From: Dave Hansen <dave.hansen@intel.com>
To: Yuntao Wang <ytcoode@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Baoquan He <bhe@redhat.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
x86@kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] x86/mm: Fix possible index overflow when creating page table mapping
Date: Thu, 16 Jun 2022 07:02:56 -0700 [thread overview]
Message-ID: <3e754cf7-35f8-0163-a24a-063fa3d96718@intel.com> (raw)
In-Reply-To: <20220616135510.1784995-1-ytcoode@gmail.com>
On 6/16/22 06:55, Yuntao Wang wrote:
> There are two issues in phys_p4d_init():
>
> - The __kernel_physical_mapping_init() does not do boundary-checking for
> paddr_end and passes it directly to phys_p4d_init(), phys_p4d_init() does
> not do bounds checking either, so if the physical memory to be mapped is
> large enough, 'p4d_page + p4d_index(vaddr)' will wrap around to the
> beginning entry of the P4D table and its data will be overwritten.
>
> - The for loop body will be executed only when 'vaddr < vaddr_end'
> evaluates to true, but if that condition is true, 'paddr >= paddr_end'
> will evaluate to false, thus the 'if (paddr >= paddr_end) {}' block will
> never be executed and become dead code.
Could you explain a bit how you found this? Was this encountered in
practice and debugged or was it found by inspection?
next prev parent reply other threads:[~2022-06-16 14:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 13:55 Yuntao Wang
2022-06-16 14:02 ` Dave Hansen [this message]
2022-06-16 14:15 ` Yuntao Wang
2022-06-16 14:20 ` Dave Hansen
2022-06-17 6:38 ` Yuntao Wang
2022-06-18 0:22 ` Kirill A. Shutemov
2022-06-18 2:08 ` Yuntao Wang
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