From c37a465897c3bf6663140858ca82e9dd04f9c036 Mon Sep 17 00:00:00 2001
From: Xavier Leroy <xavier.leroy@college-de-france.fr>
Date: Sun, 10 Dec 2023 19:24:38 +0100
Subject: [PATCH] Fail when unmarshaling would produce non-canonical big
 integers

Fixes: #148
---
 caml_z.c                |  12 ++++
 tests/Makefile          |   8 +++
 tests/extern.data32     | Bin 0 -> 23522 bytes
 tests/extern.data64     | Bin 0 -> 21510 bytes
 tests/extern.ml         |  14 +++++
 tests/intern.ml         |  24 ++++++++
 tests/intern.output3232 | 127 ++++++++++++++++++++++++++++++++++++++++
 tests/intern.output3264 | 127 ++++++++++++++++++++++++++++++++++++++++
 tests/intern.output6432 | 127 ++++++++++++++++++++++++++++++++++++++++
 tests/intern.output6464 | 127 ++++++++++++++++++++++++++++++++++++++++
 10 files changed, 566 insertions(+)
 create mode 100644 tests/extern.data32
 create mode 100644 tests/extern.data64
 create mode 100644 tests/extern.ml
 create mode 100644 tests/intern.ml
 create mode 100644 tests/intern.output3232
 create mode 100644 tests/intern.output3264
 create mode 100644 tests/intern.output6432
 create mode 100644 tests/intern.output6464

diff --git a/caml_z.c b/caml_z.c
index 02e758d..c0b11c4 100644
--- a/caml_z.c
+++ b/caml_z.c
@@ -3398,6 +3398,10 @@ static void ml_z_custom_serialize(value v,
 /* XXX: serializing a large (i.e., > 2^31) int on a 64-bit machine and
    deserializing on a 32-bit machine will fail (instead of returning a
    block).
+   YYY: serializing a large (i.e., > 2^31 and < 2^62) int on a
+   32-bit machine and deserializing on a 64-bit machine must fail
+   (instead of returning a block containing a non-normalized big integer)
+   (issue #148).
  */
 static uintnat ml_z_custom_deserialize(void * dst)
 {
@@ -3444,6 +3448,14 @@ static uintnat ml_z_custom_deserialize(void * dst)
 #if Z_PERFORM_CHECK
   d[szw] = 0xDEADBEEF ^ szw;
   szw++;
+#endif
+#if Z_USE_NATINT
+  if (i == 0 ||
+      (i == 1 && (d[0] <= Z_MAX_INT || (d[0] == -Z_MIN_INT && sign)))) {
+    /* Issue #148: this is not a canonical representation,
+       so we raise a Failure */
+    caml_deserialize_error("Z.t value produced on a 32-bit platform cannot be read on a 64-bit platform");
+  }
 #endif
   return (szw+1) * sizeof(mp_limb_t);
 }
diff --git a/tests/Makefile b/tests/Makefile
index 760294b..80762cc 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -50,6 +50,14 @@ test:: tst_extract.exe
 	@echo "Testing extract..."
 	@if ./tst_extract.exe; then echo "tst_extract: passed"; else echo "tst_extract: FAILED"; exit 2; fi
 
+test:: intern.exe
