search for: mindirect

Displaying 20 results from an estimated 28 matches for "mindirect".

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2018 Feb 07
2
retpoline mitigation and 6.0
...s pushed onto the > stack? What are the semantics? Is there a spec anywheere? > > LLVM only needs this on 32-bit x86, but we do kind of need an answer > before we update all of our branches with new names.... That would be __x86_indirect_thunk but the kernel doesn't use it. We use -mindirect-branch-register and only ever expect the compiler to use the register versions which are CET-compatible. However, in at least one case in the 32-bit kernel we do emit the old ret-equivalent retpoline inline, because there literally wasn't a single register we could use (yay x86). I would defini...
2018 Feb 07
3
retpoline mitigation and 6.0
On Wed, 2018-02-07 at 00:36 +0000, Chandler Carruth wrote: > > > > That would be __x86_indirect_thunk but the kernel doesn't use it. > > We use -mindirect-branch-register and only ever expect the compiler > > to use the register versions which are CET-compatible. > > > > However, in at least one case in the 32-bit kernel we do emit the > > old ret-equivalent retpoline inline, because there literally wasn't > > a sin...
2018 Feb 07
2
retpoline mitigation and 6.0
...Feb 6, 2018 at 4:46 PM David Woodhouse <dwmw2 at infradead.org> > wrote: > >> On Wed, 2018-02-07 at 00:36 +0000, Chandler Carruth wrote: >> >> > > >> > > That would be __x86_indirect_thunk but the kernel doesn't use it. >> > > We use -mindirect-branch-register and only ever expect the compiler >> > > to use the register versions which are CET-compatible. >> > > >> > > However, in at least one case in the 32-bit kernel we do emit the >> > > old ret-equivalent retpoline inline, because there l...
2018 Jun 07
2
vanilla build of 7.7p1 release on linux/4.17 fails with gcc8 @ "/usr/bin/ld: unrecognized option '-Wl,-z,retpolineplt'"
...Host: x86_64-pc-linux-gnu Compiler: /usr/bin/gcc-8 Compiler flags: -g -O2 -pipe -Wall -Wpointer-arith -Wuninitialized -Wsign-compare -Wformat-security -Wsizeof-pointer-memaccess -Wno-pointer-sign -Wno-unused-result -fno-strict-aliasing -mfunction-return=thunk -mindirect-branch=thunk -D_FORTIFY_SOURCE=2 -ftrapv -fno-builtin-memset -fstack-protector-strong -fPIE Preprocessor flags: -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -D_DEFAULT_SOURCE Linker flags: -Wl,-z,retpolineplt -Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -fstack-protector-strong -pie Libra...
2018 Feb 07
0
retpoline mitigation and 6.0
...tack? > What are the semantics? Is there a spec anywheere? > > LLVM only needs this on 32-bit x86, but we do kind of need an answer > before we update all of our branches with new names.... > > > That would be __x86_indirect_thunk but the kernel doesn't use it. We use > -mindirect-branch-register and only ever expect the compiler to use the > register versions which are CET-compatible. > > However, in at least one case in the 32-bit kernel we do emit the old > ret-equivalent retpoline inline, because there literally wasn't a single > register we could use...
2018 Jun 08
2
vanilla build of 7.7p1 release on linux/4.17 fails with gcc8 @ "/usr/bin/ld: unrecognized option '-Wl,-z,retpolineplt'"
On Thu, Jun 07, 2018 at 06:14:42PM -0700, PGNet Dev wrote: > On 6/7/18 6:08 PM, Darren Tucker wrote: > > Well the intent is you should be able to set CC and LD to whatever you > > want as long as they work. In this case, the OSSH_CHECK_LDFLAG_LINK > > test invokes autoconf's AC_LINK_IFELSE with uses CC not LD. I'm not > > sure what to do about it yet
2018 Feb 07
0
retpoline mitigation and 6.0
On Tue, Feb 6, 2018 at 4:46 PM David Woodhouse <dwmw2 at infradead.org> wrote: > On Wed, 2018-02-07 at 00:36 +0000, Chandler Carruth wrote: > > > > > > > That would be __x86_indirect_thunk but the kernel doesn't use it. > > > We use -mindirect-branch-register and only ever expect the compiler > > > to use the register versions which are CET-compatible. > > > > > > However, in at least one case in the 32-bit kernel we do emit the > > > old ret-equivalent retpoline inline, because there literally wasn...
