diff options
Diffstat (limited to 'debian/patches/BUG-MINOR-h1-do-not-accept-as-part-of-the-URI-compon.patch')
| -rw-r--r-- | debian/patches/BUG-MINOR-h1-do-not-accept-as-part-of-the-URI-compon.patch | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/debian/patches/BUG-MINOR-h1-do-not-accept-as-part-of-the-URI-compon.patch b/debian/patches/BUG-MINOR-h1-do-not-accept-as-part-of-the-URI-compon.patch new file mode 100644 index 0000000..02d1e74 --- /dev/null +++ b/debian/patches/BUG-MINOR-h1-do-not-accept-as-part-of-the-URI-compon.patch @@ -0,0 +1,118 @@ +From: Willy Tarreau <w@1wt.eu> +Date: Tue, 8 Aug 2023 16:17:22 +0200 +Subject: BUG/MINOR: h1: do not accept '#' as part of the URI component +Origin: https://git.haproxy.org/?p=haproxy-2.6.git;a=commit;h=832b672eee54866c7a42a1d46078cc9ae0d544d9 +Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2023-45539 + +Seth Manesse and Paul Plasil reported that the "path" sample fetch +function incorrectly accepts '#' as part of the path component. This +can in some cases lead to misrouted requests for rules that would apply +on the suffix: + + use_backend static if { path_end .png .jpg .gif .css .js } + +Note that this behavior can be selectively configured using +"normalize-uri fragment-encode" and "normalize-uri fragment-strip". + +The problem is that while the RFC says that this '#' must never be +emitted, as often it doesn't suggest how servers should handle it. A +diminishing number of servers still do accept it and trim it silently, +while others are rejecting it, as indicated in the conversation below +with other implementers: + + https://lists.w3.org/Archives/Public/ietf-http-wg/2023JulSep/0070.html + +Looking at logs from publicly exposed servers, such requests appear at +a rate of roughly 1 per million and only come from attacks or poorly +written web crawlers incorrectly following links found on various pages. + +Thus it looks like the best solution to this problem is to simply reject +such ambiguous requests by default, and include this in the list of +controls that can be disabled using "option accept-invalid-http-request". + +We're already rejecting URIs containing any control char anyway, so we +should also reject '#'. + +In the H1 parser for the H1_MSG_RQURI state, there is an accelerated +parser for bytes 0x21..0x7e that has been tightened to 0x24..0x7e (it +should not impact perf since 0x21..0x23 are not supposed to appear in +a URI anyway). This way '#' falls through the fine-grained filter and +we can add the special case for it also conditionned by a check on the +proxy's option "accept-invalid-http-request", with no overhead for the +vast majority of valid URIs. Here this information is available through +h1m->err_pos that's set to -2 when the option is here (so we don't need +to change the API to expose the proxy). Example with a trivial GET +through netcat: + + [08/Aug/2023:16:16:52.651] frontend layer1 (#2): invalid request + backend <NONE> (#-1), server <NONE> (#-1), event #0, src 127.0.0.1:50812 + buffer starts at 0 (including 0 out), 16361 free, + len 23, wraps at 16336, error at position 7 + H1 connection flags 0x00000000, H1 stream flags 0x00000810 + H1 msg state MSG_RQURI(4), H1 msg flags 0x00001400 + H1 chunk len 0 bytes, H1 body len 0 bytes : + + 00000 GET /aa#bb HTTP/1.0\r\n + 00021 \r\n + +This should be progressively backported to all stable versions along with +the following patch: + + REGTESTS: http-rules: add accept-invalid-http-request for normalize-uri tests + +Similar fixes for h2 and h3 will come in followup patches. + +Thanks to Seth Manesse and Paul Plasil for reporting this problem with +detailed explanations. + +(cherry picked from commit 2eab6d354322932cfec2ed54de261e4347eca9a6) +Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com> +(cherry picked from commit 9bf75c8e22a8f2537f27c557854a8803087046d0) +Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com> +(cherry picked from commit 9facd01c9ac85fe9bcb331594b80fa08e7406552) +Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com> +--- + src/h1.c | 15 +++++++++++---- + 1 file changed, 11 insertions(+), 4 deletions(-) + +diff --git a/src/h1.c b/src/h1.c +index 126f23cc7376..92ec96bfe19e 100644 +--- a/src/h1.c ++++ b/src/h1.c +@@ -565,13 +565,13 @@ int h1_headers_to_hdr_list(char *start, const char *stop, + case H1_MSG_RQURI: + http_msg_rquri: + #ifdef HA_UNALIGNED_LE +- /* speedup: skip bytes not between 0x21 and 0x7e inclusive */ ++ /* speedup: skip bytes not between 0x24 and 0x7e inclusive */ + while (ptr <= end - sizeof(int)) { +- int x = *(int *)ptr - 0x21212121; ++ int x = *(int *)ptr - 0x24242424; + if (x & 0x80808080) + break; + +- x -= 0x5e5e5e5e; ++ x -= 0x5b5b5b5b; + if (!(x & 0x80808080)) + break; + +@@ -583,8 +583,15 @@ int h1_headers_to_hdr_list(char *start, const char *stop, + goto http_msg_ood; + } + http_msg_rquri2: +- if (likely((unsigned char)(*ptr - 33) <= 93)) /* 33 to 126 included */ ++ if (likely((unsigned char)(*ptr - 33) <= 93)) { /* 33 to 126 included */ ++ if (*ptr == '#') { ++ if (h1m->err_pos < -1) /* PR_O2_REQBUG_OK not set */ ++ goto invalid_char; ++ if (h1m->err_pos == -1) /* PR_O2_REQBUG_OK set: just log */ ++ h1m->err_pos = ptr - start + skip; ++ } + EAT_AND_JUMP_OR_RETURN(ptr, end, http_msg_rquri2, http_msg_ood, state, H1_MSG_RQURI); ++ } + + if (likely(HTTP_IS_SPHT(*ptr))) { + sl.rq.u.len = ptr - sl.rq.u.ptr; +-- +2.43.0 + |