From: Baoquan He <bhe@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, keescook@chromium.org, kirill@shutemov.name,
yamada.masahiro@socionext.com, tglx@linutronix.de, bp@alien8.de,
hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, x86@kernel.org, thgarnie@google.com,
Baoquan He <bhe@redhat.com>
Subject: [PATCH v4 4/6] x86/mm/KASLR: Fix the wrong calculation of memory region initial size
Date: Thu, 14 Mar 2019 17:46:43 +0800 [thread overview]
Message-ID: <20190314094645.4883-5-bhe@redhat.com> (raw)
In-Reply-To: <20190314094645.4883-1-bhe@redhat.com>
In memory region KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate
the initial size of the direct mapping region. This is correct in
the old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
46 bits, and only 4-level mode was supported.
Later, in commit:
b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
__PHYSICAL_MASK_SHIFT was changed to be always 52 bits, no matter it's
5-level or 4-level. This is wrong for 4-level paging. Then when we
adapt physical memory region size based on available memory, it
will overflow if the amount of system RAM and the padding is bigger
than 64 TB.
In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
---
arch/x86/mm/kaslr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index d7ea6b252594..ebf6d1d92385 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -131,7 +131,7 @@ void __init kernel_randomize_memory(void)
if (!kaslr_memory_enabled())
return;
- kaslr_regions[0].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT);
+ kaslr_regions[0].size_tb = 1 << (MAX_PHYSMEM_BITS - TB_SHIFT);
kaslr_regions[1].size_tb = VMALLOC_SIZE_TB;
/*
--
2.17.2
next prev parent reply other threads:[~2019-03-14 9:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-14 9:46 [PATCH v4 0/6] Several patches to fix code bugs, improve documents and clean up Baoquan He
2019-03-14 9:46 ` [PATCH v4 1/6] x86/mm/KASLR: Improve code comments about struct kaslr_memory_region Baoquan He
2019-03-14 9:46 ` [PATCH v4 2/6] x86/mm/KASLR: Open code unnecessary function get_padding Baoquan He
2019-03-14 9:46 ` [PATCH v4 3/6] mm: Add build time sanity check for struct page size Baoquan He
2019-03-14 9:50 ` Baoquan He
2019-03-14 9:57 ` Baoquan He
2019-03-14 9:46 ` Baoquan He [this message]
2019-03-24 20:58 ` [PATCH v4 4/6] x86/mm/KASLR: Fix the wrong calculation of memory region initial size Thomas Gleixner
2019-03-25 3:46 ` Baoquan He
2019-03-14 9:46 ` [PATCH v4 5/6] x86/mm/KASLR: Calculate the actual size of vmemmap region Baoquan He
2019-03-14 9:46 ` [PATCH v4 6/6] x86/mm/KASLR: Do not adapt the size of the direct mapping region for SGI UV system Baoquan He
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=20190314094645.4883-5-bhe@redhat.com \
--to=bhe@redhat.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=keescook@chromium.org \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=thgarnie@google.com \
--cc=x86@kernel.org \
--cc=yamada.masahiro@socionext.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: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).