2018 Feb 07
0
retpoline mitigation and 6.0
...d Woodhouse <dwmw2 at infradead.org> >> wrote: >> >>> On Wed, 2018-02-07 at 00:36 +0000, Chandler Carruth wrote: >>> >>> > > >>> > > That would be __x86_indirect_thunk but the kernel doesn't use it. >>> > > We use -mindirect-branch-register and only ever expect the compiler >>> > > to use the register versions which are CET-compatible. >>> > > >>> > > However, in at least one case in the 32-bit kernel we do emit the >>> > > old ret-equivalent retpoline inline,...
2018 Aug 08
1
Reproducible SIGSEGV when Dovecot 2.3 compiled against glibc-2.28
...lure due to a segfault. It's the same crash Thore is seeing: /bin/sh ../../libtool --tag=CC --mode=link x86_64-pc-linux-gnu-gcc -std=gnu99 -O0 -g -pipe -march=native -mtune=native -ggdb -fstack-protector-strong -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -mfunction-return=thunk -mindirect-branch=thunk -Wall -W -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wformat=2 -Wbad-function-cast -fno-builtin-strftime -Wstrict-aliasing=2 -module -avoid-version -Wl,-O1 -Wl,--as-needed -o libauthdb_imap.la -rpath /usr/lib64/dovecot/auth libauthd...
2019 Jan 03
5
Compiling Dovecot on Solaris 11 fails
...no configure: error: fd passing is required for Dovecot to work .... config.log shows: configure:22538: checking whether shared mmaps get updated by write()s configure:22585: gcc -o conftest -std=gnu99 -g -O2 -fstack-protector-strong -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -mfunction-return=thunk -mindirect-branch=thunk -Wall -W -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wformat=2 -Wbad-function-cast -fno-builtin-strftime -Wstrict-aliasing=2?? conftest.c? >&5 configure:22585: $? = 0 configure:22585: ./conftest ./configure[2026]: eval: line 1: 29183...
2018 Sep 26
4
Concerns about enabling retpolines by default
We recently discovered that our OpenSSH distribution binaries contain retpoline thunks. It's due to this OSSH_CHECK_CFLAG_COMPILE([-mfunction-return=thunk]) # gcc OSSH_CHECK_CFLAG_COMPILE([-mindirect-branch=thunk]) # gcc This was quite surprising because at least the GNU/Linux userspace has no provisions for retpolines. You also fail to enable -fno-plt, so you need a special linker that produces non-standard PLT stubs. (And this has to be repeated for all system libraries you call.) In...
2018 Feb 07
0
retpoline mitigation and 6.0
On Tue, Feb 6, 2018 at 4:16 PM Chandler Carruth <chandlerc at google.com> wrote: > On Tue, Feb 6, 2018 at 2:56 PM David Woodhouse <dwmw2 at infradead.org> > wrote: > >> At this point, what we really want is for identical thunks to have >> identical names — just like we do for builtins and other stuff, to avoid >> having differences between clang and GCC
2018 Dec 04
2
Compilation error
...with-zlib --with-bzlib --with-libwrap --with-libcap --without-solr --without-gssapi --without-docs --without-sia --without-pgsql --without-lucene --without-stemmer THanks libtool: link: gcc -std=gnu99 -g -O2 -fstack-protector-strong -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -mfunction-return=thunk -mindirect-branch=thunk -Wall -W -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wformat=2 -Wbad-function-cast -fno-builtin-strftime -Wstrict-aliasing=2 -Wl,--as-needed -o test-lib test_lib-test-lib.o test_lib-test-array.o test_lib-test-aqueue.o test_lib-test-base32.o test_lib-t...
