From d9bb874591c63f2efbfc1c4c953934251c700e9f Mon Sep 17 00:00:00 2001 From: Xavier Del Campo Romero Date: Mon, 20 Mar 2023 03:32:00 +0100 Subject: [PATCH] Send response on quota exceeded So far, slcl would just close the connection with a client when the Content-Length of an incoming request exceeded the user quota, without any meaningful information given back to the user. Now, slcl responds with a HTML file with meaningful information about the error. Limitations: - While this commits has been successfully tested on ungoogled-chromium, LibreWolf (and I assume Firefox and any other derivates too) does not seem to receive the response from the server. - However, this issue only occurred during local testing, but not on remote instances. --- handler.c | 5 ++-- handler.h | 2 +- http.c | 33 +++++++++++++++----- http.h | 3 +- main.c | 14 +++++++-- page.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ page.h | 2 ++ 7 files changed, 136 insertions(+), 13 deletions(-) diff --git a/handler.c b/handler.c index 05650ca..22699f5 100644 --- a/handler.c +++ b/handler.c @@ -112,13 +112,14 @@ static int on_payload(const struct http_payload *const p, } static int on_length(const unsigned long long len, - const struct http_cookie *const c, void *const user) + const struct http_cookie *const c, struct http_response *const r, + void *const user) { struct client *const cl = user; struct handler *const h = cl->h; if (h->cfg.length) - return h->cfg.length(len, c, h->cfg.user); + return h->cfg.length(len, c, r, h->cfg.user); return 0; } diff --git a/handler.h b/handler.h index d851f65..38de97b 100644 --- a/handler.h +++ b/handler.h @@ -11,7 +11,7 @@ struct handler_cfg { const char *tmpdir; int (*length)(unsigned long long len, const struct http_cookie *c, - void *user); + struct http_response *r, void *user); void *user; }; diff --git a/http.c b/http.c index dae33d1..726e56a 100644 --- a/http.c +++ b/http.c @@ -85,7 +85,7 @@ struct http_ctx struct write_ctx { - bool pending; + bool pending, close; enum state state; struct http_response r; off_t n; @@ -372,6 +372,8 @@ static int write_header_cr_line(struct http_ctx *const h, bool *const close) return rw_error(res, close); else if ((w->n += res) >= d->len) { + const bool close_pending = w->close; + dynstr_free(d); if (w->r.n) @@ -384,6 +386,8 @@ static int write_header_cr_line(struct http_ctx *const h, bool *const close) fprintf(stderr, "%s: write_ctx_free failed\n", __func__); return -1; } + else if (close_pending) + *close = true; } return 0; @@ -394,17 +398,24 @@ static int write_body_mem(struct http_ctx *const h, bool *const close) struct write_ctx *const w = &h->wctx; const struct http_response *const r = &w->r; const size_t rem = r->n - w->n; - const int res = h->cfg.write((const char *)r->buf.ro + w->n, rem, + int res = h->cfg.write((const char *)r->buf.ro + w->n, rem, h->cfg.user); if (res <= 0) return rw_error(res, close); else if ((w->n += res) >= r->n) { + const bool close_pending = w->close; + if (h->version == HTTP_1_0) *close = true; - return write_ctx_free(w); + if ((res = write_ctx_free(w))) + fprintf(stderr, "%s: write_ctx_free failed\n", __func__); + else if (close_pending) + *close = true; + + return res; } return 0; @@ -425,16 +436,21 @@ static int write_body_file(struct http_ctx *const h, bool *const close) return -1; } - const int res = h->cfg.write(buf, rem, h->cfg.user); + int res = h->cfg.write(buf, rem, h->cfg.user); if (res <= 0) return rw_error(res, close); else if ((w->n += res) >= r->n) { + const bool close_pending = w->close; + if (h->version == HTTP_1_0) *close = true; - return write_ctx_free(w); + if ((res = write_ctx_free(w))) + fprintf(stderr, "%s: write_ctx_free failed\n", __func__); + else if (close_pending) + *close = true; } return 0; @@ -810,7 +826,7 @@ static int check_length(struct http_ctx *const h) .value = c->value }; - return h->cfg.length(c->post.len, &cookie, h->cfg.user); + return h->cfg.length(c->post.len, &cookie, &h->wctx.r, h->cfg.user); } static int header_cr_line(struct http_ctx *const h) @@ -834,7 +850,10 @@ static int header_cr_line(struct http_ctx *const h) const int res = check_length(h); if (res) - return