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Date:      Tue, 18 Jan 2022 13:03:46 +0000 (UTC)
From:      Sagara Wijetunga <sagarawmw@yahoo.com>
To:        "freebsd-questions@FreeBSD.org" <freebsd-questions@FreeBSD.org>
Subject:   How to disable clang AddressSanitizer instrumentation for a function on FreeBSD?
Message-ID:  <366091554.1057409.1642511026145@mail.yahoo.com>
References:  <366091554.1057409.1642511026145.ref@mail.yahoo.com>
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Hi=C2=A0
I'm trying to skip=C2=A0clang AddressSanitizer instrumentation for=C2=A0isM=
atch(void *ptr) function. How to do this on FreeBSD?=C2=A0
My test program:
#include <string.h>#include <stdio.h>#include <stdlib.h>
=C2=A0#define=C2=A0 PATTERN1=C2=A0 =C2=A00x4ffcf694=C2=A0static unsigned ch=
ar pattern1[] =3D {0x4f,0xfc,0xf6,0x94};

__attribute__((no_sanitize("address")))=C2=A0int isMatch(void *ptr);
int main(int argc, char *argv[]){=C2=A0int rv =3D 0;=C2=A0void *ptr =3D NUL=
L;
=C2=A0ptr =3D malloc(4);=C2=A0if (!ptr)=C2=A0 =C2=A0 {=C2=A0 =C2=A0 =C2=A0p=
rintf("No memory.");=C2=A0 =C2=A0 =C2=A0exit(1);=C2=A0 =C2=A0 }=C2=A0=C2=A0=
/* Copy PATTERN1 marker to the allocated block */=C2=A0memcpy(ptr, pattern1=
, sizeof(pattern1));
=C2=A0/*=C2=A0 TEST 1: Correct case.=C2=A0*/=C2=A0printf("TEST 1: Correct c=
ase.\n");=C2=A0rv =3D isMatch(ptr);=C2=A0if (rv =3D=3D 1)=C2=A0 =C2=A0 prin=
tf("Matched\n");=C2=A0else=C2=A0 =C2=A0 printf("NOT Matched\n");

=C2=A0/*=C2=A0 TEST 2: ptr - 1000=C2=A0*/=C2=A0printf("TEST 2: ptr - 1000\n=
");=C2=A0rv =3D isMatch(ptr - 1000);=C2=A0if (rv =3D=3D 1)=C2=A0 =C2=A0 pri=
ntf("Matched\n");=C2=A0else=C2=A0 =C2=A0 printf("NOT Matched\n");
}
__attribute__((no_sanitize("address")))=C2=A0int isMatch(void *ptr){=C2=A0i=
f ((memcmp(ptr, (void *)pattern1, sizeof(pattern1)) =3D=3D 0))=C2=A0 =C2=A0=
 return 1;=C2=A0=C2=A0return 0;}

/usr/local/bin/clang13 prog.c -O1 -g -fsanitize=3Daddress -fno-omit-frame-p=
ointer -Wall -O -I. -I/usr/local/include -L. -L/usr/local/lib -o prog

When run I get following:./progTEST 1: Correct case.MatchedTEST 2: ptr - 10=
00AddressSanitizer:DEADLYSIGNAL=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D29072=3D=3DERROR: AddressSanitizer: SEGV on unknown address 0x601f=
fff00010 (pc 0x0000002bb794 bp 0x7fffffffea30 sp 0x7fffffffea30 T0)=3D=3D29=
072=3D=3DThe signal is caused by a READ memory access.=C2=A0 =C2=A0 #0 0x2b=
b794 in isMatch path/prog.c:67:7=C2=A0 =C2=A0 #1 0x2bb73e in main path/prog=
.c:56:7=C2=A0 =C2=A0 #2 0x236d3f in _start /usr/src/lib/csu/amd64/crt1_c.c:=
75:7=C2=A0 =C2=A0 #3 0x8002e2007=C2=A0 (<unknown module>)
AddressSanitizer can not provide additional info.SUMMARY: AddressSanitizer:=
 SEGV path/prog.c:67:7 in isMatch=3D=3D29072=3D=3DABORTING
Appreciate any help.
Best regardsSagara
=C2=A0


