2019-09-18 09:37:19

by Christian Brauner

Subject: [PATCH 3/4] seccomp: avoid overflow in implicit constant conversion

USER_NOTIF_MAGIC is assigned to int variables in this test so set it to INT_MAX
to avoid warnings:

seccomp_bpf.c: In function ‘user_notification_continue’:
seccomp_bpf.c:3088:26: warning: overflow in implicit constant conversion [-Woverflow]
#define USER_NOTIF_MAGIC 116983961184613L
^
seccomp_bpf.c:3572:15: note: in expansion of macro ‘USER_NOTIF_MAGIC’
resp.error = USER_NOTIF_MAGIC;
^~~~~~~~~~~~~~~~

Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace")
Signed-off-by: Christian Brauner <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Will Drewry <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: Tycho Andersen <[email protected]>
CC: Tyler Hicks <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index ee52eab01800..921f0e26f835 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -35,6 +35,7 @@
#include <stdbool.h>
#include <string.h>
#include <time.h>
+#include <limits.h>
#include <linux/elf.h>
#include <sys/uio.h>
#include <sys/utsname.h>
@@ -3080,7 +3081,7 @@ static int user_trap_syscall(int nr, unsigned int flags)
return seccomp(SECCOMP_SET_MODE_FILTER, flags, &prog);
}

-#define USER_NOTIF_MAGIC 116983961184613L
+#define USER_NOTIF_MAGIC INT_MAX
TEST(user_notification_basic)
{
pid_t pid;
--
2.23.0

2019-09-18 13:01:53

by Tyler Hicks

Subject: Re: [PATCH 3/4] seccomp: avoid overflow in implicit constant conversion

On 2019-09-18 10:48:32, Christian Brauner wrote:
> USER_NOTIF_MAGIC is assigned to int variables in this test so set it to INT_MAX
> to avoid warnings:
>
> seccomp_bpf.c: In function ‘user_notification_continue’:
> seccomp_bpf.c:3088:26: warning: overflow in implicit constant conversion [-Woverflow]
> #define USER_NOTIF_MAGIC 116983961184613L
> ^
> seccomp_bpf.c:3572:15: note: in expansion of macro ‘USER_NOTIF_MAGIC’
> resp.error = USER_NOTIF_MAGIC;
> ^~~~~~~~~~~~~~~~
>
> Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace")
> Signed-off-by: Christian Brauner <[email protected]>
> Cc: Kees Cook <[email protected]>
> Cc: Andy Lutomirski <[email protected]>
> Cc: Will Drewry <[email protected]>
> Cc: Shuah Khan <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
> Cc: Daniel Borkmann <[email protected]>
> Cc: Martin KaFai Lau <[email protected]>
> Cc: Song Liu <[email protected]>
> Cc: Yonghong Song <[email protected]>
> Cc: Tycho Andersen <[email protected]>
> CC: Tyler Hicks <[email protected]>

INT_MAX should be a safe value to use.

Reviewed-by: Tyler Hicks <[email protected]>

Tyler

> Cc: Jann Horn <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> ---
> tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
> index ee52eab01800..921f0e26f835 100644
> --- a/tools/testing/selftests/seccomp/seccomp_bpf.c
> +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
> @@ -35,6 +35,7 @@
> #include <stdbool.h>
> #include <string.h>
> #include <time.h>
> +#include <limits.h>
> #include <linux/elf.h>
> #include <sys/uio.h>
> #include <sys/utsname.h>
> @@ -3080,7 +3081,7 @@ static int user_trap_syscall(int nr, unsigned int flags)
> return seccomp(SECCOMP_SET_MODE_FILTER, flags, &prog);
> }
>
> -#define USER_NOTIF_MAGIC 116983961184613L
> +#define USER_NOTIF_MAGIC INT_MAX
> TEST(user_notification_basic)
> {
> pid_t pid;
> --
> 2.23.0
>