Date: Fri, 4 Feb 2022 17:34:13 -0800 From: Mark Millard <marklmi@yahoo.com> To: bob prohaska <fbsd@www.zefox.net> Cc: freebsd-arm@freebsd.org Subject: Re: Troubles building world on stable/13 [How to set just the compiler to avoid ASLR being enabled for it] Message-ID: <0E1C03AD-7600-4680-A27A-985E6DC64B0C@yahoo.com> In-Reply-To: <51D494E4-6D8D-49C7-8F0C-FD53311264A5@yahoo.com> References: <20220124165449.GA39982@www.zefox.net> <5FAC2B2C-7740-435E-A183-FB3EF1FCE7F9@yahoo.com> <20220202223208.GA78110@www.zefox.net> <70550346-BC53-458F-B01B-68559E5C9847@yahoo.com> <20220203015149.GA78722@www.zefox.net> <8A85F917-F4E8-4382-B777-15AF7401E616@yahoo.com> <D93232D9-BCBF-4C65-B984-D95CB12ADFCD@yahoo.com> <C3D8ABCB-C7CC-4D88-B648-7C31C5BCC96E@yahoo.com> <20220204214403.GA85107@www.zefox.net> <B5FD0DF9-283E-49F1-BF73-2D8675B3E72E@yahoo.com> <20220205000800.GA85644@www.zefox.net> <51D494E4-6D8D-49C7-8F0C-FD53311264A5@yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
The following shows how to examine and control the compiler's ASLR status (notation shown presumes first cd'ing to where the c++ file is): # elfctl c++ File 'c++' features: noaslr 'Disable ASLR' is unset. noprotmax 'Disable implicit PROT_MAX' is unset. nostackgap 'Disable stack gap' is unset. wxneeded 'Requires W+X mappings' is unset. la48 'amd64: Limit user VA to 48bit' is unset. noaslrstkgap 'Disable ASLR stack gap' is unset. # elfctl -e +noaslr c++ # elfctl c++ File 'c++' features: noaslr 'Disable ASLR' is set. noprotmax 'Disable implicit PROT_MAX' is unset. nostackgap 'Disable stack gap' is unset. wxneeded 'Requires W+X mappings' is unset. la48 'amd64: Limit user VA to 48bit' is unset. noaslrstkgap 'Disable ASLR stack gap' is unset. (noaslrstkgap may be fairly specific to the vintage of main [so: 14] that I'm at and so might not show up.) Being tied to the file, this survives reboots. This should avoid needing the system wide disable that I'd previously listed. In other words: no need for: # sysctl kern.elf64.aslr.enable=0 (which would not survive a reboot). === Mark Millard marklmi at yahoo.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?0E1C03AD-7600-4680-A27A-985E6DC64B0C>