Alf mel wrote: > > While trying out the lastest offerings in Glibc (2.6.1) and GCC (4.2.1) via > > the DIY-Linux project (www.diy-linux-.org), I encountered the following > > error in the configure script when compiled with > > > > CFLAGS="-O2 -fstack-protector -D_FORTIFY_SOURCE=2". > > > > Here is what I get: > > > > checking whether printf supports size specifiers as in C99... yes > > checking whether printf supports 'long double' arguments... yes > > checking whether printf supports infinite 'double' arguments... yes > > checking whether printf supports infinite 'long double' arguments... *** > > buffer overflow detected ***: ./conftest terminated > > ======= Backtrace: ========= > > /lib/libc.so.6(__chk_fail+0x41)[0xb7ed4191] > > /lib/libc.so.6[0xb7ed3998] > > /lib/libc.so.6(_IO_default_xsputn+0xb7)[0xb7e53d47] > > /lib/libc.so.6(__printf_fp+0x6a9)[0xb7e30559] > > /lib/libc.so.6(_IO_vfprintf+0x3c7)[0xb7e2b877] > > /lib/libc.so.6(__vsprintf_chk+0xad)[0xb7ed3a4d] > > /lib/libc.so.6(__sprintf_chk+0x30)[0xb7ed3980] > > ./conftest[0x8048d11] > > /lib/libc.so.6(__libc_start_main+0xe0)[0xb7e03f90] > > ./conftest[0x8048311] > > ======= Memory map: ======== > > 08048000-0804a000 r-xp 00000000 08:06 > > 6295768 /var/local/slim/build/m4/source/m4-1.4.10/conftest > > 0804a000-0804b000 rw-p 00001000 08:06 > > 6295768 /var/local/slim/build/m4/source/m4-1.4.10/conftest > > 0804b000-0806c000 rw-p 0804b000 00:00 0 [heap] > > b7de2000-b7dec000 r-xp 00000000 08:01 134 /usr/lib/libgcc_s.so.1 > > b7dec000-b7ded000 rw-p 00009000 08:01 134 /usr/lib/libgcc_s.so.1 > > b7ded000-b7dee000 rw-p b7ded000 00:00 0 > > b7dee000-b7f2d000 r-xp 00000000 08:01 20983511 /lib/libc-2.6.1.so > > b7f2d000-b7f2f000 r--p 0013f000 08:01 20983511 /lib/libc-2.6.1.so > > b7f2f000-b7f30000 rw-p 00141000 08:01 20983511 /lib/libc-2.6.1.so > > b7f30000-b7f34000 rw-p b7f30000 00:00 0 > > b7f37000-b7f53000 r-xp 00000000 08:01 20983504 /lib/ld-2.6.1.so > > b7f53000-b7f54000 r--p 0001b000 08:01 20983504 /lib/ld-2.6.1.so > > b7f54000-b7f55000 rw-p 0001c000 08:01 20983504 /lib/ld-2.6.1.so > > bfad6000-bfaec000 rw-p bfad6000 00:00 0 [stack] > > ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso] > > no
This configure test and how glibc should handle printing of random bitpatterns was subject of a bug report http://sourceware.org/bugzilla/show_bug.cgi?id=4586 and a lengthy discussion. The bug was fixed by Jakub Jelinek in July 2007; the fix should be contained in glibc-2.6.1. Summarizing the discussion: While Ulrich Drepper and Andreas Schwab denied that glibc was doing anything wrong, others thought that glibc should not crash on random bitpatterns passed as floating-point numbers. It appears that the crash is gone, but either a buffer overflow is still present, or some source code annotations for bounds checking needs to be added to __printf_fp and related functions. Can you first reduce the failed configure program (copy & paste from config.log) to a test case as small as possible, and then report it in the glibc bug tracker? > > The buffer overflow doesn't seem to change the result of the test in our > > systems. It is normal that this test says "no" on glibc systems: The gnulib test expects some particular output for invalid numbers; glibc only guarantees not to crash, and returns output that does not make much sense. Bruno _______________________________________________ Bug-m4 mailing list Bug-m4@gnu.org http://lists.gnu.org/mailman/listinfo/bug-m4
