mod_proxy_fcgi: Support Dynamic Buffering for Large FastCGI Headers #522
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notroj
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Mar 11, 2025
modules/proxy/mod_proxy_fcgi.c
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| @@ -593,6 +594,72 @@ static int handle_headers(request_rec *r, int *state, | |||
| return 0; | |||
| } | |||
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| /** | |||
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This part should be added to the varbuf API in server/util.c or else the existing ap_varbuf_* should be used, IMO.
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sound reasonable move it to server/util.c
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Done. Please @notroj do another pass
modules/proxy/mod_proxy_fcgi.c
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| @@ -640,6 +707,10 @@ static apr_status_t dispatch(proxy_conn_rec *conn, proxy_dir_conf *conf, | |||
| ib = apr_brigade_create(r->pool, c->bucket_alloc); | |||
| ob = apr_brigade_create(r->pool, c->bucket_alloc); | |||
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| /* Create our dynamic header buffer for large headers */ | |||
| ap_varbuf *header_vb = NULL; | |||
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Declaration should be at the top of the function, this is causing the CI failures.
arturobernalg
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This patch fixes Bug 64919 by replacing the fixed 8192‐byte header buffer with a dynamically resizable buffer that can handle arbitrarily long headers. It also adds a trimming step to remove any leading whitespace from the header data before parsing, ensuring that FastCGI responses are correctly interpreted.
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This pull request implements a dynamic header buffer in mod_proxy_fcgi to resolve Bug 64919. Previously, mod_proxy_fcgi used a fixed 8192-byte buffer to parse FastCGI headers, which caused failures when PHP-FPM (or similar backends) generated headers exceeding that size. With this patch, a dynamically resizable buffer is used so that arbitrarily large headers are handled gracefully.