parent
760348d361
commit
561455141a
@ -0,0 +1,119 @@
|
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From e5a741f94977840c58775b38f8ed830207f7e4d0 Mon Sep 17 00:00:00 2001
|
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From: Willy Tarreau <w@1wt.eu>
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Date: Tue, 8 Aug 2023 16:17:22 +0200
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Subject: [PATCH] BUG/MINOR: h1: do not accept '#' as part of the URI component
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|
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Seth Manesse and Paul Plasil reported that the "path" sample fetch
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function incorrectly accepts '#' as part of the path component. This
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can in some cases lead to misrouted requests for rules that would apply
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on the suffix:
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use_backend static if { path_end .png .jpg .gif .css .js }
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Note that this behavior can be selectively configured using
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"normalize-uri fragment-encode" and "normalize-uri fragment-strip".
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The problem is that while the RFC says that this '#' must never be
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emitted, as often it doesn't suggest how servers should handle it. A
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diminishing number of servers still do accept it and trim it silently,
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while others are rejecting it, as indicated in the conversation below
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with other implementers:
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https://lists.w3.org/Archives/Public/ietf-http-wg/2023JulSep/0070.html
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Looking at logs from publicly exposed servers, such requests appear at
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a rate of roughly 1 per million and only come from attacks or poorly
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written web crawlers incorrectly following links found on various pages.
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Thus it looks like the best solution to this problem is to simply reject
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such ambiguous requests by default, and include this in the list of
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controls that can be disabled using "option accept-invalid-http-request".
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We're already rejecting URIs containing any control char anyway, so we
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should also reject '#'.
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In the H1 parser for the H1_MSG_RQURI state, there is an accelerated
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parser for bytes 0x21..0x7e that has been tightened to 0x24..0x7e (it
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should not impact perf since 0x21..0x23 are not supposed to appear in
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a URI anyway). This way '#' falls through the fine-grained filter and
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we can add the special case for it also conditionned by a check on the
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proxy's option "accept-invalid-http-request", with no overhead for the
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vast majority of valid URIs. Here this information is available through
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h1m->err_pos that's set to -2 when the option is here (so we don't need
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to change the API to expose the proxy). Example with a trivial GET
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through netcat:
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[08/Aug/2023:16:16:52.651] frontend layer1 (#2): invalid request
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backend <NONE> (#-1), server <NONE> (#-1), event #0, src 127.0.0.1:50812
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buffer starts at 0 (including 0 out), 16361 free,
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len 23, wraps at 16336, error at position 7
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H1 connection flags 0x00000000, H1 stream flags 0x00000810
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H1 msg state MSG_RQURI(4), H1 msg flags 0x00001400
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H1 chunk len 0 bytes, H1 body len 0 bytes :
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00000 GET /aa#bb HTTP/1.0\r\n
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00021 \r\n
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This should be progressively backported to all stable versions along with
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the following patch:
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REGTESTS: http-rules: add accept-invalid-http-request for normalize-uri tests
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Similar fixes for h2 and h3 will come in followup patches.
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Thanks to Seth Manesse and Paul Plasil for reporting this problem with
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detailed explanations.