+	@echo "Testing unmarshaling..."
+	@if ./intern.exe extern.data32 | cmp -s intern.output32$(WORDSIZE) -; then echo "intern 32: passed"; else echo "intern 32: failed"; exit 2; fi
+	@if ./intern.exe extern.data64 | cmp -s intern.output64$(WORDSIZE) -; then echo "intern 64: passed"; else echo "intern 64: failed"; exit 2; fi
+
+extern.data$(WORDSIZE): extern.exe
+	./extern.exe extern.data$(WORDSIZE)
+
 tofloat.exe: tofloat.ml setround.o ../zarith.cmxa
 	ocamlopt -I .. -ccopt "-L.." zarith.cmxa -o tofloat.exe \
            setround.o tofloat.ml
diff --git a/tests/extern.data32 b/tests/extern.data32
new file mode 100644
index 0000000000000000000000000000000000000000..60d155d7ed0ac761c3dec73daeceb444125bc32b
GIT binary patch
literal 23522
zcmbW8L2e{96oxC4KxToIS+IZw>Y4=$PSGua1Ut9^oP$jl(p-Tna10b~5^fN7K?+m6
z=d|r-``P)bN=i?t_V4d~?RHhuPx<isAAe5MbR|FO`0j&q^4rVFH))vu^6Z}d&zs-}
z@8tJx{>eT2uQ$O@-pL=`{G)sJA8&$Rypun>`3Lvx-|pFyH|^OSdhee7>vHzmF2dEc
zxP$$P{jtBf6JJg4>1lOOum0%u${qd2AARM|{m~!&(VzRqAARl5{p^o^_UC@<kG}Qi
ze)2~@`E$SXN8kB#Kl-B|{kdm<^ueF|!5{tL&wcVoAN{%S{n7Vv?oaHSTP`<?KmP2`
z-Wk1gW|s@!<?UHx*EoOq#JYA8@<fLr4nE_m$N1PutRH)fn@(c7?lGP_iS@b1c-u)#
zw>`#FC$T>D81FiX>8{6k>?GF59%Jq#rbCbM&`GQhJ;te%n2tTheJ8Qr_ZUkjF`avi
zUSeH34E<c-zjxOjqnD6<<L?jsMBy@Id-!`$wuhgPCwzu%4?iK>!)M6$@DuWc&yelm
zCuDp04A~xjLZ0v$vOWBSY!9Cy+rv-D6Fy_^B@R8tLoXpuM8=mgM&C`k5;tG`{Hy#k
z=_{s(T7@T0?)%`_<K9cmO~@0QxXWdh*Nc==&SY>@MKg!NX6CQNOV8<@C%#sn$?tlE
z*DAblI)ap<sT-L+zCVVu>!h1zkF}%OwUjWs+4IA4LO^Rbvco{CpAte~3n4j}Ys#>s
z<e;D0FAFvdBnL`J4wR4_bTLRt$>A0Tk^?0q2TDi|x+69@+`&L{poHW=3CUrGC53>#
zTMsah94H|<P(mn4A5QYKX&sI*kQ^u>IZ%QW@^W2T<d;njXBbEhl#m=KK?=FtP$jy_
zVcqJWHzz_!4wR4`<nm1jA)xy~ZxAF9O48H>3E2S>LP>!jmv2&12m}YYe3L+SfQ0M-
z3E4p|-=w7MAeV0v$PSQ@9Uvh)$mN@qlpW;qO#;~g60!p%WQUoRlpPK%kR2c)J3vBq
zII)tl!;uBD10-YzNXQNgD=9miSs*(=LUw?J>>!tK^7hUS>sALy$PSQT9Mbp4!;jL&
zfl23ekQ)Sfm5c);7>D#dHFdb=B`HS#r+T9UBk0un!9M&$2w`Nn$E~-#qyP{QA((Yw
zgqPw2B7N^p*Wr$r^y0t>#(@!x!;DG_ftPhSpn%yAj9?rX!8n{yNyg!b0>*(6i~}PW
zhXs{n9L^|U92mhkFoJPNU!KwZux@o=1mnO6*5M7gYM6CMeafM<S%(P`tV8@xa!9Za
zH(MR9Nx(WFf^|Ry>+qJ8WY^)A1grxhSO-L~4(~`w*5Qr>tOFug2Sl(AGbzbB97w=A
zAcA#31nY1jC0U0f30Mb2unve|9TrlObvToNbwC8`5DD)EtLHzJpHD758vX85k1zBg
zHX*_&QkI6^zI@(D{f8k%@tY|c+C<T^62){1hNXp2bW!Bx1sH~O+-6b;Z6$^B^g$2P
zIT)6wV?T=|(>)l53MWb`oG2-jrw@9VPQtJ}9h;m?H(?kmoG7VqqNGrsKImaO3&Zks
zY;rQ)g<+_0qNKu!l0td<pvNpfWNYZy<aB_c!fD<TitlntlDYHFJwZ|kMbZ(53MWb`
z)`^lrdHSHoB0rng=?p`K6D1W+lq3b^b<!KtW~X(J6D1W+lvFz9PQ`n9LMQCspyPYb
z^h1WBP@dw#0ZAdWm85`lC)69%_I1kLiw#bYR60RY>6AMe!}3BXy?VKuF${(BG#L&^
zDxDxn0ePKrXJc4i2qmZ7-57>SCrB!tAgOek_q_KGEL1u{Qt1RqrPGO(7eZ;Bjx1C<
zK~m`iNu|@m$}64DEL1u{Qt1RqrITE~w_o?xJx-8RIzdw9lsYBv<q4e-+@ItIMP7(d
