diff mbox series

[08/20] tools lib api fs: Fix gcc9 stringop-truncation compilation error

Message ID 20200106160705.10899-9-acme@kernel.org
State Not Applicable
Delegated to: BPF Maintainers
Headers show
Series None | expand

Commit Message

Arnaldo Carvalho de Melo Jan. 6, 2020, 4:06 p.m. UTC 
From: Andrey Zhizhikin <andrey.z@gmail.com>

GCC9 introduced string hardening mechanisms, which exhibits the error
during fs api compilation:

error: '__builtin_strncpy' specified bound 4096 equals destination size
[-Werror=stringop-truncation]

This comes when the length of copy passed to strncpy is is equal to
destination size, which could potentially lead to buffer overflow.

There is a need to mitigate this potential issue by limiting the size of
destination by 1 and explicitly terminate the destination with NULL.

Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20191211080109.18765-1-andrey.zhizhikin@leica-geosystems.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/api/fs/fs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Petr Mladek Jan. 7, 2020, 9:16 a.m. UTC | #1 
On Mon 2020-01-06 13:06:53, Arnaldo Carvalho de Melo wrote:
> From: Andrey Zhizhikin <andrey.z@gmail.com>
> 
> GCC9 introduced string hardening mechanisms, which exhibits the error
> during fs api compilation:
> 
> error: '__builtin_strncpy' specified bound 4096 equals destination size
> [-Werror=stringop-truncation]
> 
> This comes when the length of copy passed to strncpy is is equal to
> destination size, which could potentially lead to buffer overflow.
> 
> There is a need to mitigate this potential issue by limiting the size of
> destination by 1 and explicitly terminate the destination with NULL.
> 
> Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Andrii Nakryiko <andriin@fb.com>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
> Cc: Martin KaFai Lau <kafai@fb.com>
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Song Liu <songliubraving@fb.com>
> Cc: Yonghong Song <yhs@fb.com>
> Cc: bpf@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Link: http://lore.kernel.org/lkml/20191211080109.18765-1-andrey.zhizhikin@leica-geosystems.com
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr
diff mbox series

Patch

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 11b3885e833e..027b18f7ed8c 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -210,6 +210,7 @@  static bool fs__env_override(struct fs *fs)
 	size_t name_len = strlen(fs->name);
 	/* name + "_PATH" + '\0' */
 	char upper_name[name_len + 5 + 1];
+
 	memcpy(upper_name, fs->name, name_len);
 	mem_toupper(upper_name, name_len);
 	strcpy(&upper_name[name_len], "_PATH");
@@ -219,7 +220,8 @@  static bool fs__env_override(struct fs *fs)
 		return false;
 
 	fs->found = true;
-	strncpy(fs->path, override_path, sizeof(fs->path));
+	strncpy(fs->path, override_path, sizeof(fs->path) - 1);
+	fs->path[sizeof(fs->path) - 1] = '\0';
 	return true;
 }