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(cherry picked from commit 2eab6d354322932cfec2ed54de261e4347eca9a6)
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Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
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(cherry picked from commit 9bf75c8e22a8f2537f27c557854a8803087046d0)
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Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
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(cherry picked from commit 9facd01c9ac85fe9bcb331594b80fa08e7406552)
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Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
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(cherry picked from commit 832b672eee54866c7a42a1d46078cc9ae0d544d9)
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Signed-off-by: Willy Tarreau <w@1wt.eu>
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---
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src/h1.c | 15 +++++++++++----
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1 file changed, 11 insertions(+), 4 deletions(-)
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diff --git a/src/h1.c b/src/h1.c
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index eeda311b7..91d3dc47a 100644
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--- a/src/h1.c
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+++ b/src/h1.c
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@@ -480,13 +480,13 @@ int h1_headers_to_hdr_list(char *start, const char *stop,
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case H1_MSG_RQURI:
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http_msg_rquri:
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#ifdef HA_UNALIGNED_LE
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- /* speedup: skip bytes not between 0x21 and 0x7e inclusive */
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+ /* speedup: skip bytes not between 0x24 and 0x7e inclusive */
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while (ptr <= end - sizeof(int)) {
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- int x = *(int *)ptr - 0x21212121;
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+ int x = *(int *)ptr - 0x24242424;
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if (x & 0x80808080)
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break;
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- x -= 0x5e5e5e5e;
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+ x -= 0x5b5b5b5b;
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if (!(x & 0x80808080))
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break;
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@@ -498,8 +498,15 @@ int h1_headers_to_hdr_list(char *start, const char *stop,
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goto http_msg_ood;
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}
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http_msg_rquri2:
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- if (likely((unsigned char)(*ptr - 33) <= 93)) /* 33 to 126 included */
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+ if (likely((unsigned char)(*ptr - 33) <= 93)) { /* 33 to 126 included */
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+ if (*ptr == '#') {
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+ if (h1m->err_pos < -1) /* PR_O2_REQBUG_OK not set */
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+ goto invalid_char;
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+ if (h1m->err_pos == -1) /* PR_O2_REQBUG_OK set: just log */
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+ h1m->err_pos = ptr - start + skip;
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+ }
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EAT_AND_JUMP_OR_RETURN(ptr, end, http_msg_rquri2, http_msg_ood, state, H1_MSG_RQURI);
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+ }
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if (likely(HTTP_IS_SPHT(*ptr))) {
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sl.rq.u.len = ptr - sl.rq.u.ptr;
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--
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2.43.0
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|
@ -0,0 +1,76 @@
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From f86e994f5fb5851cd6e4f7f6b366e37765014b9f Mon Sep 17 00:00:00 2001
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From: Willy Tarreau <w@1wt.eu>
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Date: Tue, 8 Aug 2023 15:38:28 +0200
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Subject: [PATCH] MINOR: h2: pass accept-invalid-http-request down the request
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parser
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We're adding a new argument "relaxed" to h2_make_htx_request() so that
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we can control its level of acceptance of certain invalid requests at
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the proxy level with "option accept-invalid-http-request". The goal
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will be to add deactivable checks that are still desirable to have by
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default. For now no test is subject to it.
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(cherry picked from commit d93a00861d714313faa0395ff9e2acb14b0a2fca)
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[ad: backported for following fix : BUG/MINOR: h2: reject more chars
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from the :path pseudo header]
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Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
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(cherry picked from commit b6be1a4f858eb6602490c192235114c1a163fef9)
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Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
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(cherry picked from commit 26fa3a285df0748fc79e73e552161268b66fb527)
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Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
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(cherry picked from commit 014945a1508f43e88ac4e89950fa9037e4fb0679)
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Signed-off-by: Willy Tarreau <w@1wt.eu>
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---
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include/haproxy/h2.h | 2 +-
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src/h2.c | 6 +++++-
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src/mux_h2.c | 3 ++-
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3 files changed, 8 insertions(+), 3 deletions(-)
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diff --git a/include/haproxy/h2.h b/include/haproxy/h2.h
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index 8d2aa9511..4f872b99d 100644
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--- a/include/haproxy/h2.h
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+++ b/include/haproxy/h2.h
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@@ -207,7 +207,7 @@ extern struct h2_frame_definition h2_frame_definition[H2_FT_ENTRIES];
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/* various protocol processing functions */
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int h2_parse_cont_len_header(unsigned int *msgf, struct ist *value, unsigned long long *body_len);
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-int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *msgf, unsigned long long *body_len);
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+int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *msgf, unsigned long long *body_len, int relaxed);
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int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *msgf, unsigned long long *body_len, char *upgrade_protocol);
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int h2_make_htx_trailers(struct http_hdr *list, struct htx *htx);
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diff --git a/src/h2.c b/src/h2.c
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index e1554642e..94c384111 100644
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--- a/src/h2.c
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+++ b/src/h2.c
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@@ -399,8 +399,12 @@ static struct htx_sl *h2_prepare_htx_reqline(uint32_t fields, struct ist *phdr,
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*
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* The Cookie header will be reassembled at the end, and for this, the <list>
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* will be used to create a linked list, so its contents may be destroyed.
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+ *
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+ * When <relaxed> is non-nul, some non-dangerous checks will be ignored. This
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+ * is in order to satisfy "option accept-invalid-http-request" for
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+ * interoperability purposes.
