commit bb3f607590a102321a15a8a17474d87da8bec32c Author: Tomas Korbar Date: Tue Oct 17 16:52:32 2023 +0200 Upstream #3997 PR Fix CVE-2023-44487 diff --git a/bin/varnishd/VSC_main.vsc b/bin/varnishd/VSC_main.vsc index 7b32584..d55b9df 100644 --- a/bin/varnishd/VSC_main.vsc +++ b/bin/varnishd/VSC_main.vsc @@ -631,6 +631,14 @@ Number of session closes with Error VCL_FAILURE (VCL failure) +.. varnish_vsc:: sc_rapid_reset + :level: diag + :oneliner: Session Err RAPID_RESET + + Number of times we failed an http/2 session because it hit its + configured limits for the number of permitted rapid stream + resets. + .. varnish_vsc:: client_resp_500 :level: diag :group: wrk diff --git a/bin/varnishd/http2/cache_http2.h b/bin/varnishd/http2/cache_http2.h index ea5eb52..9088e21 100644 --- a/bin/varnishd/http2/cache_http2.h +++ b/bin/varnishd/http2/cache_http2.h @@ -184,6 +184,8 @@ struct h2_sess { VTAILQ_HEAD(,h2_req) txqueue; h2_error error; + double rst_budget; + vtim_real last_rst; }; #define ASSERT_RXTHR(h2) do {assert(h2->rxthr == pthread_self());} while(0) diff --git a/bin/varnishd/http2/cache_http2_proto.c b/bin/varnishd/http2/cache_http2_proto.c index 3597ec1..408acad 100644 --- a/bin/varnishd/http2/cache_http2_proto.c +++ b/bin/varnishd/http2/cache_http2_proto.c @@ -45,6 +45,7 @@ #include "vtcp.h" #include "vtim.h" +#define H2_CUSTOM_ERRORS #define H2EC1(U,v,r,d) const struct h2_error_s H2CE_##U[1] = {{#U,d,v,0,1,r}}; #define H2EC2(U,v,r,d) const struct h2_error_s H2SE_##U[1] = {{#U,d,v,1,0,r}}; #define H2EC3(U,v,r,d) H2EC1(U,v,r,d) H2EC2(U,v,r,d) @@ -304,9 +305,46 @@ h2_rx_push_promise(struct worker *wrk, struct h2_sess *h2, struct h2_req *r2) /********************************************************************** */ +static h2_error +h2_rapid_reset(struct worker *wrk, struct h2_sess *h2, struct h2_req *r2) +{ + vtim_real now; + vtim_dur d; + + CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC); + ASSERT_RXTHR(h2); + CHECK_OBJ_NOTNULL(r2, H2_REQ_MAGIC); + + if (cache_param->h2_rapid_reset_limit == 0) + return (0); + + now = VTIM_real(); + CHECK_OBJ_NOTNULL(r2->req, REQ_MAGIC); + AN(r2->req->t_first); + if (now - r2->req->t_first > cache_param->h2_rapid_reset) + return (0); + + d = now - h2->last_rst; + h2->rst_budget += cache_param->h2_rapid_reset_limit * d / + cache_param->h2_rapid_reset_period; + h2->rst_budget = vmin_t(double, h2->rst_budget, + cache_param->h2_rapid_reset_limit); + h2->last_rst = now; + + if (h2->rst_budget < 1.0) { + Lck_Lock(&h2->sess->mtx); + VSLb(h2->vsl, SLT_Error, "H2: Hit RST limit. Closing session."); + Lck_Unlock(&h2->sess->mtx); + return (H2CE_RAPID_RESET); + } + h2->rst_budget -= 1.0; + return (0); +} + static h2_error v_matchproto_(h2_rxframe_f) h2_rx_rst_stream(struct worker *wrk, struct h2_sess *h2, struct h2_req *r2) { + h2_error h2e; CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC); ASSERT_RXTHR(h2); @@ -316,8 +354,9 @@ h2_rx_rst_stream(struct worker *wrk, struct h2_sess *h2, struct h2_req *r2) return (H2CE_FRAME_SIZE_ERROR); if (r2 == NULL) return (0); + h2e = h2_rapid_reset(wrk, h2, r2); h2_kill_req(wrk, h2, r2, h2_streamerror(vbe32dec(h2->rxf_data))); - return (0); + return (h2e); } /********************************************************************** diff --git a/bin/varnishd/http2/cache_http2_session.c b/bin/varnishd/http2/cache_http2_session.c index 36d4a1c..f81c94a 100644 --- a/bin/varnishd/http2/cache_http2_session.c +++ b/bin/varnishd/http2/cache_http2_session.c @@ -128,6 +128,9 @@ h2_init_sess(const struct worker *wrk, struct sess *sp, h2_local_settings(&h2->local_settings); h2->remote_settings = H2_proto_settings; h2->decode = decode; + h2->rst_budget = cache_param->h2_rapid_reset_limit; + h2->last_rst = sp->t_open; + AZ(isnan(h2->last_rst)); AZ(VHT_Init(h2->dectbl, h2->local_settings.header_table_size)); diff --git a/bin/varnishtest/tests/r03996.vtc b/bin/varnishtest/tests/r03996.vtc new file mode 100644 index 0000000..3fee370 --- /dev/null +++ b/bin/varnishtest/tests/r03996.vtc @@ -0,0 +1,51 @@ +varnishtest "h2 rapid reset" + +barrier b1 sock 5 + +server s1 { + rxreq + txresp +} -start + +varnish v1 -cliok "param.set feature +http2" +varnish v1 -cliok "param.set debug +syncvsl" +varnish v1 -cliok "param.set h2_rapid_reset_limit 3" +varnish v1 -cliok "param.set