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<html><head></head><body><div class=3D"yahoo-style-wrap" style=3D"font-fami=
ly:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir=
=3D"ltr" data-setdir=3D"false">Hi&nbsp;</div><div dir=3D"ltr" data-setdir=
=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">I'm trying to s=
kip&nbsp;<span>clang AddressSanitizer instrumentation for&nbsp;<span>isMatc=
h(void *ptr) function. How to do this on FreeBSD?&nbsp;</span></span></div>=
<div dir=3D"ltr" data-setdir=3D"false"><span><span><br></span></span></div>=
<div dir=3D"ltr" data-setdir=3D"false">My test program:</div><div dir=3D"lt=
r" data-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false"><=
div><div>#include &lt;string.h&gt;</div><div>#include &lt;stdio.h&gt;</div>=
<div>#include &lt;stdlib.h&gt;</div><div><br></div><div>&nbsp;#define&nbsp;=
 PATTERN1&nbsp; &nbsp;0x4ffcf694</div><div>&nbsp;static unsigned char patte=
rn1[] =3D {0x4f,0xfc,0xf6,0x94};</div><div><br></div><div><br></div><div>__=
attribute__((no_sanitize("address")))&nbsp;</div><div>int isMatch(void *ptr=
);</div><div><br></div><div>int main(int argc, char *argv[])</div><div>{</d=
iv><div>&nbsp;int rv =3D 0;</div><div>&nbsp;void *ptr =3D NULL;</div><div><=
br></div><div>&nbsp;ptr =3D malloc(4);</div><div>&nbsp;if (!ptr)</div><div>=
&nbsp; &nbsp; {</div><div>&nbsp; &nbsp; &nbsp;printf("No memory.");</div><d=
iv>&nbsp; &nbsp; &nbsp;exit(1);</div><div>&nbsp; &nbsp; }</div><div>&nbsp;<=
/div><div>&nbsp;/* Copy PATTERN1 marker to the allocated block */</div><div=
>&nbsp;memcpy(ptr, pattern1, sizeof(pattern1));</div><div><br></div><div>&n=
bsp;/*</div><div>&nbsp; TEST 1: Correct case.</div><div>&nbsp;*/</div><div>=
&nbsp;printf("TEST 1: Correct case.\n");</div><div>&nbsp;rv =3D isMatch(ptr=
);</div><div>&nbsp;if (rv =3D=3D 1)</div><div>&nbsp; &nbsp; printf("Matched=
\n");</div><div>&nbsp;else</div><div>&nbsp; &nbsp; printf("NOT Matched\n");=
</div><div><br></div><div><br></div><div>&nbsp;/*</div><div>&nbsp; TEST 2: =
ptr - 1000</div><div>&nbsp;*/</div><div>&nbsp;printf("TEST 2: ptr - 1000\n"=
);</div><div>&nbsp;rv =3D isMatch(ptr - 1000);</div><div>&nbsp;if (rv =3D=
=3D 1)</div><div>&nbsp; &nbsp; printf("Matched\n");</div><div>&nbsp;else</d=
iv><div>&nbsp; &nbsp; printf("NOT Matched\n");</div><div><br></div><div>}</=
div><div><br></div><div>__attribute__((no_sanitize("address")))&nbsp;</div>=
<div>int isMatch(void *ptr)</div><div>{</div><div>&nbsp;if ((memcmp(ptr, (v=
oid *)pattern1, sizeof(pattern1)) =3D=3D 0))</div><div>&nbsp; &nbsp; return=
 1;</div><div>&nbsp;</div><div>&nbsp;return 0;</div><div>}</div><div><br></=
div></div><div><br></div></div><div dir=3D"ltr" data-setdir=3D"false"><span=
>/usr/local/bin/clang13 prog.c -O1 -g -fsanitize=3Daddress -fno-omit-frame-=
pointer -Wall -O -I. -I/usr/local/include -L. -L/usr/local/lib -o prog</spa=
n></div><div dir=3D"ltr" data-setdir=3D"false"><span><br></span></div><div =
dir=3D"ltr" data-setdir=3D"false"><span><br></span></div><div dir=3D"ltr" d=
ata-setdir=3D"false"><span>When run I get following:</span></div><div dir=
=3D"ltr" data-setdir=3D"false"><div><div>./prog</div><div>TEST 1: Correct c=
ase.</div><div>Matched</div><div>TEST 2: ptr - 1000</div><div>AddressSaniti=
zer:DEADLYSIGNAL</div><div>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D</d=
iv><div>=3D=3D29072=3D=3DERROR: AddressSanitizer: SEGV on unknown address 0=
x601ffff00010 (pc 0x0000002bb794 bp 0x7fffffffea30 sp 0x7fffffffea30 T0)</d=
iv><div>=3D=3D29072=3D=3DThe signal is caused by a READ memory access.</div=
><div>&nbsp; &nbsp; #0 0x2bb794 in isMatch path/prog.c:67:7</div><div>&nbsp=
; &nbsp; #1 0x2bb73e in main path/prog.c:56:7</div><div>&nbsp; &nbsp; #2 0x=
236d3f in _start /usr/src/lib/csu/amd64/crt1_c.c:75:7</div><div>&nbsp; &nbs=
p; #3 0x8002e2007&nbsp; (&lt;unknown module&gt;)</div><div><br></div><div>A=
ddressSanitizer can not provide additional info.</div><div>SUMMARY: Address=
Sanitizer: SEGV path/prog.c:67:7 in isMatch</div><div>=3D=3D29072=3D=3DABOR=
TING</div><div><br></div></div><div dir=3D"ltr" data-setdir=3D"false">Appre=
ciate any help.</div><div dir=3D"ltr" data-setdir=3D"false"><br></div><div =
dir=3D"ltr" data-setdir=3D"false">Best regards</div><div dir=3D"ltr" data-s=
etdir=3D"false">Sagara</div><div dir=3D"ltr" data-setdir=3D"false"><br></di=
v></div><div dir=3D"ltr" data-setdir=3D"false"><span>&nbsp;</span><br></div=
><div dir=3D"ltr" data-setdir=3D"false"><br></div></div></body></html>
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