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*/
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-int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *msgf, unsigned long long *body_len)
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+int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *msgf, unsigned long long *body_len, int relaxed)
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{
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struct ist phdr_val[H2_PHDR_NUM_ENTRIES];
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uint32_t fields; /* bit mask of H2_PHDR_FND_* */
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diff --git a/src/mux_h2.c b/src/mux_h2.c
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index 0ab86534c..61fd1a4d2 100644
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--- a/src/mux_h2.c
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+++ b/src/mux_h2.c
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@@ -4917,7 +4917,8 @@ static int h2c_decode_headers(struct h2c *h2c, struct buffer *rxbuf, uint32_t *f
|
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if (h2c->flags & H2_CF_IS_BACK)
|
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outlen = h2_make_htx_response(list, htx, &msgf, body_len, upgrade_protocol);
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else
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- outlen = h2_make_htx_request(list, htx, &msgf, body_len);
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+ outlen = h2_make_htx_request(list, htx, &msgf, body_len,
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+ !!(((const struct session *)h2c->conn->owner)->fe->options2 & PR_O2_REQBUG_OK));
|
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|
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if (outlen < 0 || htx_free_space(htx) < global.tune.maxrewrite) {
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/* too large headers? this is a stream error only */
|
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--
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2.43.0
|
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|
@ -0,0 +1,71 @@
|
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From af232e47e6264122bed3681210b054ff38ec8de8 Mon Sep 17 00:00:00 2001
|
||||
From: Willy Tarreau <w@1wt.eu>
|
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Date: Tue, 8 Aug 2023 15:40:49 +0200
|
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Subject: [PATCH] BUG/MINOR: h2: reject more chars from the :path pseudo header
|
||||
|
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This is the h2 version of this previous fix:
|
||||
|
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BUG/MINOR: h1: do not accept '#' as part of the URI component
|
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|
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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
|
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taking the '#' for a part of the path. It's still possible to fall back
|
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to the previous behavior using "option accept-invalid-http-request".
|
||||
|
||||
This patch modifies the request parser to change the ":path" pseudo header
|
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validation function with a new one that rejects 0x00-0x1F (control chars),
|
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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 <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 462a8600ce9e478573a957e046b446a7dcffd286)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 648e59e30723b8fd4e71aab02cb679f6ea7446e7)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit c8e07f2fd8b5462527f102f7145d6027c0d041da)
|
||||
[wt: minor ctx adjustments]
|
||||
Signed-off-by: Willy Tarreau <w@1wt.eu>
|
||||
---
|
||||
src/h2.c | 15 +++++++++++----
|
||||
1 file changed, 11 insertions(+), 4 deletions(-)
|
||||
|
||||
diff --git a/src/h2.c b/src/h2.c
|
||||
index 94c384111..e190c52b5 100644
|
||||
--- a/src/h2.c
|
||||
+++ b/src/h2.c
|
||||
@@ -440,11 +440,18 @@ 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) && 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) && 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
|
||||
|
@ -0,0 +1,59 @@
|
||||
From 0f57ac20b046b70275192651d7b6c978032e6a36 Mon Sep 17 00:00:00 2001
|
||||
From: Willy Tarreau <w@1wt.eu>
|
||||
Date: Tue, 8 Aug 2023 15:24:54 +0200
|
||||
Subject: [PATCH] MINOR: http: add new function http_path_has_forbidden_char()
|
||||
|
||||
As its name implies, this function checks if a path component has any
|
||||
forbidden headers starting at the designated location. The goal is to
|
||||
seek from the result of a successful ist_find_range() for more precise
|
||||
chars. Here we're focusing on 0x00-0x1F, 0x20 and 0x23 to make sure
|
||||
we're not too strict at this point.
|
||||
|
||||
(cherry picked from commit 30f58f4217d585efeac3d85cb1b695ba53b7760b)
|
||||
[ad: backported for following fix : BUG/MINOR: h2: reject more chars
|
||||
from the :path pseudo header]
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit b491940181a88bb6c69ab2afc24b93a50adfa67c)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit f7666e5e43ce63e804ebffdf224d92cfd3367282)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit c699bb17b7e334c9d56e829422e29e5a204615ec)
|
||||
[wt: adj minor ctx in http.h]
|
||||
Signed-off-by: Willy Tarreau <w@1wt.eu>
|
||||
---
|
||||
include/haproxy/http.h | 19 +++++++++++++++++++
|
||||
1 file changed, 19 insertions(+)
|
||||
|
||||
diff --git a/include/haproxy/http.h b/include/haproxy/http.h
|
||||
index 8a86cb6e9..e8c5b850f 100644
|
||||
--- a/include/haproxy/http.h
|
||||
+++ b/include/haproxy/http.h
|
||||
@@ -134,6 +134,25 @@ static inline enum http_etag_type http_get_etag_type(const struct ist etag)
|
||||
return ETAG_INVALID;
|
||||
}
|
||||
|
||||
+/* Looks into <ist> for forbidden characters for :path values (0x00..0x1F,
|
||||
+ * 0x20, 0x23), starting at pointer <start> which must be within <ist>.