zp5k5(Myi|`Ndft~mpdn0oKp8>7^<97kLLAI+PNzuRZgjsG9-miCZ%r5FjP4)QV4A&
zRZgk1GAyrhO5K%VsB&VY%88LGrx|UH%ISbYl@lXXPK;DJoltp|(-DO#Cq}BA7^!kv
zP<fTp8HFk*Myi|`sd7r4nfLO9PDrlh>mDaYs+<_9c8Z;vO-`{}GYp0D6n8lgsdhpn
z1(^HO6gxM=@<J$IVb|Eb8HQ>nM5>(-sdkE;oMCyjQ|#spL$wnk)lP_1JH^h<u)NwS
zc6WxM+6j?rCq$~9X7bUkb~=zy?Sx3R6C%}4CsJPRbR?nL36W|iM5>(@QeN$JCZXC1
zk!q(%`dUiR=kzP|*mwF|%aSAXo%GA=bm&M@q6X6U%X$sGgoZSod>5^DLo_Y1pqXCO
zu*?uN*LC~%F~eZvM~NZ0huAopj?u8x#?f?*hQY>>5*tTKY#dDoX;^CGXu3$lVB<)M
zjUy#Cj{3$WTdHw1U8QY~l-M{@V&gdPbv(devyPP5I8ve%R$g;Xa$?sy9$~O?q{PON
z5~Z-xagh_d9M3S=I8tKcNQqKd>8Q8RU5@KsM@noQDY13T9jf7_BLwZ;%JjpA!Db!J
z-wC}Q+(T>~bH{2(Y#npgY8Y%CA+cRYNNgQ*2Wwbr>zKP(!(i(OiLE0fwvKYU+P5Eb
zS8JmqB({!_*gDR89S<znt|KJ2j*!?oo>-|NSX=>)EZ90iV(SQrt>eN<Z5_`n*g8UD
z>j;Uhquj3c?Z<VmBP6ztkmxw34%zV1(XM0e#|?w+I_AHVdOcX|4oGwyQ^#ybbR1LH
zY#4ML8PQosMsyrg2W?oY<Cyw&!=U5Hh>jy8I*zHMHZ0X~OkK5M&~ao$$B_{o$9eBH
z=YWEaBO^MFjOaL?P^r#39#PP7WJJf25go?`mFhU2QP6Q@M8}a49mmv>8*VGdaoy|4
zh>jy8dXBL}x7jgv>4rgP9n;^5y&f#@kLfSchC$CUcI;jcR>at~8wNc`MD*4X5k1G)
z!5fz9y;oxwZy59(5z%u*M9(pH^oFH+j<KsZ40?`;=s6;y=Q!{DOuimS&~rpY&k+$l
z#}g^lTgM{_dX9+bIU=IxxR6pk$1@3fj)>?vM&dV8jy|uwlTR;y?-u%v^53)kOtA^6
bzlTFdlX7+NyXxAyUV=la0(Mh1+))1q)^6Tx

literal 0
HcmV?d00001

diff --git a/tests/extern.data64 b/tests/extern.data64
new file mode 100644
index 0000000000000000000000000000000000000000..096750b0952b63b33181f8220c1803e4f13a813a
GIT binary patch
literal 21510
zcmbuHL2fKH5Qck_JQ5_NWWnMsK+_wRoMBo533hOU$2r(^BfTqd1&)D+n+!JyyC8*_
zs<OMMZU5E$ZY*UoWBd14zuh&}$$OcPzy9`n*L4T^TH3cCLFYHA^JbZ*PhMf~KWKsP
zQRjD1{{nmeMhpCiI)8xrXW07}THq(t`2p%Lu=h{cJD_DpIQ0yB|46;J>q9tn6P%0}
z#&dsx3m-bz-38bk@a%Aavv2V1177<L&wj&e-{IM}c<om_`xUSKfM?(1wO{b;7rgcp
zp8bf|e#Wz(@!CC}eZ*^D@azj-d%&|#c<nQueV*5Tx4yXL?PkLBN4&Z-dvaEnH@<Xv
zme??_pAUrKC}hB4hzHC#c#Jnk5#Bt;oulY(J;tk}2(KRF!BKSg9^=JPgcpzT<S4pF
zkMZm%!n4Qd9YuHa7#BwoE*@iW6y3>VoE=3tdyL6Zbfd@c6k&20dS8IA-QY1ih2#y+
z551#+3`q~1gOVOtAp@8p>46oJ9+)BNffX`<8Im4YA?bk`k{(zg1DGM{ffbS-m?7zb
z6*7Psy{9;OjEkp`ftm5C%vqY<zYOvcp8Lt;oIQmM_?+pgs)HD>tb9=VB`cN);h@X3
z+v(&jSIUZ=E)55DKqqVsx=gz<he}ydQ^{p&I=M_8beWn~SSkIQS}s%53oAvWgDz9k
z3@fEyQ_W>+x?!b=bkJpL+F_;iYwEd7O+Ty@kq)}d-c`!Laf^9zm7>x?mpQmf88~e*
z&#qEbI_NSdS1AMI7SmUXN(Vh={At(A6-Bz|DXaSDsbe0~(i2|^BHChFdSYde8^R5y
zr6*RV^z?jMdSYcvPuHiVCswBP^q7{OSQ*pPWm<Y-WlB$vY3YfTF+E*ouN#k*DLp;r
z#aG7kbeV&%OzG({&%QFIr^}ptWlB$vxuJ~d=`mw^dV6cB;xR2)tc<1AW5)Ev%9NfC
zGo~k2#`N@<F+H&|R!{GJD5fV?TJ?0_hhlnSWvreaGo~k2TJ?09F+H&|R!@%^(-SML
zdb-Sh<4TCt(_>yXlvX`m=CGlR)zf31H<VUAUFNi*jMdX)ZYiyLdd!rb_*CrX)~%m0
zSgf==Uyqs66Dwo&bbO}t#L6^?Yj#RcthAe3&u2<ctW1NLnbH$0?dH~Fru4+hG>Dlg
zJ+abmZarp7PpnLXnAvY#2}j{+gEwfGEoB;<nP19Wy;}7*cz5qV{4C$P&-6i>xt_Os
