From: Willy Tarreau Date: Tue, 8 Aug 2023 15:40:49 +0200 Subject: BUG/MINOR: h2: reject more chars from the :path pseudo header Origin: https://git.haproxy.org/?p=haproxy-2.6.git;a=commit;h=c8e07f2fd8b5462527f102f7145d6027c0d041da This is the h2 version of this previous fix: BUG/MINOR: h1: do not accept '#' as part of the URI component In addition to the current NUL/CR/LF, this will also reject all other control chars, the space and '#' from the :path pseudo-header, to avoid taking the '#' for a part of the path. It's still possible to fall back to the previous behavior using "option accept-invalid-http-request". This patch modifies the request parser to change the ":path" pseudo header validation function with a new one that rejects 0x00-0x1F (control chars), space and '#'. This way such chars will be dropped early in the chain, and the search for '#' doesn't incur a second pass over the header's value. This should be progressively backported to stable versions, along with the following commits it relies on: REGTESTS: http-rules: add accept-invalid-http-request for normalize-uri tests REORG: http: move has_forbidden_char() from h2.c to http.h MINOR: ist: add new function ist_find_range() to find a character range MINOR: http: add new function http_path_has_forbidden_char() MINOR: h2: pass accept-invalid-http-request down the request parser (cherry picked from commit b3119d4fb4588087e2483a80b01d322683719e29) Signed-off-by: Amaury Denoyelle (cherry picked from commit 462a8600ce9e478573a957e046b446a7dcffd286) Signed-off-by: Amaury Denoyelle (cherry picked from commit 648e59e30723b8fd4e71aab02cb679f6ea7446e7) Signed-off-by: Amaury Denoyelle --- src/h2.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/src/h2.c b/src/h2.c index cf42b7a5610e..67a443661c3e 100644 --- a/src/h2.c +++ b/src/h2.c @@ -337,11 +337,18 @@ int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *ms } /* RFC7540#10.3: intermediaries forwarding to HTTP/1 must take care of - * rejecting NUL, CR and LF characters. + * rejecting NUL, CR and LF characters. For :path we reject all CTL + * chars, spaces, and '#'. */ - ctl = ist_find_ctl(list[idx].v); - if (unlikely(ctl) && http_header_has_forbidden_char(list[idx].v, ctl)) - goto fail; + if (phdr == H2_PHDR_IDX_PATH && !relaxed) { + ctl = ist_find_range(list[idx].v, 0, '#'); + if (unlikely(ctl) && http_path_has_forbidden_char(list[idx].v, ctl)) + goto fail; + } else { + ctl = ist_find_ctl(list[idx].v); + if (unlikely(ctl) && http_header_has_forbidden_char(list[idx].v, ctl)) + goto fail; + } if (phdr > 0 && phdr < H2_PHDR_NUM_ENTRIES) { /* insert a pseudo header by its index (in phdr) and value (in value) */ -- 2.43.0