commit 2bbd07c715275eb6c616988925738a0517180d57

Author: Siddhesh Poyarekar <siddhesh@sourceware.org>

Date:   Fri Dec 17 18:35:44 2021 +0530

    fortify: Fix spurious warning with realpath

    The length and object size arguments were swapped around for realpath.

    Also add a smoke test so that any changes in this area get caught in

    future.

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

    Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

diff --git a/debug/Makefile b/debug/Makefile

index 81361438fc3d2aa9..b43f42ee3851f360 100644

--- a/debug/Makefile

+++ b/debug/Makefile

@@ -108,6 +108,7 @@ CFLAGS-tst-longjmp_chk2.c += -fexceptions -fasynchronous-unwind-tables

 CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1

 CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables

 CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1

+CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2

 # We know these tests have problems with format strings, this is what

 # we are testing.  Disable that warning.  They are also testing

@@ -155,7 +156,7 @@ tests = backtrace-tst tst-longjmp_chk tst-chk1 tst-chk2 tst-chk3 \

 	tst-lfschk1 tst-lfschk2 tst-lfschk3 test-strcpy_chk test-stpcpy_chk \

 	tst-chk4 tst-chk5 tst-chk6 tst-chk7 tst-chk8 tst-lfschk4 tst-lfschk5 \

 	tst-lfschk6 tst-longjmp_chk2 tst-backtrace2 tst-backtrace3 \

-	tst-backtrace4 tst-backtrace5 tst-backtrace6

+	tst-backtrace4 tst-backtrace5 tst-backtrace6 tst-realpath-chk

 ifeq ($(have-ssp),yes)

 tests += tst-ssp-1

diff --git a/debug/tst-realpath-chk.c b/debug/tst-realpath-chk.c

new file mode 100644

index 0000000000000000..a8fcb327c43fb34d

--- /dev/null

+++ b/debug/tst-realpath-chk.c

@@ -0,0 +1,37 @@

+/* Smoke test to verify that realpath does not cause spurious warnings.

+   Copyright The GNU Toolchain Authors.

+   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 <limits.h>

+#include <stdlib.h>

+

+#include <support/check.h>

+#include <support/support.h>

+

+static int

+do_test (void)

+{

+#ifdef PATH_MAX

+  char buf[PATH_MAX + 1];

+  char *res = realpath (".", buf);

+  TEST_VERIFY (res == buf);

+#endif

+

+  return 0;

+}

+

+#include <support/test-driver.c>

diff --git a/stdlib/bits/stdlib.h b/stdlib/bits/stdlib.h

index 7ea364a276497720..81ec9bdb32215e3b 100644

--- a/stdlib/bits/stdlib.h

+++ b/stdlib/bits/stdlib.h

@@ -42,7 +42,7 @@ __NTH (realpath (const char *__restrict __name, char *__restrict __resolved))

     return __realpath_alias (__name, __resolved);

 #if defined _LIBC_LIMITS_H_ && defined PATH_MAX

-  if (__glibc_unsafe_len (sz, sizeof (char), PATH_MAX))

+  if (__glibc_unsafe_len (PATH_MAX, sizeof (char), sz))

     return __realpath_chk_warn (__name, __resolved, sz);

 #endif

   return __realpath_chk (__name, __resolved, sz);