zfT)v2;ly#aRh&D3G}s)+l;ZgBz*A@=BhW3Fol*o76ojv25$(U1uXkxLKbPm)-s{7B
z87=>o#Du28heVpsdy}Lg>>{l_Q6vp*Ar<dGn<1KT_M}*CX)`v3nYR|A3HJ~+vc+TZ
zezzH_31{N`uTjk&TZoy*7GmacP6H;?%%fiR+8AMWjxEH@V+&CuTh4KQ!h~wV`5Yhh
zl{7|}d2AtO9$SbS*$nD>eI<<vRp&j;9*_D;8Y9d+_9kl(?jb5;@i;UPO*j)z4Z_T0
z3o$##7NUikBJ8I0ggFiq&K}1GVdk-gn0ag=TBs?)ST^NFv&WEDV1${+xdhX~c~@JA
zxyStHXTEj>4O|)>YMd^Q4aDpmTZjr<^07<hiV4+(%dVz!#R&6rY#`<y8;H5bRIZp%
zbC0Q9F~Zzq12Om5K+HX+6J<ipJ*INS2y>4O#N1;8G56T(OD?T+-cldKQD1Vx++%M#
zK9QH~Xdo)$nvVldG~q%#@xt6=12I3x2BL);1C+-pK4UI9oq0XSkr(D3r$*tjs|`d&
zT+cC;t9Fl}G1NF+AJuZhMZS1!ASz(xF_x<x9veedY-~I+zgAO$q(hx~@;erLN(-;M
z8p{<U%&*l3V&Rb|s;AXC#&X4kYQn3>Sgsgh;gKg69(iKnG1_H9Ej-3@#Rv<JJhAY|
z6AO>MzNV^`&bz*^rUJRcW3LNQ#KPl|7V5;+wK}v3uh;5{78d8o6AO<#QA1mKob)xd
zt2%FWj-$S&goVecO?cf^o~VSC$5^hIOU{H>VrUE1X2%Eh%x}&fq5{?)tz7N#*cPf{
zQ=^H+wHgZ~9qNpe?^Ymb;c8c{TrtApTIGqQN1CYi*5_#DiV4+(E00#L7-8v=CYBy)
zV(HQRGNG0ptz0p}(j!eQJ<`O|W3L@ds3u&U<B=7X9{VQY9-@V+52+3MeUHZzD=a<I
z#PS?zqDHpP$4NW(cpO<_>5(Ru9%-URw)SWRa*xNb*CS0VJ<`O=qn4{(9yJ6;Se~Q(
zij@|w^3e(;Bdk1Xfux0NqLwR0Sb1cL)j6`n%A=MmCR7uyJ!-jPgq25@Sb1cLl}AlZ
zCe+HKmMcbBd1Q%|N0wN5?8#6~xIV`tDXcuQ#L6Q}v{3b7Zi75wjzj0KezpqXL<%d9
zLyK^|t1MC0&uhm-5>2=!j-;^i$P%k_WQi84J}ga^+I5aWR$zpcM=g-FaJ{Q6QLSb7
z09vjXq6sr%OQ@<|8cDRx*+W!N?orCsK95qa7-4;mB(e5L5^IlAu9#3wnC+^RD@Is*
zB#E_0l306`Q)NP}JxaM^gtbSKSbHRiwa1<dwf1=AgtbSKSbHRiwa0-Awf1=8gtbSK
zSbHRiwa1AIwe~o2!rCKAtUZ#%+M|>!Car3ZVXsG$SbHRiz~l0n8x8+I$KGJM&8g2(
zN;0#nz#~Tl9+%JlX!Ur@hpO0X<A}f`M^sRL4<P@Uo7q(pX7w@LQ$lc#91(crh`{6W
zStzaN__)_2M+6=@BJkK#p@MTfQbKT!91(crh`{4Og$g{LC?W935rIdJ2s}<ysKDb$
z34uqB2t0B`;BomQ#@2icdp&YQ;E^LDk2gEtSC`MY+T0v)jvYlr9_PO;+9V>6cY8hF
zGD75$A|j6z5qW%ILN#GtAHzK(L>?(3@<<Vp$0sIK<nfUaB99aid8CNQW6y+&JRTV#
z@<<VpM~a9%4os-X<B1U>j}#Gkq=?Al#Dt1Gj*Jj_q=?AlO#E8H(Q*Cwo=?)>JAR=d
lO6&E({^(Jk%uQ!&V?x$>+3(BseJBYx$qM;jWL=;l{|g9#Ikf-)

literal 0
HcmV?d00001

diff --git a/tests/extern.ml b/tests/extern.ml
new file mode 100644
index 0000000..33819a8
--- /dev/null
+++ b/tests/extern.ml
@@ -0,0 +1,14 @@
+(* Marshal some interesting big integers to the given file *)
+
+let _ =
+  let file = Sys.argv.(1) in
+  let oc = open_out_bin file in
+  for nbits = 2 to 128 do
+    let x = Z.shift_left Z.one nbits in
+    output_value oc x;
+    output_value oc (Z.pred x);
+    output_value oc (Z.neg x);
+    output_value oc (Z.neg (Z.pred x))
+  done;
+  close_out oc
+
diff --git a/tests/intern.ml b/tests/intern.ml
new file mode 100644
index 0000000..cd359c2
--- /dev/null
+++ b/tests/intern.ml
@@ -0,0 +1,24 @@
+(* Unmarshal big integers from the given file, and report errors *)
+
+open Printf
+
+let expect ic n =
