2021-05-07 22:14:32

by Arnd Bergmann

Subject: [RFC 09/12] apparmor: use get_unaligned() only for multi-byte words

From: Arnd Bergmann <[email protected]>

Using get_unaligned() on a u8 pointer is pointless, and will
result in a compiler warning after a planned cleanup:

In file included from arch/x86/include/generated/asm/unaligned.h:1,
from security/apparmor/policy_unpack.c:16:
security/apparmor/policy_unpack.c: In function 'unpack_u8':
include/asm-generic/unaligned.h:13:15: error: 'packed' attribute ignored for field of type 'u8' {aka 'unsigned char'} [-Werror=attributes]
13 | const struct { type x __packed; } *__pptr = (typeof(__pptr))(ptr); \
| ^

Simply dereference this pointer directly.

Signed-off-by: Arnd Bergmann <[email protected]>
---
security/apparmor/policy_unpack.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
index b8efbda545cb..0acca6f2a93f 100644
--- a/security/apparmor/policy_unpack.c
+++ b/security/apparmor/policy_unpack.c
@@ -304,7 +304,7 @@ static bool unpack_u8(struct aa_ext *e, u8 *data, const char *name)
if (!inbounds(e, sizeof(u8)))
goto fail;
if (data)
- *data = get_unaligned((u8 *)e->pos);
+ *data = *((u8 *)e->pos);
e->pos += sizeof(u8);
return true;
}
--
2.29.2

2021-05-10 08:19:29

by John Johansen

Subject: Re: [RFC 09/12] apparmor: use get_unaligned() only for multi-byte words

On 5/7/21 3:07 PM, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> Using get_unaligned() on a u8 pointer is pointless, and will
> result in a compiler warning after a planned cleanup:
>
> In file included from arch/x86/include/generated/asm/unaligned.h:1,
> from security/apparmor/policy_unpack.c:16:
> security/apparmor/policy_unpack.c: In function 'unpack_u8':
> include/asm-generic/unaligned.h:13:15: error: 'packed' attribute ignored for field of type 'u8' {aka 'unsigned char'} [-Werror=attributes]
> 13 | const struct { type x __packed; } *__pptr = (typeof(__pptr))(ptr); \
> | ^
>
> Simply dereference this pointer directly.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
Acked-by: John Johansen <[email protected]>

> ---
> security/apparmor/policy_unpack.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
> index b8efbda545cb..0acca6f2a93f 100644
> --- a/security/apparmor/policy_unpack.c
> +++ b/security/apparmor/policy_unpack.c
> @@ -304,7 +304,7 @@ static bool unpack_u8(struct aa_ext *e, u8 *data, const char *name)
> if (!inbounds(e, sizeof(u8)))
> goto fail;
> if (data)
> - *data = get_unaligned((u8 *)e->pos);
> + *data = *((u8 *)e->pos);
> e->pos += sizeof(u8);
> return true;
> }
>