diff options
| author | Xavier Del Campo Romero <xavi.dcr@tutanota.com> | 2024-08-26 01:10:16 +0200 |
|---|---|---|
| committer | Rodrigo Arias Mallo <rodarima@gmail.com> | 2024-09-02 00:21:23 +0200 |
| commit | 38d1620529866dbf638c6fd8a3e8e438b3c6a43c (patch) | |
| tree | ea5e7cda52114c67640636471fafaaf05cbb572d | |
| parent | 8a360e32ac3136494a494379a6dbbacef6f95da2 (diff) | |
Avoid searching for boundary in file content
Making the boundary string very unlikely to collide with the file to
upload allows Dillo to assume it would never be found and avoids the
expensive memmem() check.
Even if major implementations tend to add several '-' characters to
multipart/form-data boundaries, this is not enforced by RFC 2046, so it
can be increase to 70 random characters.
See: https://lists.mailman3.com/hyperkitty/list/dillo-dev@mailman3.com/thread/VUB5PIOPJZ2VTCVGQPBZMGOYEISTXCFX/
| -rw-r--r-- | src/dialog.cc | 1 | ||||
| -rw-r--r-- | src/form.cc | 30 |
2 files changed, 21 insertions, 10 deletions
diff --git a/src/dialog.cc b/src/dialog.cc index ac007315..0137472b 100644 --- a/src/dialog.cc +++ b/src/dialog.cc @@ -14,6 +14,7 @@ */ #include <math.h> // for rint() +#include <string.h> #include <FL/fl_ask.H> #include <FL/Fl_Window.H> diff --git a/src/form.cc b/src/form.cc index 93bd4864..6e81edf6 100644 --- a/src/form.cc +++ b/src/form.cc @@ -1246,6 +1246,24 @@ Dstr *DilloHtmlForm::buildQueryData(DilloHtmlInput *active_submit) return DataStr; } +static void generate_boundary(Dstr *boundary) +{ + for (int i = 0; i < 70; i++) { + /* Extracted from RFC 2046, section 5.1.1. */ + static const char set[] = "abcdefghijklmnopqrstuvwxyz" + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "0123456789" + "'()+_,-./:=? "; + char s[sizeof " "] = {0}; + + do { + *s = rand(); + } while (!strspn(s, set)); + + dStr_append(boundary, s); + } +} + /** * Generate a boundary string for use in separating the parts of a * multipart/form-data submission. @@ -1253,7 +1271,6 @@ Dstr *DilloHtmlForm::buildQueryData(DilloHtmlInput *active_submit) char *DilloHtmlForm::makeMultipartBoundary(iconv_t char_encoder, DilloHtmlInput *active_submit) { - const int max_tries = 10; Dlist *values = dList_new(5); Dstr *DataStr = dStr_new(""); Dstr *boundary = dStr_new(""); @@ -1294,15 +1311,8 @@ char *DilloHtmlForm::makeMultipartBoundary(iconv_t char_encoder, } } - /* generate a boundary that is not contained within the data */ - for (int i = 0; i < max_tries && !ret; i++) { - // Firefox-style boundary - dStr_sprintf(boundary, "---------------------------%d%d%d", - rand(), rand(), rand()); - dStr_truncate(boundary, 70); - if (dStr_memmem(DataStr, boundary) == NULL) - ret = boundary->str; - } + generate_boundary(boundary); + ret = boundary->str; dList_free(values); dStr_free(DataStr, 1); dStr_free(boundary, (ret == NULL)); |