+  try
+    let m = (input_value ic : Z.t) in
+    if Z.equal m n then printf " OK" else printf " Wrong"
+  with Failure _ ->
+    printf " Fail"
+
+let _ =
+  let file = Sys.argv.(1) in
+  let ic = open_in_bin file in
+  for nbits = 2 to 128 do
+    printf "%d:" nbits;
+    let x = Z.shift_left Z.one nbits in
+    expect ic x;
+    expect ic (Z.pred x);
+    expect ic (Z.neg x);
+    expect ic (Z.neg (Z.pred x));
+    print_newline()
+  done;
+  close_in ic
diff --git a/tests/intern.output3232 b/tests/intern.output3232
new file mode 100644
index 0000000..b2c34a1
--- /dev/null
+++ b/tests/intern.output3232
@@ -0,0 +1,127 @@
+2: OK OK OK OK
+3: OK OK OK OK
+4: OK OK OK OK
+5: OK OK OK OK
+6: OK OK OK OK
+7: OK OK OK OK
+8: OK OK OK OK
+9: OK OK OK OK
+10: OK OK OK OK
+11: OK OK OK OK
+12: OK OK OK OK
+13: OK OK OK OK
+14: OK OK OK OK
+15: OK OK OK OK
+16: OK OK OK OK
+17: OK OK OK OK
+18: OK OK OK OK
+19: OK OK OK OK
+20: OK OK OK OK
+21: OK OK OK OK
+22: OK OK OK OK
+23: OK OK OK OK
+24: OK OK OK OK
+25: OK OK OK OK
+26: OK OK OK OK
+27: OK OK OK OK
+28: OK OK OK OK
+29: OK OK OK OK
+30: OK OK OK OK
+31: OK OK OK OK
+32: OK OK OK OK
+33: OK OK OK OK
+34: OK OK OK OK
+35: OK OK OK OK
+36: OK OK OK OK
+37: OK OK OK OK
+38: OK OK OK OK
+39: OK OK OK OK
+40: OK OK OK OK
+41: OK OK OK OK
+42: OK OK OK OK
+43: OK OK OK OK
+44: OK OK OK OK
+45: OK OK OK OK
+46: OK OK OK OK
+47: OK OK OK OK
+48: OK OK OK OK
+49: OK OK OK OK
+50: OK OK OK OK
+51: OK OK OK OK
+52: OK OK OK OK
+53: OK OK OK OK
+54: OK OK OK OK
+55: OK OK OK OK
+56: OK OK OK OK
+57: OK OK OK OK
+58: OK OK OK OK
+59: OK OK OK OK
+60: OK OK OK OK
+61: OK OK OK OK
+62: OK OK OK OK
+63: OK OK OK OK
+64: OK OK OK OK
+65: OK OK OK OK
+66: OK OK OK OK
+67: OK OK OK OK
+68: OK OK OK OK
+69: OK OK OK OK
+70: OK OK OK OK
+71: OK OK OK OK
+72: OK OK OK OK
+73: OK OK OK OK
+74: OK OK OK OK
+75: OK OK OK OK
+76: OK OK OK OK
+77: OK OK OK OK
+78: OK OK OK OK
+79: OK OK OK OK
+80: OK OK OK OK
+81: OK OK OK OK
+82: OK OK OK OK
+83: OK OK OK OK
+84: OK OK OK OK
+85: OK OK OK OK
+86: OK OK OK OK
+87: OK OK OK OK
+88: OK OK OK OK
+89: OK OK OK OK
+90: OK OK OK OK
+91: OK OK OK OK
+92: OK OK OK OK
+93: OK OK OK OK
+94: OK OK OK OK
+95: OK OK OK OK
+96: OK OK OK OK
+97: OK OK OK OK
+98: OK OK OK OK
+99: OK OK OK OK
+100: OK OK OK OK
+101: OK OK OK OK
+102: OK OK OK OK
+103: OK OK OK OK
+104: OK OK OK OK
+105: OK OK OK OK
+106: OK OK OK OK
+107: OK OK OK OK
+108: OK OK OK OK
+109: OK OK OK OK
+110: OK OK OK OK
+111: OK OK OK OK
+112: OK OK OK OK
+113: OK OK OK OK
+114: OK OK OK OK
+115: OK OK OK OK
+116: OK OK OK OK