res; + { + h->wctx.close = true; + return start_response(h); + } } c->state = BODY_LINE; diff --git a/http.h b/http.h index 33f42c6..ed0770f 100644 --- a/http.h +++ b/http.h @@ -45,6 +45,7 @@ struct http_payload X(UNAUTHORIZED, "Unauthorized", 401) \ X(FORBIDDEN, "Forbidden", 403) \ X(NOT_FOUND, "Not found", 404) \ + X(PAYLOAD_TOO_LARGE, "Payload too large", 413) \ X(INTERNAL_ERROR, "Internal Server Error", 500) struct http_response @@ -80,7 +81,7 @@ struct http_cfg int (*payload)(const struct http_payload *p, struct http_response *r, void *user); int (*length)(unsigned long long len, const struct http_cookie *c, - void *user); + struct http_response *r, void *user); const char *tmpdir; void *user; }; diff --git a/main.c b/main.c index 6e461b3..89edae3 100644 --- a/main.c +++ b/main.c @@ -610,7 +610,8 @@ static int check_quota(const struct auth *const a, const char *const username, } static int check_length(const unsigned long long len, - const struct http_cookie *const c, void *const user) + const struct http_cookie *const c, struct http_response *const r, + void *const user) { struct auth *const a = user; const char *const username = c->field; @@ -623,7 +624,16 @@ static int check_length(const unsigned long long len, return -1; } else if (has_quota) - return check_quota(a, username, len, quota); + { + int res = check_quota(a, username, len, quota); + + if (res < 0) + fprintf(stderr, "%s: check_quota failed\n", __func__); + else if (res > 0 && page_quota_exceeded(r, len, quota) < 0) + return -1; + + return res; + } return 0; } diff --git a/page.c b/page.c index 17adb8a..5cbb0a7 100644 --- a/page.c +++ b/page.c @@ -1311,3 +1311,93 @@ end: return ret; } + +int page_quota_exceeded(struct http_response *const r, + const unsigned long long len, const unsigned long long quota) +{ + int ret = -1; + struct dynstr msg, out; + char q[sizeof MAXSIZEFMT], l[sizeof q]; + struct html_node *const html = html_node_alloc("html"), + *head, *body; + + dynstr_init(&msg); + dynstr_init(&out); + + if (!html) + { + fprintf(stderr, "%s: html_node_alloc failed\n", __func__); + goto end; + } + else if (!(head = html_node_add_child(html, "head"))) + { + fprintf(stderr, "%s: html_node_add_child head failed\n", __func__); + goto end; + } + else if (!(body = html_node_add_child(html, "body"))) + { + fprintf(stderr, "%s: html_node_add_child body failed\n", __func__); + goto end; + } + else if (common_head(head, NULL)) + { + fprintf(stderr, "%s: common_head failed\n", __func__); + goto end; + } + else if (size_units(quota, q, sizeof q)) + { + fprintf(stderr, "%s: size_units quota failed\n", __func__); + goto end; + } + else if (size_units(len, l, sizeof l)) + { + fprintf(stderr, "%s: size_units len failed\n", __func__); + goto end; + } + else if (dynstr_append(&msg, "Maximum quota exceeded: %s " + "(requested size: %s)", q, l)) + { + fprintf(stderr, "%s: dynstr_append msg failed\n", __func__); + goto end; + } + else if (html_node_set_value(body, msg.str)) + { + fprintf(stderr, "%s: html_node_set_value msg failed\n", __func__); + goto end; + } + else if (dynstr_append(&out, DOCTYPE_TAG)) + { + fprintf(stderr, "%s: dynstr_prepend failed\n", __func__); + goto end; + } + else if (html_serialize(html, &out)) + { + fprintf(stderr, "%s: html_serialize failed\n", __func__); + goto end; + } + + *r = (const struct http_response) + { + .status = HTTP_STATUS_PAYLOAD_TOO_LARGE, + .buf.rw = out.str, + .n = out.len, + .free = free + }; + + if (http_response_add_header(r, "Content-Type", "text/html")) + { + fprintf(stderr, "%s: http_response_add_header failed\n", __func__); + goto end; + } + + ret = 0; + +end: + html_node_free(html); + dynstr_free(&msg); + + if (ret) + dynstr_free(&out); + + return ret; +} diff --git a/page.h b/page.h index 9df1eea..094a21e 100644 --- a/page.h +++ b/page.h @@ -17,5 +17,7 @@ int page_resource(struct http_response *r, const char *dir, const char *root, const char *res, const struct page_quota *q); int page_public(struct http_response *r, const char *res); int page_share(struct http_response *r, const char *path); +int page_quota_exceeded(struct http_response *r, unsigned long long len, + unsigned long long quota); #endif /* PAGE_H */