|
||||
+ * Returns non-zero if such a character is found, 0 otherwise. When run on
|
||||
+ * unlikely header match, it's recommended to first check for the presence
|
||||
+ * of control chars using ist_find_ctl().
|
||||
+ */
|
||||
+static inline int http_path_has_forbidden_char(const struct ist ist, const char *start)
|
||||
+{
|
||||
+ do {
|
||||
+ if ((uint8_t)*start <= 0x23) {
|
||||
+ if ((uint8_t)*start < 0x20)
|
||||
+ return 1;
|
||||
+ if ((1U << ((uint8_t)*start & 0x1F)) & ((1<<3) | (1<<0)))
|
||||
+ return 1;
|
||||
+ }
|
||||
+ start++;
|
||||
+ } while (start < istend(ist));
|
||||
+ return 0;
|
||||
+}
|
||||
|
||||
#endif /* _HAPROXY_HTTP_H */
|
||||
|
||||
--
|
||||
2.43.0
|
||||
|
@ -0,0 +1,86 @@
|
||||
From edcff741698c9519dc44f3aa13de421baad7ff43 Mon Sep 17 00:00:00 2001
|
||||
From: Willy Tarreau <w@1wt.eu>
|
||||
Date: Tue, 8 Aug 2023 15:23:19 +0200
|
||||
Subject: [PATCH] MINOR: ist: add new function ist_find_range() to find a
|
||||
character range
|
||||
|
||||
This looks up the character range <min>..<max> in the input string and
|
||||
returns a pointer to the first one found. It's essentially the equivalent
|
||||
of ist_find_ctl() in that it searches by 32 or 64 bits at once, but deals
|
||||
with a range.
|
||||
|
||||
(cherry picked from commit 197668de975e495f0c0f0e4ff51b96203fa9842d)
|
||||
[ad: backported for following fix : BUG/MINOR: h2: reject more chars
|
||||
from the :path pseudo header]
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 451ac6628acc4b9eed3260501a49c60d4e4d4e55)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 3468f7f8e04c9c5ca5c985c7511e05e78fe1eded)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit b375df60341c7f7a4904c2d8041a09c66115c754)
|
||||
Signed-off-by: Willy Tarreau <w@1wt.eu>
|
||||
---
|
||||
include/import/ist.h | 47 ++++++++++++++++++++++++++++++++++++++++++++
|
||||
1 file changed, 47 insertions(+)
|
||||
|
||||
diff --git a/include/import/ist.h b/include/import/ist.h
|
||||
index 539a27d26..31566b105 100644
|
||||
--- a/include/import/ist.h
|
||||
+++ b/include/import/ist.h
|
||||
@@ -746,6 +746,53 @@ static inline const char *ist_find_ctl(const struct ist ist)
|
||||
return NULL;
|
||||
}
|
||||
|
||||
+/* Returns a pointer to the first character found <ist> that belongs to the
|
||||
+ * range [min:max] inclusive, or NULL if none is present. The function is
|
||||
+ * optimized for strings having no such chars by processing up to sizeof(long)
|
||||
+ * bytes at once on architectures supporting efficient unaligned accesses.
|
||||
+ * Despite this it is not very fast (~0.43 byte/cycle) and should mostly be
|
||||
+ * used on low match probability when it can save a call to a much slower
|
||||
+ * function. Will not work for characters 0x80 and above. It's optimized for
|
||||
+ * min and max to be known at build time.