+117: OK OK OK OK
+118: OK OK OK OK
+119: OK OK OK OK
+120: OK OK OK OK
+121: OK OK OK OK
+122: OK OK OK OK
+123: OK OK OK OK
+124: OK OK OK OK
+125: OK OK OK OK
+126: OK OK OK OK
+127: OK OK OK OK
+128: OK OK OK OK
diff --git a/tests/intern.output3264 b/tests/intern.output3264
new file mode 100644
index 0000000..5327d0a
--- /dev/null
+++ b/tests/intern.output3264
@@ -0,0 +1,127 @@
+2: OK OK OK OK
+3: OK OK OK OK
+4: OK OK OK OK
+5: OK OK OK OK
+6: OK OK OK OK
+7: OK OK OK OK
+8: OK OK OK OK
+9: OK OK OK OK
+10: OK OK OK OK
+11: OK OK OK OK
+12: OK OK OK OK
+13: OK OK OK OK
+14: OK OK OK OK
+15: OK OK OK OK
+16: OK OK OK OK
+17: OK OK OK OK
+18: OK OK OK OK
+19: OK OK OK OK
+20: OK OK OK OK
+21: OK OK OK OK
+22: OK OK OK OK
+23: OK OK OK OK
+24: OK OK OK OK
+25: OK OK OK OK
+26: OK OK OK OK
+27: OK OK OK OK
+28: OK OK OK OK
+29: OK OK OK OK
+30: Fail OK OK OK
+31: Fail Fail Fail Fail
+32: Fail Fail Fail Fail
+33: Fail Fail Fail Fail
+34: Fail Fail Fail Fail
+35: Fail Fail Fail Fail
+36: Fail Fail Fail Fail
+37: Fail Fail Fail Fail
+38: Fail Fail Fail Fail
+39: Fail Fail Fail Fail
+40: Fail Fail Fail Fail
+41: Fail Fail Fail Fail
+42: Fail Fail Fail Fail
+43: Fail Fail Fail Fail
+44: Fail Fail Fail Fail
+45: Fail Fail Fail Fail
+46: Fail Fail Fail Fail
+47: Fail Fail Fail Fail
+48: Fail Fail Fail Fail
+49: Fail Fail Fail Fail
+50: Fail Fail Fail Fail
+51: Fail Fail Fail Fail
+52: Fail Fail Fail Fail
+53: Fail Fail Fail Fail
+54: Fail Fail Fail Fail
+55: Fail Fail Fail Fail
+56: Fail Fail Fail Fail
+57: Fail Fail Fail Fail
+58: Fail Fail Fail Fail
+59: Fail Fail Fail Fail
+60: Fail Fail Fail Fail
+61: Fail Fail Fail Fail
+62: OK Fail Fail Fail
+63: OK OK OK OK
+64: OK OK OK OK
+65: OK OK OK OK
+66: OK OK OK OK
+67: OK OK OK OK
+68: OK OK OK OK
+69: OK OK OK OK
+70: OK OK OK OK
+71: OK OK OK OK
+72: OK OK OK OK
+73: OK OK OK OK
+74: OK OK OK OK
+75: OK OK OK OK
+76: OK OK OK OK
+77: OK OK OK OK
+78: OK OK OK OK
+79: OK OK OK OK
+80: OK OK OK OK
+81: OK OK OK OK
+82: OK OK OK OK
+83: OK OK OK OK
+84: OK OK OK OK
+85: OK OK OK OK
+86: OK OK OK OK
+87: OK OK OK OK
+88: OK OK OK OK
+89: OK OK OK OK
+90: OK OK OK OK
+91: OK OK OK OK
+92: OK OK OK OK
+93: OK OK OK OK
+94: OK OK OK OK
+95: OK OK OK OK
+96: OK OK OK OK
+97: OK OK OK OK
+98: OK OK OK OK
+99: OK OK OK OK
+100: OK OK OK OK
+101: OK OK OK OK
+102: OK OK OK OK
+103: OK OK OK OK
+104: OK OK OK OK
+105: OK OK OK OK
+106: OK OK OK OK
+107: OK OK OK OK
+108: OK OK OK OK
+109: OK OK OK OK
+110: OK OK OK OK
+111: OK OK OK OK
+112: OK OK OK OK
+113: OK OK OK OK
+114: OK OK OK OK
+115: OK OK OK OK
