Add a hidden __stack_chk_fail_local alias to libc.so, and make sure that on targets which use __stack_chk_fail, this does not introduce a local PLT reference into libc.so.
explicit_bzero(s, n) is the same as memset(s, 0, n), except that the compiler is not allowed to delete a call to explicit_bzero even if the memory pointed to by 's' is dead after the call. Right now, this effect is achieved externally by having explicit_bzero be a function whose semantics are unknown to the compiler, and internally, with a no-op asm statement that clobbers memory. This does mean that small explicit_bzero operations cannot be expanded inline as small memset operations can, but on the other hand, small memset operations do get deleted by the compiler. Hopefully full compiler support for explicit_bzero will happen relatively soon. There are two new tests: test-explicit_bzero.c verifies the visible semantics in the same way as the existing test-bzero.c, and tst-xbzero-opt.c verifies the not-being-optimized-out property. The latter is conceptually based on a test written by Matthew Dempsky for the OpenBSD regression suite. The crypt() implementation has an immediate use for this new feature. We avoid having to add a GLIBC_PRIVATE alias for explicit_bzero by running all of libcrypt's calls through the fortified variant, __explicit_bzero_chk, which is in the impl namespace anyway. Currently I'm not aware of anything in libc proper that needs this, but the glue is all in place if it does become necessary. The legacy DES implementation wasn't bothering to clear its buffers, so I added that, mostly for consistency's sake. * string/explicit_bzero.c: New routine. * string/test-explicit_bzero.c, string/tst-xbzero-opt.c: New tests. * string/Makefile (routines, strop-tests, tests): Add them. * string/test-memset.c: Add ifdeffage for testing explicit_bzero. * string/string.h [__USE_MISC]: Declare explicit_bzero. * debug/explicit_bzero_chk.c: New routine. * debug/Makefile (routines): Add it. * debug/tst-chk1.c: Test fortification of explicit_bzero. * string/bits/string3.h: Fortify explicit_bzero. * manual/string.texi: Document explicit_bzero. * NEWS: Mention addition of explicit_bzero. * crypt/crypt-entry.c (__crypt_r): Clear key-dependent intermediate data before returning, using explicit_bzero. * crypt/md5-crypt.c (__md5_crypt_r): Likewise. * crypt/sha256-crypt.c (__sha256_crypt_r): Likewise. * crypt/sha512-crypt.c (__sha512_crypt_r): Likewise. * include/string.h: Redirect internal uses of explicit_bzero to __explicit_bzero_chk[_internal]. * string/Versions [GLIBC_2.25]: Add explicit_bzero. * debug/Versions [GLIBC_2.25]: Add __explicit_bzero_chk. * sysdeps/arm/nacl/libc.abilist * sysdeps/unix/sysv/linux/aarch64/libc.abilist * sysdeps/unix/sysv/linux/alpha/libc.abilist * sysdeps/unix/sysv/linux/arm/libc.abilist * sysdeps/unix/sysv/linux/hppa/libc.abilist * sysdeps/unix/sysv/linux/i386/libc.abilist * sysdeps/unix/sysv/linux/ia64/libc.abilist * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist * sysdeps/unix/sysv/linux/microblaze/libc.abilist * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist * sysdeps/unix/sysv/linux/nios2/libc.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist * sysdeps/unix/sysv/linux/sh/libc.abilist * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist * sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist * sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Add entries for explicit_bzero and __explicit_bzero_chk.
