linux-kernel - Re: [PATCH 0/2] apparmor unaligned memory fixes

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Message-ID: <78f1ff26f06c0e61d71c1a7f05a7c03c4ec03bef.camel@physik.fu-berlin.de>
Date: Wed, 26 Nov 2025 17:16:52 +0100
From: John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>
To: Helge Deller <deller@...nel.org>, John Johansen
	 <john.johansen@...onical.com>, david laight <david.laight@...box.com>
Cc: linux-kernel@...r.kernel.org, apparmor@...ts.ubuntu.com, 
	linux-security-module@...r.kernel.org, linux-parisc@...r.kernel.org
Subject: Re: [PATCH 0/2] apparmor unaligned memory fixes

Hi Helge,

On Wed, 2025-11-26 at 12:31 +0100, Helge Deller wrote:
> Like this (untested!) patch:
> 
> [PATCH] apparmor: Optimize table creation from possibly unaligned memory
> 
> Source blob may come from userspace and might be unaligned.
> Try to optize the copying process by avoiding unaligned memory accesses.
> 
> Signed-off-by: Helge Deller <deller@....de>
> 
> diff --git a/security/apparmor/include/match.h b/security/apparmor/include/match.h
> index 1fbe82f5021b..225df6495c84 100644
> --- a/security/apparmor/include/match.h
> +++ b/security/apparmor/include/match.h
> @@ -111,9 +111,14 @@ struct aa_dfa {
>  		typeof(LEN) __i; \
>  		TTYPE *__t = (TTYPE *) TABLE; \
>  		BTYPE *__b = (BTYPE *) BLOB; \
> -		for (__i = 0; __i < LEN; __i++) { \
> -			__t[__i] = NTOHX(__b[__i]); \
> -		} \
> +		BUILD_BUG_ON(sizeof(TTYPE) != sizeof(BTYPE)); \
> +		/* copy to naturally aligned table address */ \
> +		memcpy(__t, __b, (LEN) * sizeof(BTYPE)); \
> +		/* convert from big-endian if necessary */ \
> +		if (!IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) \
> +			for (__i = 0; __i < LEN; __i++, __t++) { \
> +				*__t = NTOHX(*__t); \
> +			} \
>  	} while (0)
>  
>  static inline size_t table_size(size_t len, size_t el_size)

So, is this patch supposed to replace all the other proposed patches?

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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