Is there any one who would like to review this patch?

发自我的 iPhone

> 在 2018年3月8日，08:42，Haitao Lv <i@lvht.net> 写道：
>
> Sorry for disturbing. But I have to fix a buffer overflow bug.
> Here is the latest patch.
>
> Sorry. But please make your comments. Thank you.
>
>
> diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
> index 89cfe77a..c51d8ace 100644
> --- a/src/http/ngx_http_request.c
> +++ b/src/http/ngx_http_request.c
> @@ -17,6 +17,10 @@ static ssize_t ngx_http_read_request_header(ngx_http_request_t *r);
> static ngx_int_t ngx_http_alloc_large_header_buffer(ngx_http_request_t *r,
> ngx_uint_t request_line);
>
> +#if (NGX_HTTP_V2)
> +static void ngx_http_wait_v2_preface_handler(ngx_event_t *rev);
> +#endif
> +
> static ngx_int_t ngx_http_process_header_line(ngx_http_request_t *r,
> ngx_table_elt_t *h, ngx_uint_t offset);
> static ngx_int_t ngx_http_process_unique_header_line(ngx_http_request_t *r,
> @@ -321,7 +325,7 @@ ngx_http_init_connection(ngx_connection_t *c)
>
> #if (NGX_HTTP_V2)
> if (hc->addr_conf->http2) {
> - rev->handler = ngx_http_v2_init;
> + rev->handler = ngx_http_wait_v2_preface_handler;
> }
> #endif
>
> @@ -377,6 +381,110 @@ ngx_http_init_connection(ngx_connection_t *c)
> }
>
>
> +#if (NGX_HTTP_V2)
> +static void
> +ngx_http_wait_v2_preface_handler(ngx_event_t *rev)
> +{
> + size_t size;
> + ssize_t n;
> + ngx_buf_t *b;
> + ngx_connection_t *c;
> + static const u_char preface[] = "PRI";
> +
> + c = rev->data;
> + size = sizeof(preface) - 1;
> +
> + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
> + "http wait h2 preface handler");
> +
> + if (rev->timedout) {
> + ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + if (c->close) {
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + b = c->buffer;
> +
> + if (b == NULL) {
> + b = ngx_create_temp_buf(c->pool, size);
> + if (b == NULL) {
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + c->buffer = b;
> +
> + } else if (b->start == NULL) {
> +
> + b->start = ngx_palloc(c->pool, size);
> + if (b->start == NULL) {
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + b->pos = b->start;
> + b->last = b->start;
> + b->end = b->last + size;
> + }
> +
> + n = c->recv(c, b->last, b->end - b->last);
> +
> + if (n == NGX_AGAIN) {
> +
> + if (!rev->timer_set) {
> + ngx_add_timer(rev, c->listening->post_accept_timeout);
> + ngx_reusable_connection(c, 1);
> + }
> +
> + if (ngx_handle_read_event(rev, 0) != NGX_OK) {
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + /*
> + * We are trying to not hold c->buffer's memory for an idle connection.
> + */
> +
> + if (ngx_pfree(c->pool, b->start) == NGX_OK) {
> + b->start = NULL;
> + }
> +
> + return;
> + }
> +
> + if (n == NGX_ERROR) {
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + if (n == 0) {
> + ngx_log_error(NGX_LOG_INFO, c->log, 0,
> + "client closed connection");
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + b->last += n;
> +
> + if (b->last == b->end) {
> + /* b will be freed in ngx_http_v2_init/ngx_http_wait_request_handler */
> +
> + if (ngx_strncmp(b->start, preface, size) == 0) {
> + ngx_http_v2_init(rev);
> + } else {
> + rev->handler = ngx_http_wait_request_handler;
> + ngx_http_wait_request_handler(rev);
> + }
> + }
> +}
> +#endif
> +
> +
> static void
> ngx_http_wait_request_handler(ngx_event_t *rev)
> {
> @@ -430,6 +538,22 @@ ngx_http_wait_request_handler(ngx_event_t *rev)
> b->pos = b->start;
> b->last = b->start;
> b->end = b->last + size;
> + } else {
> +
> + p = ngx_palloc(c->pool, size);
> + if (p == NULL) {
> + ngx_http_close_connection(c);
> + return;
