngx_http_v3_encode_prefix_int(NULL, insert_count, 8)
               + ngx_http_v3_encode_prefix_int(NULL, delta_base, 7);
    }

    *p = 0;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, insert_count, 8);

    *p = sign ? 0x80 : 0;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, delta_base, 7);

    return (uintptr_t) p;
}


uintptr_t
ngx_http_v3_encode_field_ri(u_char *p, ngx_uint_t dynamic, ngx_uint_t index)
{
    /* Indexed Field Line */

    if (p == NULL) {
        return ngx_http_v3_encode_prefix_int(NULL, index, 6);
    }

    *p = dynamic ? 0x80 : 0xc0;

    return ngx_http_v3_encode_prefix_int(p, index, 6);
}


uintptr_t
ngx_http_v3_encode_field_lri(u_char *p, ngx_uint_t dynamic, ngx_uint_t index,
    u_char *data, size_t len)
{
    size_t   hlen;
    u_char  *p1, *p2;

    /* Literal Field Line With Name Reference */

    if (p == NULL) {
        return ngx_http_v3_encode_prefix_int(NULL, index, 4)
               + ngx_http_v3_encode_prefix_int(NULL, len, 7)
               + len;
    }

    *p = dynamic ? 0x40 : 0x50;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, index, 4);

    p1 = p;
    *p = 0;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, len, 7);

    if (data) {
        p2 = p;
        hlen = ngx_http_huff_encode(data, len, p, 0);

        if (hlen) {
            p = p1;
            *p = 0x80;
            p = (u_char *) ngx_http_v3_encode_prefix_int(p, hlen, 7);

            if (p != p2) {
                ngx_memmove(p, p2, hlen);
            }

            p += hlen;

        } else {
            p = ngx_cpymem(p, data, len);
        }
    }

    return (uintptr_t) p;
}


uintptr_t
ngx_http_v3_encode_field_l(u_char *p, ngx_str_t *name, ngx_str_t *value)
{
    size_t   hlen;
    u_char  *p1, *p2;

    /* Literal Field Line With Literal Name */

    if (p == NULL) {
        return ngx_http_v3_encode_prefix_int(NULL, name->len, 3)
               + name->len
               + ngx_http_v3_encode_prefix_int(NULL, value->len, 7)
               + value->len;
    }

    p1 = p;
    *p = 0x20;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, name->len, 3);

    p2 = p;
    hlen = ngx_http_huff_encode(name->data, name->len, p, 1);

    if (hlen) {
        p = p1;
        *p = 0x28;
        p = (u_char *) ngx_http_v3_encode_prefix_int(p, hlen, 3);

        if (p != p2) {
            ngx_memmove(p, p2, hlen);
        }

        p += hlen;

    } else {
        ngx_strlow(p, name->data, name->len);
        p += name->len;
    }

    p1 = p;
    *p = 0;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, value->len, 7);

    p2 = p;
    hlen = ngx_http_huff_encode(value->data, value->len, p, 0);

    if (hlen) {
        p = p1;
        *p = 0x80;
        p = (u_char *) ngx_http_v3_encode_prefix_int(p, hlen, 7);

        if (p != p2) {
            ngx_memmove(p, p2, hlen);
        }

        p += hlen;

    } else {
        p = ngx_cpymem(p, value->data, value->len);
    }

    return (uintptr_t) p;
}


uintptr_t
ngx_http_v3_encode_field_pbi(u_char *p, ngx_uint_t index)
{
    /* Indexed Field Line With Post-Base Index */

    if (p == NULL) {
        return ngx_http_v3_encode_prefix_int(NULL, index, 4);
    }

    *p = 0x10;

    return ngx_http_v3_encode_prefix_int(p, index, 4);
}


uintptr_t
ngx_http_v3_encode_field_lpbi(u_char *p, ngx_uint_t index, u_char *data,
    size_t len)
{
    size_t   hlen;
    u_char  *p1, *p2;

    /* Literal Field Line With Post-Base Name Reference */

    if (p == NULL) {
        return ngx_http_v3_encode_prefix_int(NULL, index, 3)
               + ngx_http_v3_encode_prefix_int(NULL, len, 7)
               + len;
    }

    *p = 0;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, index, 3);

    p1 = p;
    *p = 0;
    p = (u_char *) ngx_http_v3_encode_prefix_int(p, len, 7);

    if (data) {
        p2 = p;
        hlen = ngx_http_huff_encode(data, len, p, 0);

        if (hlen) {
            p = p1;
            *p = 0x80;
            p = (u_char *) ngx_http_v3_encode_prefix_int(p, hlen, 7);

            if (p != p2) {
                ngx_memmove(p, p2, hlen);
            }

            p += hlen;

        } else {
            p = ngx_cpymem(p, data, len);
        }
    }

    return (uintptr_t) p;
}