From bf9688e623262c5fa9f91e4de0e84db45025076f Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Thu, 15 Feb 2024 07:40:56 -0500 Subject: cdefs: Drop access attribute for _FORTIFY_SOURCE=3 (BZ #31383) When passed a pointer to a zero-sized struct, the access attribute without the third argument misleads -Wstringop-overflow diagnostics to think that a function is writing 1 byte into the zero-sized structs. The attribute doesn't add that much value in this context, so drop it completely for _FORTIFY_SOURCE=3. Resolves: BZ #31383 Signed-off-by: Siddhesh Poyarekar Reviewed-by: Adhemerval Zanella --- io/tst-read-zero.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 io/tst-read-zero.c (limited to 'io/tst-read-zero.c') diff --git a/io/tst-read-zero.c b/io/tst-read-zero.c new file mode 100644 index 0000000000..8d1d30a543 --- /dev/null +++ b/io/tst-read-zero.c @@ -0,0 +1,39 @@ +/* read smoke test for 0-sized structures. + 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 + . */ + +/* Zero-sized structures should not result in any overflow warnings or + errors when fortification is enabled. */ +#include +#include +#include +#include + +int +do_test (void) +{ + struct test_st {} test_info[16]; + int fd = open ("/dev/zero", O_RDONLY, 0); + + if (fd == -1) + FAIL_UNSUPPORTED ("Unable to open /dev/zero: %m"); + + TEST_VERIFY_EXIT (read (fd, test_info, sizeof(test_info)) == 0); + return 0; +} + +#include -- cgit 1.4.1