|
||||
+ */
|
||||
+static inline const char *ist_find_range(const struct ist ist, unsigned char min, unsigned char max)
|
||||
+{
|
||||
+ const union { unsigned long v; } __attribute__((packed)) *u;
|
||||
+ const char *curr = (void *)ist.ptr - sizeof(long);
|
||||
+ const char *last = curr + ist.len;
|
||||
+ unsigned long l1, l2;
|
||||
+
|
||||
+ /* easier with an exclusive boundary */
|
||||
+ max++;
|
||||
+
|
||||
+ do {
|
||||
+ curr += sizeof(long);
|
||||
+ if (curr > last)
|
||||
+ break;
|
||||
+ u = (void *)curr;
|
||||
+ /* add 0x<min><min><min><min>..<min> then subtract
|
||||
+ * 0x<max><max><max><max>..<max> to the value to generate a
|
||||
+ * carry in the lower byte if the byte contains a lower value.
|
||||
+ * If we generate a bit 7 that was not there, it means the byte
|
||||
+ * was min..max.
|
||||
+ */
|
||||
+ l2 = u->v;
|
||||
+ l1 = ~l2 & ((~0UL / 255) * 0x80); /* 0x808080...80 */
|
||||
+ l2 += (~0UL / 255) * min; /* 0x<min><min>..<min> */
|
||||
+ l2 -= (~0UL / 255) * max; /* 0x<max><max>..<max> */
|
||||
+ } while ((l1 & l2) == 0);
|
||||
+
|
||||
+ last += sizeof(long);
|
||||
+ if (__builtin_expect(curr < last, 0)) {
|
||||
+ do {
|
||||
+ if ((unsigned char)(*curr - min) < (unsigned char)(max - min))
|
||||
+ return curr;
|
||||
+ curr++;
|
||||
+ } while (curr < last);
|
||||
+ }
|
||||
+ return NULL;
|
||||
+}
|
||||
+
|
||||
/* looks for first occurrence of character <chr> in string <ist> and returns
|
||||
* the tail of the string starting with this character, or (ist.end,0) if not
|
||||
* found.
|
||||
--
|
||||
2.43.0
|
||||
|
@ -0,0 +1,46 @@
|
||||
From c7492154ef07d6c08aa1eb52502697bbc3f42a69 Mon Sep 17 00:00:00 2001
|
||||
From: Willy Tarreau <w@1wt.eu>
|
||||
Date: Tue, 8 Aug 2023 19:52:45 +0200
|
||||
Subject: [PATCH] REGTESTS: http-rules: add accept-invalid-http-request for
|
||||
normalize-uri tests
|
||||
|
||||
We'll soon block the '#' by default so let's prepare the test to continue
|
||||
to work.
|
||||
|
||||
(cherry picked from commit 069d0e221e58a46119d7c049bb07fa4bcb8d0075)
|
||||
[ad: backported for following fix : BUG/MINOR: h2: reject more chars
|
||||
from the :path pseudo header]
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 1660481fab69856a39ac44cf88b76cdbcc0ea954)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 90d0300cea6cda18a4e20369f4dc0b4c4783d6c9)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 65849396fd6f192d9f14e81702c6c3851e580345)
|
||||
Signed-off-by: Willy Tarreau <w@1wt.eu>
|
||||
---
|
||||
reg-tests/http-rules/normalize_uri.vtc | 2 ++
|
||||
1 file changed, 2 insertions(+)
|
||||
|
||||
diff --git a/reg-tests/http-rules/normalize_uri.vtc b/reg-tests/http-rules/normalize_uri.vtc
|
||||
index 6a1dc31dc..56acf2cef 100644
|
||||
--- a/reg-tests/http-rules/normalize_uri.vtc
|
||||
+++ b/reg-tests/http-rules/normalize_uri.vtc
|
||||
@@ -127,6 +127,7 @@ haproxy h1 -conf {
|
||||
|
||||
frontend fe_fragment_strip
|
||||
bind "fd@${fe_fragment_strip}"
|
||||
+ option accept-invalid-http-request
|
||||
|
||||
http-request set-var(txn.before) url
|
||||
http-request normalize-uri fragment-strip
|
||||
@@ -139,6 +140,7 @@ haproxy h1 -conf {
|
||||
|
||||
frontend fe_fragment_encode
|
||||
bind "fd@${fe_fragment_encode}"
|
||||
+ option accept-invalid-http-request
|
||||
|
||||
http-request set-var(txn.before) url
|
||||
http-request normalize-uri fragment-encode
|
||||
--
|
||||
2.43.0
|
||||
|
@ -0,0 +1,275 @@
|
||||
From ba9afd2774c03e434165475b537d0462801f49bb Mon Sep 17 00:00:00 2001
|
||||
From: Willy Tarreau <w@1wt.eu>
|
||||
Date: Wed, 9 Aug 2023 08:32:48 +0200
|
||||
Subject: [PATCH] BUG/MAJOR: http: reject any empty content-length header value
|
||||
|
||||
The content-length header parser has its dedicated function, in order
|
||||
to take extreme care about invalid, unparsable, or conflicting values.
