Dominique Pelle wrote:
> 2008/11/16 Dominique Pelle <[EMAIL PROTECTED]>: > > > 2008/11/16 Bram Moolenaar <[EMAIL PROTECTED]>: > > > >> Apparently -fstack-protector is on by default. The "inline-functions" > >> apparently does something to reveal the size of the destination to > >> strcpy(). That's a bit unexpected though. > >> > >> Why not compile Vim with -fno-stack-protector ? Can you try with -O3 > >> and that flag? It's not clear to me that this stack-protector function > >> is what actually adds the check for the array size. > > > > Adding -fno-stack-protector does not help either (same warning + > > same crash). But reading through the man page of gcc, I stumbled > > upon this in the section about -O2: > > > > ================================================== > > NOTE: In Ubuntu 8.10 and later versions, -D_FORTIFY_SOURCE=2 > > is set by default, and is activated when -O is set to 2 or higher. > > This enables additional compile-time and run-time checks for several > > libc functions. To disable, specify either -U_FORTIFY_SOURCE or > > -D_FORTIFY_SOURCE=0. > > ================================================== > > > > So I tried adding compiling with -O3 -D_FORTIFY_SOURCE=0 > > and it makes it work! > > > > So far I don't observe anything wrong so fat with > > -O3 -D_FORTIFY_SOURCE=0. 'make test' succeeds > > in every tests. > > > > I'm not 100% sure whether adding -D_FORTIFY_SOURCE=0 silents > > a real bug, or whether it was reporting a spurious error (more likely > > from looking at vim code). But even if it silents a spurious bug in this > > case, adding -D_FORTIFY_SOURCE=0 may also silent other real > > bugs, which is a shame. I'll add the info to the gcc bug buzilla, but > > it was already and quickly marked as INVALID, so I don't expect > > much there. > > > > -- Dominique > > > I should add that building with -O3 -D_FORTIFY_SOURCE=1 also > works which is better. > > Reading about _FORTIFY_SOURCE in the following link, everything > makes sense now. > > Snippet from http://mail-index.netbsd.org/tech-userlevel/2007/05/23/0001.html > > =============================================== > The diffence between -D_FORTIFY_SOURCE=1 and -D_FORTIFY_SOURCE=2 > is e.g. for > struct S { struct T { char buf[5]; int x; } t; char buf[20]; } var; > With -D_FORTIFY_SOURCE=1, > strcpy (&var.t.buf[1], "abcdefg"); > is not considered an overflow (object is whole VAR), while > with -D_FORTIFY_SOURCE=2 > strcpy (&var.t.buf[1], "abcdefg"); > will be considered a buffer overflow. > =============================================== > > This example is very close to what vim does. So it makes sense > that -D_FORTIFY_SOURCE=2 detects an overflow, while > -D_FORTIFY_SOURCE=1 does not. > > Adding -D_FORTIFY_SOURCE=1 to Vim makefile sounds like > a good idea. This makes sense. It actually mentions that -D_FORTIFY_SOURCE=2 may break confirming programs. This also means it should never be the default. So perhaps you can file a bug that the default should be to use 1. The argument is only needed for GCC 4 and later, right? That's why I didn't notice this, I'm using gcc 3.4.6 (FreeBSD is very conservative about gcc versions, for a good reason). So we can add a configure check. The patch below should work, if the information is correct. *** ../vim-7.2.042/src/auto/configure Thu Jul 24 17:20:50 2008 --- src/auto/configure Sun Nov 16 17:08:44 2008 *************** *** 16819,16839 **** LDFLAGS="$LDFLAGS -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch ppc" fi - { $as_echo "$as_me:$LINENO: checking for GCC 3 or later" >&5 - $as_echo_n "checking for GCC 3 or later... " >&6; } DEPEND_CFLAGS_FILTER= if test "$GCC" = yes; then gccmajor=`echo "$gccversion" | sed -e 's/^\([1-9]\)\..*$/\1/g'` if test "$gccmajor" -gt "2"; then DEPEND_CFLAGS_FILTER="| sed 's+-I */+-isystem /+g'" ! fi ! fi ! if test "$DEPEND_CFLAGS_FILTER" = ""; then ! { $as_echo "$as_me:$LINENO: result: no" >&5 $as_echo "no" >&6; } ! else ! { $as_echo "$as_me:$LINENO: result: yes" >&5 $as_echo "yes" >&6; } fi --- 16819,16847 ---- LDFLAGS="$LDFLAGS -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch ppc" fi DEPEND_CFLAGS_FILTER= if test "$GCC" = yes; then + { $as_echo "$as_me:$LINENO: checking for GCC 3 or later" >&5 + $as_echo_n "checking for GCC 3 or later... " >&6; } gccmajor=`echo "$gccversion" | sed -e 's/^\([1-9]\)\..