+116: OK OK OK OK
+117: OK OK OK OK
+118: OK OK OK OK
+119: OK OK OK OK
+120: OK OK OK OK
+121: OK OK OK OK
+122: OK OK OK OK
+123: OK OK OK OK
+124: OK OK OK OK
+125: OK OK OK OK
+126: OK OK OK OK
+127: OK OK OK OK
+128: OK OK OK OK
diff --git a/tests/intern.output6432 b/tests/intern.output6432
new file mode 100644
index 0000000..5327d0a
--- /dev/null
+++ b/tests/intern.output6432
@@ -0,0 +1,127 @@
+2: OK OK OK OK
+3: OK OK OK OK
+4: OK OK OK OK
+5: OK OK OK OK
+6: OK OK OK OK
+7: OK OK OK OK
+8: OK OK OK OK
+9: OK OK OK OK
+10: OK OK OK OK
+11: OK OK OK OK
+12: OK OK OK OK
+13: OK OK OK OK
+14: OK OK OK OK
+15: OK OK OK OK
+16: OK OK OK OK
+17: OK OK OK OK
+18: OK OK OK OK
+19: OK OK OK OK
+20: OK OK OK OK
+21: OK OK OK OK
+22: OK OK OK OK
+23: OK OK OK OK
+24: OK OK OK OK
+25: OK OK OK OK
+26: OK OK OK OK
+27: OK OK OK OK
+28: OK OK OK OK
+29: OK OK OK OK
+30: Fail OK OK OK
+31: Fail Fail Fail Fail
+32: Fail Fail Fail Fail
+33: Fail Fail Fail Fail
+34: Fail Fail Fail Fail
+35: Fail Fail Fail Fail
+36: Fail Fail Fail Fail
+37: Fail Fail Fail Fail
+38: Fail Fail Fail Fail
+39: Fail Fail Fail Fail
+40: Fail Fail Fail Fail
+41: Fail Fail Fail Fail
+42: Fail Fail Fail Fail
+43: Fail Fail Fail Fail
+44: Fail Fail Fail Fail
+45: Fail Fail Fail Fail
+46: Fail Fail Fail Fail
+47: Fail Fail Fail Fail
+48: Fail Fail Fail Fail
+49: Fail Fail Fail Fail
+50: Fail Fail Fail Fail
+51: Fail Fail Fail Fail
+52: Fail Fail Fail Fail
+53: Fail Fail Fail Fail
+54: Fail Fail Fail Fail
+55: Fail Fail Fail Fail
+56: Fail Fail Fail Fail
+57: Fail Fail Fail Fail
+58: Fail Fail Fail Fail
+59: Fail Fail Fail Fail
+60: Fail Fail Fail Fail
+61: Fail Fail Fail Fail
+62: OK Fail Fail Fail
+63: OK OK OK OK
+64: OK OK OK OK
+65: OK OK OK OK
+66: OK OK OK OK
+67: OK OK OK OK
+68: OK OK OK OK
+69: OK OK OK OK
+70: OK OK OK OK
+71: OK OK OK OK
+72: OK OK OK OK
+73: OK OK OK OK
+74: OK OK OK OK
+75: OK OK OK OK
+76: OK OK OK OK
+77: OK OK OK OK
+78: OK OK OK OK
+79: OK OK OK OK
+80: OK OK OK OK
+81: OK OK OK OK
+82: OK OK OK OK
+83: OK OK OK OK
+84: OK OK OK OK
+85: OK OK OK OK
+86: OK OK OK OK
+87: OK OK OK OK
+88: OK OK OK OK
+89: OK OK OK OK
+90: OK OK OK OK
+91: OK OK OK OK
+92: OK OK OK OK
+93: OK OK OK OK
+94: OK OK OK OK
+95: OK OK OK OK
+96: OK OK OK OK
+97: OK OK OK OK
+98: OK OK OK OK
+99: OK OK OK OK
+100: OK OK OK OK
+101: OK OK OK OK
+102: OK OK OK OK
+103: OK OK OK OK
+104: OK OK OK OK
+105: OK OK OK OK
+106: OK OK OK OK
+107: OK OK OK OK
+108: OK OK OK OK
+109: OK OK OK OK
+110: OK OK OK OK
+111: OK OK OK OK
+112: OK OK OK OK
+113: OK OK OK OK
+114: OK OK OK OK