|
||||
But there's a corner case in it, by which it stops comparing values
|
||||
when reaching the end of the header. This has for a side effect that
|
||||
an empty value or a value that ends with a comma does not deserve
|
||||
further analysis, and it acts as if the header was absent.
|
||||
|
||||
While this is not necessarily a problem for the value ending with a
|
||||
comma as it will be cause a header folding and will disappear, it is a
|
||||
problem for the first isolated empty header because this one will not
|
||||
be recontructed when next ones are seen, and will be passed as-is to the
|
||||
backend server. A vulnerable HTTP/1 server hosted behind haproxy that
|
||||
would just use this first value as "0" and ignore the valid one would
|
||||
then not be protected by haproxy and could be attacked this way, taking
|
||||
the payload for an extra request.
|
||||
|
||||
In field the risk depends on the server. Most commonly used servers
|
||||
already have safe content-length parsers, but users relying on haproxy
|
||||
to protect a known-vulnerable server might be at risk (and the risk of
|
||||
a bug even in a reputable server should never be dismissed).
|
||||
|
||||
A configuration-based work-around consists in adding the following rule
|
||||
in the frontend, to explicitly reject requests featuring an empty
|
||||
content-length header that would have not be folded into an existing
|
||||
one:
|
||||
|
||||
http-request deny if { hdr_len(content-length) 0 }
|
||||
|
||||
The real fix consists in adjusting the parser so that it always expects a
|
||||
value at the beginning of the header or after a comma. It will now reject
|
||||
requests and responses having empty values anywhere in the C-L header.
|
||||
|
||||
This needs to be backported to all supported versions. Note that the
|
||||
modification was made to functions h1_parse_cont_len_header() and
|
||||
http_parse_cont_len_header(). Prior to 2.8 the latter was in
|
||||
h2_parse_cont_len_header(). One day the two should be refused but the
|
||||
former is also used by Lua.
|
||||
|
||||
The HTTP messaging reg-tests were completed to test these cases.
|
||||
|
||||
Thanks to Ben Kallus of Dartmouth College and Narf Industries for
|
||||
reporting this! (this is in GH #2237).
|
||||
|
||||
(cherry picked from commit 6492f1f29d738457ea9f382aca54537f35f9d856)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit a32f99f6f991d123ea3e307bf8aa63220836d365)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit 65921ee12d88e9fb1fa9f6cd8198fd64b3a3f37f)
|
||||
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
||||
(cherry picked from commit d17c50010d591d1c070e1cb0567a06032d8869e9)
|
||||
[wt: applied to h2_parse_cont_len_header() in src/h2.c instead]
|
||||
Signed-off-by: Willy Tarreau <w@1wt.eu>
|
||||
---
|
||||
reg-tests/http-messaging/h1_to_h1.vtc | 26 ++++++++++++
|
||||
reg-tests/http-messaging/h2_to_h1.vtc | 60 +++++++++++++++++++++++++++
|
||||
src/h1.c | 20 +++++++--
|
||||
src/h2.c | 20 +++++++--
|
||||
4 files changed, 120 insertions(+), 6 deletions(-)
|
||||
|
||||
diff --git a/reg-tests/http-messaging/h1_to_h1.vtc b/reg-tests/http-messaging/h1_to_h1.vtc
|
||||
index c7d00858e..603c03210 100644
|
||||
--- a/reg-tests/http-messaging/h1_to_h1.vtc
|
||||
+++ b/reg-tests/http-messaging/h1_to_h1.vtc
|
||||
@@ -275,3 +275,29 @@ client c3h1 -connect ${h1_feh1_sock} {
|
||||
# arrive here.
|
||||
expect_close
|
||||
} -run
|
||||
+
|
||||
+client c4h1 -connect ${h1_feh1_sock} {
|
||||
+ # this request is invalid and advertises an invalid C-L ending with an
|
||||
+ # empty value, which results in a stream error.