*$/\1/g'` if test "$gccmajor" -gt "2"; then DEPEND_CFLAGS_FILTER="| sed 's+-I */+-isystem /+g'" ! { $as_echo "$as_me:$LINENO: result: yes" >&5 ! $as_echo "yes" >&6; } ! else ! { $as_echo "$as_me:$LINENO: result: no" >&5 $as_echo "no" >&6; } ! fi ! { $as_echo "$as_me:$LINENO: checking whether we need -D_FORTIFY_SOURCE=1" >&5 ! $as_echo_n "checking whether we need -D_FORTIFY_SOURCE=1... " >&6; } ! if test "$gccmajor" -gt "3"; then ! CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=1" ! { $as_echo "$as_me:$LINENO: result: yes" >&5 $as_echo "yes" >&6; } + else + { $as_echo "$as_me:$LINENO: result: no" >&5 + $as_echo "no" >&6; } + fi fi *** ../vim-7.2.042/src/configure.in Thu Jul 24 17:20:31 2008 --- src/configure.in Sun Nov 16 17:08:40 2008 *************** *** 3152,3169 **** dnl But only when making dependencies, cproto and lint don't take "-isystem". dnl Mac gcc returns "powerpc-apple-darwin8-gcc-4.0.1 (GCC)...", need to allow dnl the number before the version number. - AC_MSG_CHECKING(for GCC 3 or later) DEPEND_CFLAGS_FILTER= if test "$GCC" = yes; then gccmajor=`echo "$gccversion" | sed -e 's/^\([[1-9]]\)\..*$/\1/g'` if test "$gccmajor" -gt "2"; then DEPEND_CFLAGS_FILTER="| sed 's+-I */+-isystem /+g'" fi - fi - if test "$DEPEND_CFLAGS_FILTER" = ""; then - AC_MSG_RESULT(no) - else - AC_MSG_RESULT(yes) fi AC_SUBST(DEPEND_CFLAGS_FILTER) --- 3152,3176 ---- dnl But only when making dependencies, cproto and lint don't take "-isystem". dnl Mac gcc returns "powerpc-apple-darwin8-gcc-4.0.1 (GCC)...", need to allow dnl the number before the version number. DEPEND_CFLAGS_FILTER= if test "$GCC" = yes; then + AC_MSG_CHECKING(for GCC 3 or later) gccmajor=`echo "$gccversion" | sed -e 's/^\([[1-9]]\)\..*$/\1/g'` if test "$gccmajor" -gt "2"; then DEPEND_CFLAGS_FILTER="| sed 's+-I */+-isystem /+g'" + AC_MSG_RESULT(yes) + else + AC_MSG_RESULT(no) + fi + dnl -D_FORTIFY_SOURCE=2 crashes Vim on strcpy(buf, "000") when buf is + dnl declared as char x[1] but actually longer. Introduced in gcc 4.0. + AC_MSG_CHECKING(whether we need -D_FORTIFY_SOURCE=1) + if test "$gccmajor" -gt "3"; then + CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=1" + AC_MSG_RESULT(yes) + else + AC_MSG_RESULT(no) fi fi AC_SUBST(DEPEND_CFLAGS_FILTER) *** ../vim-7.2.042/src/eval.c Wed Nov 12 15:28:37 2008 --- src/eval.c Sun Nov 16 17:00:17 2008 *************** *** 21150,21157 **** init_var_dict(&fc.l_avars, &fc.l_avars_var); add_nr_var(&fc.l_avars, &fc.fixvar[fixvar_idx++].var, "0", (varnumber_T)(argcount - fp->uf_args.ga_len)); v = &fc.fixvar[fixvar_idx++].var; ! STRCPY(v->di_key, "000"); v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX; hash_add(&fc.l_avars.dv_hashtab, DI2HIKEY(v)); v->di_tv.v_type = VAR_LIST; --- 21150,21160 ---- init_var_dict(&fc.l_avars, &fc.l_avars_var); add_nr_var(&fc.l_avars, &fc.fixvar[fixvar_idx++].var, "0", (varnumber_T)(argcount - fp->uf_args.ga_len)); + /* Use "name" to avoid a warning from some compiler that checks the + * destination size. */ v = &fc.fixvar[fixvar_idx++].var; ! name = v->di_key; ! STRCPY(name, "000"); v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX; hash_add(&fc.l_avars.dv_hashtab, DI2HIKEY(v)); v->di_tv.v_type = VAR_LIST; *************** *** 21394,21400 **** char *name; varnumber_T nr; { ! STRCPY(v->di_key, name); v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX; hash_add(&dp->dv_hashtab, DI2HIKEY(v)); v->di_tv.v_type = VAR_NUMBER; --- 21397,21408 ---- char *name; varnumber_T nr; { ! char_u *kname; ! ! /* Use an intermediate variable to avoid a warning when the compiler does ! * function inlining. */ ! kname = v->di_key; ! STRCPY(kname, name); v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX; hash_add(&dp->dv_hashtab, DI2HIKEY(v)); v->di_tv.v_type = VAR_NUMBER; -- hundred-and-one symptoms of being an internet addict: 268. You get up in the morning and go online before getting your coffee. /// Bram Moolenaar -- [EMAIL PROTECTED] -- http://www.Moolenaar.net \\\ /// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\ \\\ download, build and distribute -- http://www.A-A-P.org /// \\\ help me help AIDS victims -- http://ICCF-Holland.org /// --~--~---------~--~----~------------~-------~--~----~ You received this message from the "vim_dev" maillist. For more information, visit http://www.vim.org/maillist.php -~----------~----~----~----~------~----~------~--~---