+115: OK OK OK OK
+116: OK OK OK OK
+117: OK OK OK OK
+118: OK OK OK OK
+119: OK OK OK OK
+120: OK OK OK OK
+121: OK OK OK OK
+122: OK OK OK OK
+123: OK OK OK OK
+124: OK OK OK OK
+125: OK OK OK OK
+126: OK OK OK OK
+127: OK OK OK OK
+128: OK OK OK OK
diff --git a/tests/intern.output6464 b/tests/intern.output6464
new file mode 100644
index 0000000..b2c34a1
--- /dev/null
+++ b/tests/intern.output6464
@@ -0,0 +1,127 @@
+2: OK OK OK OK
+3: OK OK OK OK
+4: OK OK OK OK
+5: OK OK OK OK
+6: OK OK OK OK
+7: OK OK OK OK
+8: OK OK OK OK
+9: OK OK OK OK
+10: OK OK OK OK
+11: OK OK OK OK
+12: OK OK OK OK
+13: OK OK OK OK
+14: OK OK OK OK
+15: OK OK OK OK
+16: OK OK OK OK
+17: OK OK OK OK
+18: OK OK OK OK
+19: OK OK OK OK
+20: OK OK OK OK
+21: OK OK OK OK
+22: OK OK OK OK
+23: OK OK OK OK
+24: OK OK OK OK
+25: OK OK OK OK
+26: OK OK OK OK
+27: OK OK OK OK
+28: OK OK OK OK
+29: OK OK OK OK
+30: OK OK OK OK
+31: OK OK OK OK
+32: OK OK OK OK
+33: OK OK OK OK
+34: OK OK OK OK
+35: OK OK OK OK
+36: OK OK OK OK
+37: OK OK OK OK
+38: OK OK OK OK
+39: OK OK OK OK
+40: OK OK OK OK
+41: OK OK OK OK
+42: OK OK OK OK
+43: OK OK OK OK
+44: OK OK OK OK
+45: OK OK OK OK
+46: OK OK OK OK
+47: OK OK OK OK
+48: OK OK OK OK
+49: OK OK OK OK
+50: OK OK OK OK
+51: OK OK OK OK
+52: OK OK OK OK
+53: OK OK OK OK
+54: OK OK OK OK
+55: OK OK OK OK
+56: OK OK OK OK
+57: OK OK OK OK
+58: OK OK OK OK
+59: OK OK OK OK
+60: OK OK OK OK
+61: OK OK OK OK
+62: OK OK OK OK
+63: OK OK OK OK
+64: OK OK OK OK
+65: OK OK OK OK
+66: OK OK OK OK
+67: OK OK OK OK
+68: OK OK OK OK
+69: OK OK OK OK
+70: OK OK OK OK
+71: OK OK OK OK
+72: OK OK OK OK
+73: OK OK OK OK
+74: OK OK OK OK
+75: OK OK OK OK
+76: OK OK OK OK
+77: OK OK OK OK
+78: OK OK OK OK
+79: OK OK OK OK
+80: OK OK OK OK
+81: OK OK OK OK
+82: OK OK OK OK
+83: OK OK OK OK
+84: OK OK OK OK
+85: OK OK OK OK
+86: OK OK OK OK
+87: OK OK OK OK
+88: OK OK OK OK
+89: OK OK OK OK
+90: OK OK OK OK
+91: OK OK OK OK
+92: OK OK OK OK
+93: OK OK OK OK
+94: OK OK OK OK
+95: OK OK OK OK
+96: OK OK OK OK
+97: OK OK OK OK
+98: OK OK OK OK
+99: OK OK OK OK
+100: OK OK OK OK
+101: OK OK OK OK
+102: OK OK OK OK
+103: OK OK OK OK
+104: OK OK OK OK
+105: OK OK OK OK
+106: OK OK OK OK
+107: OK OK OK OK
+108: OK OK OK OK
+109: OK OK OK OK
+110: OK OK OK OK
+111: OK OK OK OK
+112: OK OK OK OK
+113: OK OK OK OK
+114: OK OK OK OK
+115: OK OK OK OK
+116: OK OK OK OK
+117: OK OK OK OK
+118: OK OK OK OK
+119: OK OK OK OK
+120: OK OK OK OK
+121: OK OK OK OK
+122: OK OK OK OK
+123: OK OK OK OK
+124: OK OK OK OK
+125: OK OK OK OK
+126: OK OK OK OK
+127: OK OK OK OK
+128: OK OK OK OK