|
||||
+ txreq \
|
||||
+ -req "GET" \
|
||||
+ -url "/test31.html" \
|
||||
+ -hdr "content-length: 0," \
|
||||
+ -hdr "connection: close"
|
||||
+ rxresp
|
||||
+ expect resp.status == 400
|
||||
+ expect_close
|
||||
+} -run
|
||||
+
|
||||
+client c5h1 -connect ${h1_feh1_sock} {
|
||||
+ # this request is invalid and advertises an empty C-L, which results
|
||||
+ # in a stream error.
|
||||
+ txreq \
|
||||
+ -req "GET" \
|
||||
+ -url "/test41.html" \
|
||||
+ -hdr "content-length:" \
|
||||
+ -hdr "connection: close"
|
||||
+ rxresp
|
||||
+ expect resp.status == 400
|
||||
+ expect_close
|
||||
+} -run
|
||||
diff --git a/reg-tests/http-messaging/h2_to_h1.vtc b/reg-tests/http-messaging/h2_to_h1.vtc
|
||||
index 0d2b1e5f2..ec7a7c123 100644
|
||||
--- a/reg-tests/http-messaging/h2_to_h1.vtc
|
||||
+++ b/reg-tests/http-messaging/h2_to_h1.vtc
|
||||
@@ -10,6 +10,8 @@ barrier b1 cond 2 -cyclic
|
||||
barrier b2 cond 2 -cyclic
|
||||
barrier b3 cond 2 -cyclic
|
||||
barrier b4 cond 2 -cyclic
|
||||
+barrier b5 cond 2 -cyclic
|
||||
+barrier b6 cond 2 -cyclic
|
||||
|
||||
server s1 {
|
||||
rxreq
|
||||
@@ -31,6 +33,12 @@ server s1 {
|
||||
|
||||
barrier b4 sync
|
||||
# the next request is never received
|
||||
+
|
||||
+ barrier b5 sync
|
||||
+ # the next request is never received
|
||||
+
|
||||
+ barrier b6 sync
|
||||
+ # the next request is never received
|
||||
} -repeat 2 -start
|
||||
|
||||
haproxy h1 -conf {
|
||||
@@ -121,6 +129,32 @@ client c1h2 -connect ${h1_feh2_sock} {
|
||||
txdata -data "this is sent and ignored"
|
||||
rxrst
|
||||
} -run
|
||||
+
|
||||
+ # fifth request is invalid and advertises an invalid C-L ending with an
|
||||
+ # empty value, which results in a stream error.
|
||||
+ stream 9 {
|
||||
+ barrier b5 sync
|
||||
+ txreq \
|
||||
+ -req "GET" \
|
||||
+ -scheme "https" \
|
||||
+ -url "/test5.html" \
|
||||
+ -hdr "content-length" "0," \
|
||||
+ -nostrend
|
||||
+ rxrst
|
||||
+ } -run
|
||||
+
|
||||
+ # sixth request is invalid and advertises an empty C-L, which results
|
||||
+ # in a stream error.
|
||||
+ stream 11 {
|
||||
+ barrier b6 sync
|
||||
+ txreq \
|
||||
+ -req "GET" \
|
||||
+ -scheme "https" \
|
||||
+ -url "/test6.html" \
|
||||
+ -hdr "content-length" "" \
|
||||
+ -nostrend
|
||||
+ rxrst
|
||||
+ } -run
|
||||
} -run
|
||||
|
||||
# HEAD requests : don't work well yet
|
||||
@@ -263,4 +297,30 @@ client c3h2 -connect ${h1_feh2_sock} {
|
||||
txdata -data "this is sent and ignored"
|
||||
rxrst
|
||||
} -run
|
||||
+
|
||||
+ # fifth request is invalid and advertises invalid C-L ending with an
|
||||
+ # empty value, which results in a stream error.
|
||||
+ stream 9 {
|
||||
+ barrier b5 sync
|
||||
+ txreq \
|
||||
+ -req "POST" \
|
||||
+ -scheme "https" \
|
||||
+ -url "/test25.html" \
|
||||
+ -hdr "content-length" "0," \
|
||||
+ -nostrend
|
||||
+ rxrst
|
||||
+ } -run
|
||||
+
|
||||
+ # sixth request is invalid and advertises an empty C-L, which results
|
||||
+ # in a stream error.
