From 1f9427e1d9672b93577aea4c9d5a63575ee0b525 Mon Sep 17 00:00:00 2001 From: Christian Grothoff Date: Sat, 6 May 2023 19:43:17 +0200 Subject: [PATCH] add convenience function for content-length limiation --- contrib/gana | 2 +- src/exchange/taler-exchange-httpd.c | 29 +------------- src/include/taler_mhd_lib.h | 59 +++++++++++++++++++++++++---- src/mhd/mhd_parsing.c | 42 ++++++++++++++++++++ 4 files changed, 96 insertions(+), 36 deletions(-) diff --git a/contrib/gana b/contrib/gana index 85736484c..4654d82b1 160000 --- a/contrib/gana +++ b/contrib/gana @@ -1 +1 @@ -Subproject commit 85736484cb0da26aded705ebb1e944e8bb1b8504 +Subproject commit 4654d82b143cd69dfe7a7bf2f816f6f91f6052e2 diff --git a/src/exchange/taler-exchange-httpd.c b/src/exchange/taler-exchange-httpd.c index ac3eae272..97cf54c86 100644 --- a/src/exchange/taler-exchange-httpd.c +++ b/src/exchange/taler-exchange-httpd.c @@ -1617,33 +1617,8 @@ handle_mhd_request (void *cls, if (0 == strcasecmp (method, MHD_HTTP_METHOD_POST)) { - const char *cl; - - /* Maybe check for maximum upload size - and refuse requests if they are just too big. */ - cl = MHD_lookup_connection_value (connection, - MHD_HEADER_KIND, - MHD_HTTP_HEADER_CONTENT_LENGTH); - if (NULL != cl) - { - unsigned long long cv; - char dummy; - - if (1 != sscanf (cl, - "%llu%c", - &cv, - &dummy)) - { - /* Not valid HTTP request, just close connection. */ - GNUNET_break_op (0); - return MHD_NO; - } - if (cv > TALER_MHD_REQUEST_BUFFER_MAX) - { - GNUNET_break_op (0); - return TALER_MHD_reply_request_too_large (connection); - } - } + TALER_MHD_check_content_length (connection, + TALER_MHD_REQUEST_BUFFER_MAX); } } diff --git a/src/include/taler_mhd_lib.h b/src/include/taler_mhd_lib.h index 9c7c06d9a..e4aa916e7 100644 --- a/src/include/taler_mhd_lib.h +++ b/src/include/taler_mhd_lib.h @@ -596,14 +596,14 @@ TALER_MHD_parse_request_header_data (struct MHD_Connection *connection, bool p; \ switch (TALER_MHD_parse_request_header_data (connection, name, \ val, sizeof (*val), &p)) \ - { \ - case GNUNET_SYSERR: \ - GNUNET_break (0); \ - return MHD_NO; \ - case GNUNET_NO: \ - GNUNET_break_op (0); \ - return MHD_YES; \ - case GNUNET_OK: \ + { \ + case GNUNET_SYSERR: \ + GNUNET_break (0); \ + return MHD_NO; \ + case GNUNET_NO: \ + GNUNET_break_op (0); \ + return MHD_YES; \ + case GNUNET_OK: \ if (required & (! p)) \ return TALER_MHD_reply_with_error ( \ connection, \ @@ -634,6 +634,49 @@ TALER_MHD_parse_request_header_data (struct MHD_Connection *connection, } while (0) +/** + * Check that the 'Content-Length' header is giving + * a length below @a max_len. If not, return an + * appropriate error response and return the + * correct #MHD_YES/#MHD_NO value from this function. + * + * @param connection the MHD connection + * @param max_len maximum allowed content length + * @return + * #GNUNET_YES if the the argument is present + * #GNUNET_NO if the argument is absent or malformed + * #GNUNET_SYSERR on internal error (error response could not be sent) + */ +enum GNUNET_GenericReturnValue +TALER_MHD_check_content_length_ (struct MHD_Connection *connection, + unsigned long long max_len); + + +/** + * Check that the 'Content-Length' header is giving + * a length below @a max_len. If not, return an + * appropriate error response and return the + * correct #MHD_YES/#MHD_NO value from this function. + * + * @param connection the MHD connection + * @param max_len maximum allowed content length + */ +#define TALER_MHD_check_content_length(connection,max_len) \ + do { \ + switch (TALER_MHD_check_content_length_ (connection, max_len)) \ + { \ + case GNUNET_SYSERR: \ + GNUNET_break (0); \ + return MHD_NO; \ + case GNUNET_NO: \ + GNUNET_break_op (0); \ + return MHD_YES; \ + case GNUNET_OK: \ + break; \ + } \ + } while (0) + + /** * Parse the configuration to determine on which port * or UNIX domain path we should run an HTTP service. diff --git a/src/mhd/mhd_parsing.c b/src/mhd/mhd_parsing.c index e76450831..b047df7d3 100644 --- a/src/mhd/mhd_parsing.c +++ b/src/mhd/mhd_parsing.c @@ -350,4 +350,46 @@ TALER_MHD_parse_json_array (struct MHD_Connection *connection, } +enum GNUNET_GenericReturnValue +TALER_MHD_check_content_length_ (struct MHD_Connection *connection, + unsigned long long max_len) +{ + const char *cl; + unsigned long long cv; + char dummy; + + /* Maybe check for maximum upload size + and refuse requests if they are just too big. */ + cl = MHD_lookup_connection_value (connection, + MHD_HEADER_KIND, + MHD_HTTP_HEADER_CONTENT_LENGTH); + if (NULL == cl) + return GNUNET_OK; + if (1 != sscanf (cl, + "%llu%c", + &cv, + &dummy)) + { + /* Not valid HTTP request, just close connection. */ + GNUNET_break_op (0); + return (MHD_YES == + TALER_MHD_reply_with_error (connection, + MHD_HTTP_BAD_REQUEST, + TALER_EC_GENERIC_PARAMETER_MALFORMED, + MHD_HTTP_HEADER_CONTENT_LENGTH)) + ? GNUNET_NO + : GNUNET_SYSERR; + } + if (cv > TALER_MHD_REQUEST_BUFFER_MAX) + { + GNUNET_break_op (0); + return (MHD_YES == + TALER_MHD_reply_request_too_large (connection)) + ? GNUNET_NO + : GNUNET_SYSERR; + } + return GNUNET_OK; +} + + /* end of mhd_parsing.c */