Memcached: stricten header validation.
An invalid memcached reply that started with '\n' could cause
segmentation fault.
An invalid memcached reply "VALUE / 0 2\r?ok\r\nEND\r\n" was
considered as a valid response.
In addition, if memcached reports that the key was not found,
set u->headers_in.content_length_n to 0. This ensures that
ngx_http_memcached_filter() will not be called while previous
code relied on always intercepting 404. Initialization of
ctx->rest was moved to where it belongs.
diff --git a/src/http/modules/ngx_http_memcached_module.c b/src/http/modules/ngx_http_memcached_module.c
index 278b1ed..c36ad0f 100644
--- a/src/http/modules/ngx_http_memcached_module.c
+++ b/src/http/modules/ngx_http_memcached_module.c
@@ -197,7 +197,6 @@
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
- ctx->rest = NGX_HTTP_MEMCACHED_END;
ctx->request = r;
ngx_http_set_ctx(r, ctx, ngx_http_memcached_module);
@@ -309,10 +308,15 @@
found:
- *p = '\0';
-
- line.len = p - u->buffer.pos - 1;
line.data = u->buffer.pos;
+ line.len = p - u->buffer.pos;
+
+ if (line.len == 0 || *(p - 1) != CR) {
+ goto no_valid;
+ }
+
+ *p = '\0';
+ line.len--;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"memcached: \"%V\"", &line);
@@ -387,10 +391,9 @@
length:
start = p;
+ p = line.data + line.len;
- while (*p && *p++ != CR) { /* void */ }
-
- u->headers_in.content_length_n = ngx_atoof(start, p - start - 1);
+ u->headers_in.content_length_n = ngx_atoof(start, p - start);
if (u->headers_in.content_length_n == -1) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"memcached sent invalid length in response \"%V\" "
@@ -401,7 +404,7 @@
u->headers_in.status_n = 200;
u->state->status = 200;
- u->buffer.pos = p + 1;
+ u->buffer.pos = p + sizeof(CRLF) - 1;
return NGX_OK;
}
@@ -410,8 +413,10 @@
ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
"key: \"%V\" was not found by memcached", &ctx->key);
+ u->headers_in.content_length_n = 0;
u->headers_in.status_n = 404;
u->state->status = 404;
+ u->buffer.pos = p + sizeof("END" CRLF) - 1;
u->keepalive = 1;
return NGX_OK;
@@ -435,7 +440,10 @@
u = ctx->request->upstream;
- u->length += NGX_HTTP_MEMCACHED_END;
+ if (u->headers_in.status_n != 404) {
+ u->length += NGX_HTTP_MEMCACHED_END;
+ ctx->rest = NGX_HTTP_MEMCACHED_END;
+ }
return NGX_OK;
}