|
||||
+ stream 11 {
|
||||
+ barrier b6 sync
|
||||
+ txreq \
|
||||
+ -req "POST" \
|
||||
+ -scheme "https" \
|
||||
+ -url "/test26.html" \
|
||||
+ -hdr "content-length" "" \
|
||||
+ -nostrend
|
||||
+ rxrst
|
||||
+ } -run
|
||||
} -run
|
||||
diff --git a/src/h1.c b/src/h1.c
|
||||
index 73de48be0..eeda311b7 100644
|
||||
--- a/src/h1.c
|
||||
+++ b/src/h1.c
|
||||
@@ -34,13 +34,20 @@ int h1_parse_cont_len_header(struct h1m *h1m, struct ist *value)
|
||||
int not_first = !!(h1m->flags & H1_MF_CLEN);
|
||||
struct ist word;
|
||||
|
||||
- word.ptr = value->ptr - 1; // -1 for next loop's pre-increment
|
||||
+ word.ptr = value->ptr;
|
||||
e = value->ptr + value->len;
|
||||
|
||||
- while (++word.ptr < e) {
|
||||
+ while (1) {
|
||||
+ if (word.ptr >= e) {
|
||||
+ /* empty header or empty value */
|
||||
+ goto fail;
|
||||
+ }
|
||||
+
|
||||
/* skip leading delimiter and blanks */
|
||||
- if (unlikely(HTTP_IS_LWS(*word.ptr)))
|
||||
+ if (unlikely(HTTP_IS_LWS(*word.ptr))) {
|
||||
+ word.ptr++;
|
||||
continue;
|
||||
+ }
|
||||
|
||||
/* digits only now */
|
||||
for (cl = 0, n = word.ptr; n < e; n++) {
|
||||
@@ -79,6 +86,13 @@ int h1_parse_cont_len_header(struct h1m *h1m, struct ist *value)
|
||||
h1m->flags |= H1_MF_CLEN;
|
||||
h1m->curr_len = h1m->body_len = cl;
|
||||
*value = word;
|
||||
+
|
||||
+ /* Now either n==e and we're done, or n points to the comma,
|
||||
+ * and we skip it and continue.
|
||||
+ */
|
||||
+ if (n++ == e)
|
||||
+ break;
|
||||
+
|
||||
word.ptr = n;
|
||||
}
|
||||
/* here we've reached the end with a single value or a series of
|
||||
diff --git a/src/h2.c b/src/h2.c
|
||||
index dd1f7d9b6..e1554642e 100644
|
||||
--- a/src/h2.c
|
||||
+++ b/src/h2.c
|
||||
@@ -80,13 +80,20 @@ int h2_parse_cont_len_header(unsigned int *msgf, struct ist *value, unsigned lon
|
||||
int not_first = !!(*msgf & H2_MSGF_BODY_CL);
|
||||
struct ist word;
|
||||
|
||||
- word.ptr = value->ptr - 1; // -1 for next loop's pre-increment
|
||||
+ word.ptr = value->ptr;
|
||||
e = value->ptr + value->len;
|
||||
|
||||
- while (++word.ptr < e) {
|
||||
+ while (1) {
|
||||
+ if (word.ptr >= e) {
|
||||
+ /* empty header or empty value */
|
||||
+ goto fail;
|
||||
+ }
|
||||
+
|
||||
/* skip leading delimiter and blanks */
|
||||
- if (unlikely(HTTP_IS_LWS(*word.ptr)))
|
||||
+ if (unlikely(HTTP_IS_LWS(*word.ptr))) {
|
||||
+ word.ptr++;
|
||||
continue;
|
||||
+ }
|
||||
|
||||
/* digits only now */
|
||||
for (cl = 0, n = word.ptr; n < e; n++) {
|
||||
@@ -125,6 +132,13 @@ int h2_parse_cont_len_header(unsigned int *msgf, struct ist *value, unsigned lon
|
||||
*msgf |= H2_MSGF_BODY_CL;
|
||||
*body_len = cl;
|
||||
*value = word;
|
||||
+
|
||||
+ /* Now either n==e and we're done, or n points to the comma,
|
||||
+ * and we skip it and continue.
|
||||
+ */
|
||||
+ if (n++ == e)
|
||||
+ break;
|
||||
+
|
||||
word.ptr = n;
|
||||
}
|
||||
/* here we've reached the end with a single value or a series of
|
||||
--
|
||||
2.43.0
|
||||
|
Loading…
Reference in new issue