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From: Dave Hansen <dave.hansen@intel.com>
To: jeffxu@chromium.org, luto@kernel.org, jorgelo@chromium.org,
	keescook@chromium.org, groeck@chromium.org, jannh@google.com,
	sroettger@google.com
Cc: akpm@linux-foundation.org, jeffxu@google.com,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH 1/6] PKEY: Introduce PKEY_ENFORCE_API flag
Date: Tue, 16 May 2023 16:14:47 -0700	[thread overview]
Message-ID: <6cb7df56-0479-30be-5389-b4b819572deb@intel.com> (raw)
In-Reply-To: <20230515130553.2311248-2-jeffxu@chromium.org>

On 5/15/23 06:05, jeffxu@chromium.org wrote:
> --- a/arch/x86/mm/pkeys.c
> +++ b/arch/x86/mm/pkeys.c
> @@ -20,7 +20,7 @@ int __execute_only_pkey(struct mm_struct *mm)
>  	/* Do we need to assign a pkey for mm's execute-only maps? */
>  	if (execute_only_pkey == -1) {
>  		/* Go allocate one to use, which might fail */
> -		execute_only_pkey = mm_pkey_alloc(mm);
> +		execute_only_pkey = mm_pkey_alloc(mm, 0);
>  		if (execute_only_pkey < 0)
>  			return -1;
>  		need_to_set_mm_pkey = true;

In your threat model, what mechanism prevents the attacker from
modifying executable mappings?

I was trying to figure out if the implicit execute-only pkey should have
the PKEY_ENFORCE_API bit set.  I think that in particular would probably
cause some kind of ABI breakage, but it still reminded me that I have an
incomplete picture of the threat model.

  reply	other threads:[~2023-05-16 23:14 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-15 13:05 [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1 jeffxu
2023-05-15 13:05 ` [PATCH 1/6] PKEY: Introduce PKEY_ENFORCE_API flag jeffxu
2023-05-16 23:14   ` Dave Hansen [this message]
2023-05-16 23:55     ` Jeff Xu
2023-05-17 11:07     ` Stephen Röttger
2023-05-15 13:05 ` [PATCH 2/6] PKEY: Add arch_check_pkey_enforce_api() jeffxu
2023-05-18 21:43   ` Dave Hansen
2023-05-18 22:51     ` Jeff Xu
2023-05-19  0:00       ` Dave Hansen
2023-05-19 11:22         ` Stephen Röttger
2023-05-15 13:05 ` [PATCH 3/6] PKEY: Apply PKEY_ENFORCE_API to mprotect jeffxu
2023-05-16 20:07   ` Kees Cook
2023-05-16 22:23     ` Jeff Xu
2023-05-16 23:18   ` Dave Hansen
2023-05-16 23:36     ` Jeff Xu
2023-05-17  4:50       ` Jeff Xu
2023-05-15 13:05 ` [PATCH 4/6] PKEY:selftest pkey_enforce_api for mprotect jeffxu
2023-05-15 13:05 ` [PATCH 5/6] KEY: Apply PKEY_ENFORCE_API to munmap jeffxu
2023-05-16 20:06   ` Kees Cook
2023-05-16 22:24     ` Jeff Xu
2023-05-16 23:23   ` Dave Hansen
2023-05-17  0:08     ` Jeff Xu
2023-05-15 13:05 ` [PATCH 6/6] PKEY:selftest pkey_enforce_api for munmap jeffxu
2023-05-15 14:28 ` [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1 Dave Hansen
2023-05-16  7:06   ` Stephen Röttger
2023-05-16 22:41     ` Dave Hansen
2023-05-17 10:51       ` Stephen Röttger
2023-05-17 15:07         ` Dave Hansen
2023-05-17 15:21           ` Jeff Xu
2023-05-17 15:29             ` Dave Hansen
2023-05-17 23:48               ` Jeff Xu
2023-05-18 15:37                 ` Dave Hansen
2023-05-18 20:20                   ` Jeff Xu
2023-05-18 21:04                     ` Dave Hansen
2023-05-19 11:13                       ` Stephen Röttger
2023-05-24 20:15                       ` Jeff Xu
2023-06-01  1:39                       ` Jeff Xu
2023-06-01 16:16                         ` Dave Hansen
2023-05-31 23:02                   ` Jeff Xu
2023-05-16 20:08 ` Kees Cook
2023-05-16 22:17   ` Jeff Xu
2023-05-16 22:30     ` Dave Hansen
2023-05-16 23:39       ` Jeff Xu
2023-05-17 10:49   ` Stephen Röttger

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