2018 Feb 07
4
retpoline mitigation and 6.0
On Tue, Feb 6, 2018 at 2:56 PM David Woodhouse <dwmw2 at infradead.org> wrote: > On Tue, 2018-02-06 at 22:08 +0000, Chandler Carruth wrote: > > So, I was waiting to hear a definitive response on whether using aliases > is hard, and didn't see one here, which is why I haven't responded further. > > However, a colleauge pointed me at an LKML thread where it seems
2018 Feb 05
2
add Spectre variant 2 mitigations
...;egcs"; then OSSH_CHECK_CFLAG_COMPILE([-Wunused-result], [-Wno-unused-result]) OSSH_CHECK_CFLAG_COMPILE([-fno-strict-aliasing]) if test "x$use_toolchain_hardening" = "x1"; then + OSSH_CHECK_CFLAG_COMPILE([-mfunction-return=thunk]) # gcc + OSSH_CHECK_CFLAG_COMPILE([-mindirect-branch=thunk]) # gcc + OSSH_CHECK_CFLAG_COMPILE([-mretpoline]) # clang + OSSH_CHECK_CFLAG_LINK([-z retpolineplt]) # clang OSSH_CHECK_CFLAG_COMPILE([-D_FORTIFY_SOURCE=2]) OSSH_CHECK_LDFLAG_LINK([-Wl,-z,relro]) OSSH_CHECK_LDFLAG_LINK([-Wl,-z,now]) -- Darren Tucker (dtucker at dtucker.net) GPG...
2018 Dec 04
0
Compilation error
...with-libcap --without-solr > --without-gssapi --without-docs --without-sia --without-pgsql > --without-lucene --without-stemmer > > THanks > > libtool: link: gcc -std=gnu99 -g -O2 -fstack-protector-strong > -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -mfunction-return=thunk > -mindirect-branch=thunk -Wall -W -Wmissing-prototypes > -Wmissing-declarations -Wpointer-arith -Wchar-subscripts -Wformat=2 > -Wbad-function-cast -fno-builtin-strftime -Wstrict-aliasing=2 > -Wl,--as-needed -o test-lib test_lib-test-lib.o test_lib-test-array.o > test_lib-test-aqueue.o test_lib-test...
2018 Jun 07
2
vanilla build of 7.7p1 release on linux/4.17 fails with gcc8 @ "/usr/bin/ld: unrecognized option '-Wl,-z,retpolineplt'"
hi On 6/7/18 4:03 PM, Darren Tucker wrote: > On 8 June 2018 at 07:09, PGNet Dev <pgnet.dev at gmail.com> wrote: >> Verifying a report I just got pinged about, building vanilla openssh 7.7p1 on linux configures ok, but fails build around 'retpoline' > [...] >> Should the retpoline flag be getting added? If so, what's needed to make LD happy with it?
2018 Jun 08
3
vanilla build of 7.7p1 release on linux/4.17 fails with gcc8 @ "/usr/bin/ld: unrecognized option '-Wl,-z,retpolineplt'"
One difference I notice is that in your failing example you are invoking /usr/bin/ld directly to link: /usr/bin/ld -o ssh ssh.o readconf.o clientloop.o sshtty.o sshconnect.o sshconnect2.o mux.o -L. -Lopenbsd-compat/ -Wl,-z,retpolineplt -Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -fstack-protector-strong -pie -lssh -lopenbsd-compat -lutil -lz -lcrypt
2018 Jun 08
4
vanilla build of 7.7p1 release on linux/4.17 fails with gcc8 @ "/usr/bin/ld: unrecognized option '-Wl,-z,retpolineplt'"
On 8 June 2018 at 10:52, PGNet Dev <pgnet.dev at gmail.com> wrote: [...] > So, there's a problem for OpenSSH build with spec'ing LD=/usr/bin/ld ? in this particular case, apparently yes. not generally, though. [...] > What's *intended* re: openssh? Support for LD=ld or only =gcc, or undef'd ? Well the intent is you should be able to set CC and LD to
2018 Feb 07
6
retpoline mitigation and 6.0
...radead.org> >>> wrote: >>> >>>> On Wed, 2018-02-07 at 00:36 +0000, Chandler Carruth wrote: >>>> >>>> > > >>>> > > That would be __x86_indirect_thunk but the kernel doesn't use it. >>>> > > We use -mindirect-branch-register and only ever expect the compiler >>>> > > to use the register versions which are CET-compatible. >>>> > > >>>> > > However, in at least one case in the 32-bit kernel we do emit the >>>> > > old ret-equivalent r...