From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id F2BCF385624E; Sat, 23 Apr 2022 09:04:22 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F2BCF385624E From: "vwebber at msn dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c/105357] dereferenced ptr on param stack gets over written Date: Sat, 23 Apr 2022 09:04:22 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c X-Bugzilla-Version: 9.4.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: vwebber at msn dot com X-Bugzilla-Status: RESOLVED X-Bugzilla-Resolution: INVALID 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: 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: Sat, 23 Apr 2022 09:04:23 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105357 --- Comment #3 from vwebber --- Thank you for the comments.=20 However, the data being overwritten is on the stack in a function which is called after the problematic scanf() etc are are run. I would suggest running up GDB and do a break on access of the overwritten lvalue.=20=20 Regards,=20 Victor Webber V&T: 408-221-8467=20 V: 805-924-1953 vwebber@msn.com -----Original Message----- From: pinskia at gcc dot gnu.org =20 Sent: Saturday, April 23, 2022 1:07 AM To: vwebber@msn.com Subject: [Bug c/105357] dereferenced ptr on param stack gets over written https://nam12.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Fgcc.gnu= .org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D105357&data=3D05%7C01%7C%7Cccc94c= 12b24440504a1d08da25003521%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637= 862980067506332%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzI= iLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3DXv3EJ%2FCciXIGx= 8Y9sxvqo1rw9mcvMISwNFnGD5Dbowk%3D&reserved=3D0 Andrew Pinski changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED --- Comment #2 from Andrew Pinski --- You need better error checking in your code. scanf can fail and scanf with %s without a size can definitely have a buffer overflow. You might be able to detect some of this with -fsanitize=3Daddress or by us= ing valgrind. This is almost definitely not a bug in GCC. -- You are receiving this mail because: You reported the bug.=