> + }
> +
> + n = b->last - b->start;
> + ngx_memcpy(p, b->start, n);
> + ngx_pfree(c->pool, b->start);
> +
> + b->start = p;
> + b->pos = b->start;
> + b->last = b->start + n;
> + b->end = b->last + size;
> }
>
> n = c->recv(c, b->last, size);
> diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
> index d9df0f90..e36bf382 100644
> --- a/src/http/v2/ngx_http_v2.c
> +++ b/src/http/v2/ngx_http_v2.c
> @@ -231,6 +231,8 @@ static ngx_http_v2_parse_header_t ngx_http_v2_parse_headers[] = {
> void
> ngx_http_v2_init(ngx_event_t *rev)
> {
> + size_t size;
> + ngx_buf_t *b;
> ngx_connection_t *c;
> ngx_pool_cleanup_t *cln;
> ngx_http_connection_t *hc;
> @@ -262,6 +264,23 @@ ngx_http_v2_init(ngx_event_t *rev)
> return;
> }
>
> + b = c->buffer;
> +
> + if (b != NULL) {
> + size = b->last - b->start;
> +
> + if (size > h2mcf->recv_buffer_size) {
> + size = h2mcf->recv_buffer_size;
> + }
> +
> + ngx_memcpy(h2mcf->recv_buffer, b->start, size);
> + h2c->state.buffer_used = size;
> +
> + ngx_pfree(c->pool, b->start);
> + ngx_pfree(c->pool, b);
> + c->buffer = NULL;
> + }
> +
> h2c->connection = c;
> h2c->http_connection = hc;
>
> @@ -381,13 +400,15 @@ ngx_http_v2_read_handler(ngx_event_t *rev)
> h2mcf = ngx_http_get_module_main_conf(h2c->http_connection->conf_ctx,
> ngx_http_v2_module);
>
> - available = h2mcf->recv_buffer_size - 2 * NGX_HTTP_V2_STATE_BUFFER_SIZE;
> + available = h2mcf->recv_buffer_size - h2c->state.buffer_used - 2 * NGX_HTTP_V2_STATE_BUFFER_SIZE;
>
> do {
> p = h2mcf->recv_buffer;
>
> - ngx_memcpy(p, h2c->state.buffer, NGX_HTTP_V2_STATE_BUFFER_SIZE);
> end = p + h2c->state.buffer_used;
> + if (h2c->state.buffer_used == 0) {
> + ngx_memcpy(p, h2c->state.buffer, NGX_HTTP_V2_STATE_BUFFER_SIZE);
> + }
>
> n = c->recv(c, end, available);
>
>
>
>
>> On Mar 6, 2018, at 03:14, Maxim Dounin <mdounin@mdounin.ru> wrote:
>>
>> Hello!
>>
>> On Mon, Mar 05, 2018 at 11:52:57PM +0800, Haitao Lv wrote:
>>
>> [...]
>>
>>>> Overall, the patch looks like a hack and introduces too much
>>>> complexity for this feature. While I understand the reasoning,
>>>> the proposed implementation cannot be accepted.
>>>
>>> Could you clarify that whether is this feature not accepted or this patch?
>>>
>>> If this feature is not needed, I will terminate this thread.
>>>
>>> If this patch only looks like a hack, would you like offer any advice to write
>>> code with good smell?
>>
>> We've previously discussed this with Valentin, and our position is
>> as follows:
>>
>> - The feature itself (autodetection between HTTP/2 and HTTP/1.x
>> protocols) might be usable, and we can consider adding it if
>> there will be a good and simple enough patch. (Moreover, we
>> think that this probably should be the default if "listen ...
>> http2" is configured - that is, no "http1" option.)
>>
>> - The patch suggested certainly doesn't meet the above criteria,
>> and it does not look like it can be fixed.
>>
>> We don't know if a good and simple enough implementation is at all
>> possible though. One of the possible approaches was already
>> proposed by Valentin (detect HTTP/2 or HTTP/1.x before starting
>> processing, may be similar to how we handle http-to-https
>> requests), but it's now immediately clear if it will work or not.
>> Sorry, but please don't expect any of us to provide further
>> guidance.
>>
>> --
>> Maxim Dounin
>> http://mdounin.ru/
>> _______________________________________________
>> nginx-devel mailing list
>> nginx-devel@nginx.org
>> http://mailman.nginx.org/mailman/listinfo/nginx-devel




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