From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Jiangfeng Xiao <xiaojiangfeng@huawei.com>,
"npiggin@gmail.com" <npiggin@gmail.com>,
"aneesh.kumar@kernel.org" <aneesh.kumar@kernel.org>,
"naveen.n.rao@linux.ibm.com" <naveen.n.rao@linux.ibm.com>,
"mpe@ellerman.id.au" <mpe@ellerman.id.au>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"nixiaoming@huawei.com" <nixiaoming@huawei.com>,
"wangbing6@huawei.com" <wangbing6@huawei.com>,
"douzhaolei@huawei.com" <douzhaolei@huawei.com>,
"wangfangpeng1@huawei.com" <wangfangpeng1@huawei.com>
Subject: Re: [PING PATCH] powerpc/kasan: Fix addr error caused by page alignment
Date: Tue, 23 Jan 2024 07:10:10 +0000 [thread overview]
Message-ID: <dfc07bfb-4fcc-4aa8-bfe6-3987b6741b82@csgroup.eu> (raw)
In-Reply-To: <1705974359-43790-1-git-send-email-xiaojiangfeng@huawei.com>
Le 23/01/2024 à 02:45, Jiangfeng Xiao a écrit :
> [Vous ne recevez pas souvent de courriers de xiaojiangfeng@huawei.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
>
> In kasan_init_region, when k_start is not page aligned,
> at the begin of for loop, k_cur = k_start & PAGE_MASK
> is less than k_start, and then va = block + k_cur - k_start
> is less than block, the addr va is invalid, because the
> memory address space from va to block is not alloced by
> memblock_alloc, which will not be reserved
> by memblock_reserve later, it will be used by other places.
>
> As a result, memory overwriting occurs.
>
> for example:
> int __init __weak kasan_init_region(void *start, size_t size)
> {
> [...]
> /* if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) */
> block = memblock_alloc(k_end - k_start, PAGE_SIZE);
> [...]
> for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
> /* at the begin of for loop
> * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400)
> * va(dcd96c00) is less than block(dcd97000), va is invalid
> */
> void *va = block + k_cur - k_start;
> [...]
> }
> [...]
> }
>
> Therefore, page alignment is performed on k_start before
> memblock_alloc to ensure the validity of the VA address.
>
> Fixes: 663c0c9496a6 ("powerpc/kasan: Fix shadow area set up for modules.")
>
> Signed-off-by: Jiangfeng Xiao <xiaojiangfeng@huawei.com>
Be patient, your patch is not lost. Now we have it twice, see:
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?submitter=76392
> ---
> arch/powerpc/mm/kasan/init_32.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.c
> index a70828a..aa9aa11 100644
> --- a/arch/powerpc/mm/kasan/init_32.c
> +++ b/arch/powerpc/mm/kasan/init_32.c
> @@ -64,6 +64,7 @@ int __init __weak kasan_init_region(void *start, size_t size)
> if (ret)
> return ret;
>
> + k_start = k_start & PAGE_MASK;
> block = memblock_alloc(k_end - k_start, PAGE_SIZE);
> if (!block)
> return -ENOMEM;
> --
> 1.8.5.6
>
WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Jiangfeng Xiao <xiaojiangfeng@huawei.com>,
"npiggin@gmail.com" <npiggin@gmail.com>,
"aneesh.kumar@kernel.org" <aneesh.kumar@kernel.org>,
"naveen.n.rao@linux.ibm.com" <naveen.n.rao@linux.ibm.com>,
"mpe@ellerman.id.au" <mpe@ellerman.id.au>
Cc: "douzhaolei@huawei.com" <douzhaolei@huawei.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"wangbing6@huawei.com" <wangbing6@huawei.com>,
"wangfangpeng1@huawei.com" <wangfangpeng1@huawei.com>,
"nixiaoming@huawei.com" <nixiaoming@huawei.com>
Subject: Re: [PING PATCH] powerpc/kasan: Fix addr error caused by page alignment
Date: Tue, 23 Jan 2024 07:10:10 +0000 [thread overview]
Message-ID: <dfc07bfb-4fcc-4aa8-bfe6-3987b6741b82@csgroup.eu> (raw)
In-Reply-To: <1705974359-43790-1-git-send-email-xiaojiangfeng@huawei.com>
Le 23/01/2024 à 02:45, Jiangfeng Xiao a écrit :
> [Vous ne recevez pas souvent de courriers de xiaojiangfeng@huawei.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
>
> In kasan_init_region, when k_start is not page aligned,
> at the begin of for loop, k_cur = k_start & PAGE_MASK
> is less than k_start, and then va = block + k_cur - k_start
> is less than block, the addr va is invalid, because the
> memory address space from va to block is not alloced by
> memblock_alloc, which will not be reserved
> by memblock_reserve later, it will be used by other places.
>
> As a result, memory overwriting occurs.
>
> for example:
> int __init __weak kasan_init_region(void *start, size_t size)
> {
> [...]
> /* if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) */
> block = memblock_alloc(k_end - k_start, PAGE_SIZE);
> [...]
> for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
> /* at the begin of for loop
> * block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400)
> * va(dcd96c00) is less than block(dcd97000), va is invalid
> */
> void *va = block + k_cur - k_start;
> [...]
> }
> [...]
> }
>
> Therefore, page alignment is performed on k_start before
> memblock_alloc to ensure the validity of the VA address.
>
> Fixes: 663c0c9496a6 ("powerpc/kasan: Fix shadow area set up for modules.")
>
> Signed-off-by: Jiangfeng Xiao <xiaojiangfeng@huawei.com>
Be patient, your patch is not lost. Now we have it twice, see:
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?submitter=76392
> ---
> arch/powerpc/mm/kasan/init_32.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.c
> index a70828a..aa9aa11 100644
> --- a/arch/powerpc/mm/kasan/init_32.c
> +++ b/arch/powerpc/mm/kasan/init_32.c
> @@ -64,6 +64,7 @@ int __init __weak kasan_init_region(void *start, size_t size)
> if (ret)
> return ret;
>
> + k_start = k_start & PAGE_MASK;
> block = memblock_alloc(k_end - k_start, PAGE_SIZE);
> if (!block)
> return -ENOMEM;
> --
> 1.8.5.6
>
next prev parent reply other threads:[~2024-01-23 7:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-23 1:45 [PING PATCH] powerpc/kasan: Fix addr error caused by page alignment Jiangfeng Xiao
2024-01-23 1:45 ` Jiangfeng Xiao
2024-01-23 7:10 ` Christophe Leroy [this message]
2024-01-23 7:10 ` Christophe Leroy
2024-02-15 12:57 ` Michael Ellerman
2024-02-15 12:57 ` Michael Ellerman
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