Re: [PATCH] debug: Add regression tests for BZ 30932

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

On 2023-10-03 14:13, Adhemerval Zanella wrote:
> Checked on x86_64-linux-gnu.
> ---

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

>   debug/Makefile                     |  5 ++
>   debug/tst-sprintf-fortify-rdonly.c | 82 ++++++++++++++++++++++++++++++
>   2 files changed, 87 insertions(+)
>   create mode 100644 debug/tst-sprintf-fortify-rdonly.c
> 
> diff --git a/debug/Makefile b/debug/Makefile
> index 434e52f780..d7e021a1c8 100644
> --- a/debug/Makefile
> +++ b/debug/Makefile
> @@ -178,6 +178,7 @@ CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
>   CPPFLAGS-tst-longjmp_chk3.c += $(no-fortify-source),-D_FORTIFY_SOURCE=1
>   CPPFLAGS-tst-realpath-chk.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
>   CPPFLAGS-tst-chk-cancel.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
> +CFLAGS-tst-sprintf-fortify-rdonly.c += $(no-fortify-source),-D_FORTIFY_SOURCE=2
>   
>   # _FORTIFY_SOURCE tests.
>   # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
> @@ -284,6 +285,7 @@ tests = \
>     tst-longjmp_chk \
>     tst-longjmp_chk2 \
>     tst-realpath-chk \
> +  tst-sprintf-fortify-rdonly \
>     tst-sprintf-fortify-unchecked \
>     # tests
>   
> @@ -291,6 +293,9 @@ tests-time64 += \
>     $(tests-all-time64-chk) \
>     # tests-time64
>   
> +tests-container += \
> +  # tests-container
> +
>   ifeq ($(have-ssp),yes)
>   tests += tst-ssp-1
>   endif
> diff --git a/debug/tst-sprintf-fortify-rdonly.c b/debug/tst-sprintf-fortify-rdonly.c
> new file mode 100644
> index 0000000000..7d5c447598
> --- /dev/null
> +++ b/debug/tst-sprintf-fortify-rdonly.c
> @@ -0,0 +1,82 @@
> +/* Testcase for BZ 30932.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <errno.h>
> +#include <setjmp.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <sys/resource.h>
> +#include <unistd.h>
> +
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/temp_file.h>
> +
> +jmp_buf chk_fail_buf;
> +bool chk_fail_ok;
> +
> +const char *str2 = "F";
> +char buf2[10] = "%s";
> +
> +static int
> +do_test (void)
> +{
> +  struct rlimit rl;
> +  int max_fd = 24;
> +
> +  if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
> +    FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
> +
> +  max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
> +  rl.rlim_cur = max_fd;
> +
> +  if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
> +    FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
> +
> +  /* Exhaust the file descriptor limit with temporary files.  */
> +  int nfiles = 0;
> +  for (; nfiles < max_fd; nfiles++)
> +    {
> +      int fd = create_temp_file ("tst-spawn3.", NULL);
> +      if (fd == -1)
> +	{
> +	  if (errno != EMFILE)
> +	    FAIL_EXIT1 ("create_temp_file: %m");
> +	  break;
> +	}
> +    }
> +  TEST_VERIFY_EXIT (nfiles != 0);
> +
> +  /* When the format string is writable and contains %n,
> +     with -D_FORTIFY_SOURCE=2 it causes __chk_fail.  However, if libc can not
> +     open procfs to check if the input format string in within a writable
> +     memory segment, the fortify version can not perform the check.  */
> +  char buf[128];
> +  int n1;
> +  int n2;
> +
> +  strcpy (buf2 + 2, "%n%s%n");
> +  if (sprintf (buf, buf2, str2, &n1, str2, &n2) != 2
> +      || n1 != 1 || n2 != 2)
> +    FAIL_EXIT1 ("sprintf failed: %s %d %d", buf, n1, n2);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>