alexhudson
115 lines
3.8 KiB
Plaintext
115 lines
3.8 KiB
Plaintext
dnl
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dnl Useful macros for autoconf to check for ssp-patched gcc
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dnl 1.0 - September 2003 - Tiago Sousa <mirage@kaotik.org>
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dnl 1.1 - August 2006 - Ted Percival <ted@midg3t.net>
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dnl * Stricter language checking (C or C++)
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dnl * Adds GCC_STACK_PROTECT_LIB to add -lssp to LDFLAGS as necessary
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dnl * Caches all results
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dnl * Uses macros to ensure correct ouput in quiet/silent mode
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dnl 1.2 - April 2007 - Ted Percival <ted@midg3t.net>
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dnl * Added GCC_STACK_PROTECTOR macro for simpler (one-line) invocation
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dnl * GCC_STACK_PROTECT_LIB now adds -lssp to LIBS rather than LDFLAGS
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dnl
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dnl About ssp:
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dnl GCC extension for protecting applications from stack-smashing attacks
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dnl http://www.research.ibm.com/trl/projects/security/ssp/
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dnl
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dnl Usage:
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dnl Most people will simply call GCC_STACK_PROTECTOR.
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dnl If you only use one of C or C++, you can save time by only calling the
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dnl macro appropriate for that language. In that case you should also call
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dnl GCC_STACK_PROTECT_LIB first.
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dnl
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dnl GCC_STACK_PROTECTOR
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dnl Tries to turn on stack protection for C and C++ by calling the following
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dnl three macros with the right languages.
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dnl
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dnl GCC_STACK_PROTECT_CC
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dnl checks -fstack-protector with the C compiler, if it exists then updates
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dnl CFLAGS and defines ENABLE_SSP_CC
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dnl
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dnl GCC_STACK_PROTECT_CXX
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dnl checks -fstack-protector with the C++ compiler, if it exists then updates
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dnl CXXFLAGS and defines ENABLE_SSP_CXX
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dnl
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dnl GCC_STACK_PROTECT_LIB
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dnl adds -lssp to LIBS if it is available
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dnl ssp is usually provided as part of libc, but was previously a separate lib
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dnl It does not hurt to add -lssp even if libc provides SSP - in that case
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dnl libssp will simply be ignored.
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dnl
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AC_DEFUN([GCC_STACK_PROTECT_LIB],[
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AC_CACHE_CHECK([whether libssp exists], ssp_cv_lib,
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[ssp_old_libs="$LIBS"
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LIBS="$LIBS -lssp"
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AC_TRY_LINK(,, ssp_cv_lib=yes, ssp_cv_lib=no)
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LIBS="$ssp_old_libs"
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])
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if test $ssp_cv_lib = yes; then
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LIBS="$LIBS -lssp"
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fi
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])
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AC_DEFUN([GCC_STACK_PROTECT_CC],[
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AC_LANG_ASSERT(C)
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if test "X$CC" != "X"; then
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AC_CACHE_CHECK([whether ${CC} accepts -fstack-protector],
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ssp_cv_cc,
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[ssp_old_cflags="$CFLAGS"
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CFLAGS="$CFLAGS -fstack-protector"
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AC_TRY_COMPILE(,, ssp_cv_cc=yes, ssp_cv_cc=no)
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CFLAGS="$ssp_old_cflags"
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])
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if test $ssp_cv_cc = yes; then
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CFLAGS="$CFLAGS -fstack-protector"
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AC_DEFINE([ENABLE_SSP_CC], 1, [Define if SSP C support is enabled.])
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fi
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fi
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])
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AC_DEFUN([GCC_STACK_PROTECT_CXX],[
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AC_LANG_ASSERT(C++)
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if test "X$CXX" != "X"; then
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AC_CACHE_CHECK([whether ${CXX} accepts -fstack-protector],
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ssp_cv_cxx,
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[ssp_old_cxxflags="$CXXFLAGS"
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CXXFLAGS="$CXXFLAGS -fstack-protector"
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AC_TRY_COMPILE(,, ssp_cv_cxx=yes, ssp_cv_cxx=no)
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CXXFLAGS="$ssp_old_cxxflags"
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])
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if test $ssp_cv_cxx = yes; then
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CXXFLAGS="$CXXFLAGS -fstack-protector"
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AC_DEFINE([ENABLE_SSP_CXX], 1, [Define if SSP C++ support is enabled.])
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fi
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fi
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])
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dnl By default, we don't enable unless we're on glibc 2.5 or better.
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dnl For some reason, linking on Debian etch (glibc=2.3, gcc=4.1) completely
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dnl fails unless -shared is in CCLD/CXXLD, but setting that flag causes
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dnl other configure tests to fail :( For now, I'm giving up on those
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dnl old versions since time will fix this bug for us (I hope!)
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AC_DEFUN([GCC_STACK_PROTECTOR],[
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dnl -lssp shouldn't even be needed on recent glibc/gcc
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dnl GCC_STACK_PROTECT_LIB
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AC_MSG_CHECKING([for GNU libc 2.4 or better])
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AC_EGREP_CPP(yes, [
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#include <features.h>
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#if __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 4
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yes
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#endif], [glibc_24=yes; AC_MSG_RESULT(yes)], AC_MSG_RESULT(no))
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if test "x$glibc_24" == "xyes"; then
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AC_LANG_PUSH([C])
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GCC_STACK_PROTECT_CC
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AC_LANG_POP([C])
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AC_LANG_PUSH([C++])
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GCC_STACK_PROTECT_CXX
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AC_LANG_POP([C++])
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fi
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])
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