There is a configure test for -fexceptions. This option was added in GCC 2.8, so the test is obsolete - and indeed plenty of code is using -fexceptions directly. This patch removes the configure test and makes all uses of $(exceptions) use -fexceptions directly. Tested for x86_64 and x86 (testsuite, and that installed shared libraries are unchanged by the patch). * configure.ac (libc_cv_gcc_exceptions): Remove configure test. * configure: Regenerated. * sysdeps/arm/configure.ac (libc_cv_gcc_exceptions): Do not set variable. (exceptions): Likewise. * sysdeps/arm/configure: Regenerated. * config.make.in (exceptions): Remove variable. * Makeconfig (uses-callbacks): Use -fexceptions instead of $(exceptions). * debug/Makefile (CFLAGS-dprintf_chk.c): Likewise. (CFLAGS-vdprintf_chk.c): Likewise. (CFLAGS-printf_chk.c): Likewise. (CFLAGS-fprintf_chk.c): Likewise. (CFLAGS-vprintf_chk.c): Likewise. (CFLAGS-vfprintf_chk.c): Likewise. (CFLAGS-gets_chk.c): Likewise. (CFLAGS-fgets_chk.c): Likewise. (CFLAGS-fgets_u_chk.c): Likewise. (CFLAGS-fread_chk.c): Likewise. (CFLAGS-fread_u_chk.c): Likewise. (CFLAGS-wprintf_chk.c): Likewise. (CFLAGS-fwprintf_chk.c): Likewise. (CFLAGS-vwprintf_chk.c): Likewise. (CFLAGS-vfwprintf_chk.c): Likewise. (CFLAGS-fgetws_chk.c): Likewise. (CFLAGS-fgetws_u_chk.c): Likewise. * libio/Makefile (CFLAGS-fileops.c): Likewise. (CFLAGS-fputc.c): Likewise. (CFLAGS-fputwc.c): Likewise. (CFLAGS-freopen64.c): Likewise. (CFLAGS-freopen.c): Likewise. (CFLAGS-fseek.c): Likewise. (CFLAGS-fseeko64.c): Likewise. (CFLAGS-fseeko.c): Likewise. (CFLAGS-ftello64.c): Likewise. (CFLAGS-ftello.c): Likewise. (CFLAGS-fwide.c): Likewise. (CFLAGS-genops.c): Likewise. (CFLAGS-getc.c): Likewise. (CFLAGS-getchar.c): Likewise. (CFLAGS-getwc.c): Likewise. (CFLAGS-getwchar.c): Likewise. (CFLAGS-iofclose.c): Likewise. (CFLAGS-iofflush.c): Likewise. (CFLAGS-iofgetpos64.c): Likewise. (CFLAGS-iofgetpos.c): Likewise. (CFLAGS-iofgets.c): Likewise. (CFLAGS-iofgetws.c): Likewise. (CFLAGS-iofputs.c): Likewise. (CFLAGS-iofputws.c): Likewise. (CFLAGS-iofread.c): Likewise. (CFLAGS-iofsetpos64.c): Likewise. (CFLAGS-iofsetpos.c): Likewise. (CFLAGS-ioftell.c): Likewise. (CFLAGS-iofwrite.c): Likewise. (CFLAGS-iogetdelim.c): Likewise. (CFLAGS-iogetline.c): Likewise. (CFLAGS-iogets.c): Likewise. (CFLAGS-iogetwline.c): Likewise. (CFLAGS-ioputs.c): Likewise. (CFLAGS-ioseekoff.c): Likewise. (CFLAGS-ioseekpos.c): Likewise. (CFLAGS-iosetbuffer.c): Likewise. (CFLAGS-iosetvbuf.c): Likewise. (CFLAGS-ioungetc.c): Likewise. (CFLAGS-ioungetwc.c): Likewise. (CFLAGS-oldfileops.c): Likewise. (CFLAGS-oldiofclose.c): Likewise. (CFLAGS-oldiofgetpos64.c): Likewise. (CFLAGS-oldiofgetpos.c): Likewise. (CFLAGS-oldiofsetpos64.c): Likewise. (CFLAGS-oldiofsetpos.c): Likewise. (CFLAGS-peekc.c): Likewise. (CFLAGS-putc.c): Likewise. (CFLAGS-putchar.c): Likewise. (CFLAGS-putwc.c): Likewise. (CFLAGS-putwchar.c): Likewise. (CFLAGS-rewind.c): Likewise. (CFLAGS-wfileops.c): Likewise. (CFLAGS-wgenops.c): Likewise. (CFLAGS-oldiofopen.c): Likewise. (CFLAGS-iofopen.c): Likewise. (CFLAGS-iofopen64.c): Likewise. (CFLAGS-oldtmpfile.c): Likewise. * stdio-common/Makefile (CFLAGS-vfprintf.c): Likewise. (CFLAGS-fprintf.c): Likewise. (CFLAGS-printf.c): Likewise. (CFLAGS-vfwprintf.c): Likewise. (CFLAGS-vfscanf.c): Likewise. (CFLAGS-vfwscanf.c): Likewise. (CFLAGS-fscanf.c): Likewise. (CFLAGS-scanf.c): Likewise. (CFLAGS-isoc99_vfscanf.c): Likewise. (CFLAGS-isoc99_vscanf.c): Likewise. (CFLAGS-isoc99_fscanf.c): Likewise. (CFLAGS-isoc99_scanf.c): Likewise. * wcsmbs/Makefile (CFLAGS-isoc99_wscanf.c): Likewise. (CFLAGS-isoc99_fwscanf.c): Likewise. (CFLAGS-isoc99_vwscanf.c): Likewise. (CFLAGS-isoc99_vfwscanf.c): Likewise.
As discussed starting at <https://sourceware.org/ml/libc-alpha/2014-11/msg00323.html>, this patch makes the glibc build use -Werror by default to avoid accidentally adding new warnings to the build. The configure option --disable-werror can be used to disable this. -Wno-error=undef is temporarily used because the build isn't clean regarding -Wundef warnings. The idea is that once the remaining -Wundef warnings have been cleaned up (in at least one configuration), -Wno-error=undef will be removed. I get a clean build and test on x86_64 (GCC 4.9 branch) with this patch. The expectation is that this may well break the build for some other configurations, and people seeing such breakage should make appropriate fixes to fix or suppress the warnings for their configurations. In some cases that may involve using pragmas as the right fix (I think that will be right for the -Wno-inline issue for MIPS I referred to in <https://sourceware.org/ml/libc-alpha/2012-11/msg00798.html>, for example), in some cases -Wno-error in sysdeps makefiles (__restore_rt in MIPS sigaction, for example), in some cases substantive fixes for the warnings. Note that if, with a view to listing all the warnings then fixing them all, you just look for "warning:" in output from building and testing with --disable-werror, you'll see lots of warnings from the linker about functions such as tmpnam. Those warnings can be ignored - only compiler warnings are relevant to -Werror, not linker warnings. * configure.ac (--disable-werror): New configure option. (enable_werror): New AC_SUBST. * configure: Regenerated. * config.make.in (enable-werror): New variable. * Makeconfig [$(enable-werror) = yes] (+gccwarn): Add -Werror -Wno-error=undef. (+gccwarn-c): Do not use -Werror=implicit-function-declaration. * manual/install.texi (Configuring and compiling): Document --disable-werror. * INSTALL: Regenerated. * debug/Makefile (CFLAGS-tst-chk1.c): Add -Wno-error. (CFLAGS-tst-chk2.c): Likewise. (CFLAGS-tst-chk3.c): Likewise. (CFLAGS-tst-chk4.cc): Likewise. (CFLAGS-tst-chk5.cc): Likewise. (CFLAGS-tst-chk6.cc): Likewise. (CFLAGS-tst-lfschk1.c): Likewise. (CFLAGS-tst-lfschk2.c): Likewise. (CFLAGS-tst-lfschk3.c): Likewise. (CFLAGS-tst-lfschk4.cc): Likewise. (CFLAGS-tst-lfschk5.cc): Likewise. (CFLAGS-tst-lfschk6.cc): Likewise.