h2_rapid_reset 5" + +varnish v1 -vcl+backend { + import vtc; + + sub vcl_recv { + vtc.barrier_sync("${b1_sock}"); + } + +} -start + +client c1 { + stream 0 { + rxgoaway + expect goaway.err == ENHANCE_YOUR_CALM + } -start + + stream 1 { + txreq + txrst + } -run + stream 3 { + txreq + txrst + } -run + stream 5 { + txreq + txrst + } -run + stream 7 { + txreq + txrst + } -run + + barrier b1 sync + stream 0 -wait +} -run + +varnish v1 -expect sc_rapid_reset == 1 diff --git a/include/tbl/h2_error.h b/include/tbl/h2_error.h index e8104f8..11051de 100644 --- a/include/tbl/h2_error.h +++ b/include/tbl/h2_error.h @@ -147,5 +147,17 @@ H2_ERROR( /* descr */ "Use HTTP/1.1 for the request" ) +#ifdef H2_CUSTOM_ERRORS +H2_ERROR( + /* name */ RAPID_RESET, + /* val */ 11, /* ENHANCE_YOUR_CALM */ + /* types */ 1, + /* reason */ SC_RAPID_RESET, + /* descr */ "http/2 rapid reset detected" +) + +# undef H2_CUSTOM_ERRORS +#endif + #undef H2_ERROR /*lint -restore */ diff --git a/include/tbl/params.h b/include/tbl/params.h index cca420c..4014dd6 100644 --- a/include/tbl/params.h +++ b/include/tbl/params.h @@ -1217,6 +1217,47 @@ PARAM_SIMPLE( "HTTP2 maximum size of an uncompressed header list." ) +PARAM_SIMPLE( + /* name */ h2_rapid_reset, + /* typ */ timeout, + /* min */ "0.000", + /* max */ NULL, + /* def */ "1.000", + /* units */ "seconds", + /* descr */ + "The upper threshold for how rapid an http/2 RST has to come for " + "it to be treated as suspect and subjected to the rate limits " + "specified by h2_rapid_reset_limit and h2_rapid_reset_period.", + /* flags */ EXPERIMENTAL, +) + +PARAM_SIMPLE( + /* name */ h2_rapid_reset_limit, + /* typ */ uint, + /* min */ "0", + /* max */ NULL, + /* def */ "3600", + /* units */ NULL, + /* descr */ + "HTTP2 RST Allowance.\n" + "Specifies the maximum number of allowed stream resets issued by\n" + "a client over a time period before the connection is closed.\n" + "Setting this parameter to 0 disables the limit.", + /* flags */ EXPERIMENTAL, +) + +PARAM_SIMPLE( + /* name */ h2_rapid_reset_period, + /* typ */ timeout, + /* min */ "1.000", + /* max */ NULL, + /* def */ "60.000", + /* units */ "seconds", + /* descr */ + "HTTP2 sliding window duration for h2_rapid_reset_limit.", + /* flags */ EXPERIMENTAL|WIZARD, +) + /*-------------------------------------------------------------------- * Memory pool parameters */ diff --git a/include/tbl/sess_close.h b/include/tbl/sess_close.h index 9748314..6d2f635 100644 --- a/include/tbl/sess_close.h +++ b/include/tbl/sess_close.h @@ -50,6 +50,7 @@ SESS_CLOSE(PIPE_OVERFLOW, pipe_overflow,1, "Session pipe overflow") SESS_CLOSE(RANGE_SHORT, range_short, 1, "Insufficient data for range") SESS_CLOSE(REQ_HTTP20, req_http20, 1, "HTTP2 not accepted") SESS_CLOSE(VCL_FAILURE, vcl_failure, 1, "VCL failure") +SESS_CLOSE(RAPID_RESET, rapid_reset, 1, "HTTP2 rapid reset") #undef SESS_CLOSE /*lint -restore */ diff --git a/include/vdef.h b/include/vdef.h index a9111fe..c85bea8 100644 --- a/include/vdef.h +++ b/include/vdef.h @@ -106,6 +106,47 @@ # define v_dont_optimize #endif +/********************************************************************** + * Find the minimum or maximum values. + * Only evaluate the expression once and perform type checking. + */ + +/* ref: https://stackoverflow.com/a/17624752 */ + +#define VINDIRECT(a, b, c) a ## b ## c +#define VCOMBINE(a, b, c) VINDIRECT(a, b, c) + +#if defined(__COUNTER__) +# define VUNIQ_NAME(base) VCOMBINE(base, __LINE__, __COUNTER__) +#else +# define VUNIQ_NAME(base) VCOMBINE(base, __LINE__, 0) +#endif + +#ifdef _lint +#define typeof(x) __typeof__(x) +#endif + +/* ref: https://gcc.gnu.org/onlinedocs/gcc/Typeof.html */ + +#define _vtake(op, ta, tb, a, b, _va, _vb) \ + ({ \ + ta _va = (a); \ + tb _vb = (b); \ + (void)(&_va == &_vb); \ + _va op _vb ? _va : _vb; \ +}) + +#define opmin < +#define opmax > +#define vtake(n, ta, tb, a, b) _vtake(op ## n, ta, tb, a, b, \ + VUNIQ_NAME(_v ## n ## A), VUNIQ_NAME(_v ## n ## B)) + +#define vmin(a, b) vtake(min, typeof(a), typeof(b), a, b) +#define vmax(a, b) vtake(max, typeof(a), typeof(b), a, b) + +#define vmin_t(type, a, b) vtake(min, type, type, a, b) +#define vmax_t(type, a, b) vtake(max, type, type, a, b) + /********************************************************************* * Pointer alignment magic */