From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 1EFD038708C7; Mon, 8 Mar 2021 09:15:25 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1EFD038708C7 From: "marxin at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug sanitizer/99418] sanitizer checks for accessing multidimentional VLA-array Date: Mon, 08 Mar 2021 09:15:25 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: sanitizer X-Bugzilla-Version: 10.2.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: marxin at gcc dot gnu.org X-Bugzilla-Status: WAITING X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cf_reconfirmed_on bug_status everconfirmed Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Mar 2021 09:15:26 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99418 Martin Li=C5=A1ka changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2021-03-08 Status|UNCONFIRMED |WAITING Ever confirmed|0 |1 --- Comment #3 from Martin Li=C5=A1ka --- > Surprisingly if I replace taking a reference with writing to the array it > will show an error. Yes, ASAN instruments memory reads and writes, so your test-case reports AS= AN errors with: void escape(int &a) { a =3D 123; } $ g++ pr99418.C -fsanitize=3Daddress && ./a.out=20 =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=3D7912=3D=3DERROR: AddressSanitizer: dynamic-stack-buffer-overflow on a= ddress 0x7fffffffde90 at pc 0x000000400869 bp 0x7fffffffde10 sp 0x7fffffffde08 WRITE of size 4 at 0x7fffffffde90 thread T0 #0 0x400868 in escape(int&) (/home/marxin/Programming/testcases/a.out+0x400868) #1 0x4009c0 in test(unsigned long, unsigned long) (/home/marxin/Programming/testcases/a.out+0x4009c0) #2 0x400a06 in main (/home/marxin/Programming/testcases/a.out+0x400a06) #3 0x7ffff708db24 in __libc_start_main (/lib64/libc.so.6+0x27b24) #4 0x40077d in _start (/home/marxin/Programming/testcases/a.out+0x40077= d) Address 0x7fffffffde90 is located in stack of thread T0 SUMMARY: AddressSanitizer: dynamic-stack-buffer-overflow (/home/marxin/Programming/testcases/a.out+0x400868) in escape(int&) Shadow bytes around the buggy address: 0x10007fff7b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7b90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7ba0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7bb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7bc0: 00 00 00 00 00 00 00 00 ca ca ca ca 00 00 00 00 =3D>0x10007fff7bd0: 00 00[cb]cb cb cb cb cb 00 00 00 00 00 00 00 00 0x10007fff7be0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7bf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7c10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7c20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07=20 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Shadow gap: cc =3D=3D7912=3D=3DABORTING That said, can we close it as resolved?=