From: Jiangfeng Xiao <xiaojiangfeng@huawei.com> To: <npiggin@gmail.com>, <aneesh.kumar@kernel.org>, <naveen.n.rao@linux.ibm.com>, <christophe.leroy@csgroup.eu>, <mpe@ellerman.id.au>, <christophe.leroy@c-s.fr>, <xiaojiangfeng@huawei.com> Cc: <linuxppc-dev@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>, <nixiaoming@huawei.com>, <wangbing6@huawei.com>, <douzhaolei@huawei.com>, <wangfangpeng1@huawei.com> Subject: [PING PATCH] powerpc/kasan: Fix addr error caused by page alignment Date: Tue, 23 Jan 2024 09:45:59 +0800 [thread overview] Message-ID: <1705974359-43790-1-git-send-email-xiaojiangfeng@huawei.com> (raw) 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> --- 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: Jiangfeng Xiao <xiaojiangfeng@huawei.com> To: <npiggin@gmail.com>, <aneesh.kumar@kernel.org>, <naveen.n.rao@linux.ibm.com>, <christophe.leroy@csgroup.eu>, <mpe@ellerman.id.au>, <christophe.leroy@c-s.fr>, <xiaojiangfeng@huawei.com> Cc: douzhaolei@huawei.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, wangbing6@huawei.com, wangfangpeng1@huawei.com, nixiaoming@huawei.com Subject: [PING PATCH] powerpc/kasan: Fix addr error caused by page alignment Date: Tue, 23 Jan 2024 09:45:59 +0800 [thread overview] Message-ID: <1705974359-43790-1-git-send-email-xiaojiangfeng@huawei.com> (raw) 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> --- 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 reply other threads:[~2024-01-23 2:07 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-01-23 1:45 Jiangfeng Xiao [this message] 2024-01-23 1:45 ` [PING PATCH] powerpc/kasan: Fix addr error caused by page alignment Jiangfeng Xiao 2024-01-23 7:10 ` Christophe Leroy 2024-01-23 7:10 ` Christophe Leroy 2024-02-15 12:57 ` Michael Ellerman 2024-02-15 12:57 ` Michael Ellerman
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1705974359-43790-1-git-send-email-xiaojiangfeng@huawei.com \ --to=xiaojiangfeng@huawei.com \ --cc=aneesh.kumar@kernel.org \ --cc=christophe.leroy@c-s.fr \ --cc=christophe.leroy@csgroup.eu \ --cc=douzhaolei@huawei.com \ --cc=linux-kernel@vger.kernel.org \ --cc=linuxppc-dev@lists.ozlabs.org \ --cc=mpe@ellerman.id.au \ --cc=naveen.n.rao@linux.ibm.com \ --cc=nixiaoming@huawei.com \ --cc=npiggin@gmail.com \ --cc=wangbing6@huawei.com \ --cc=wangfangpeng1@huawei.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.