From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Stoppa Subject: [PATCH 05/12] __wr_after_init: x86_64: debug writes Date: Wed, 19 Dec 2018 23:33:31 +0200 Message-Id: <20181219213338.26619-6-igor.stoppa@huawei.com> In-Reply-To: <20181219213338.26619-1-igor.stoppa@huawei.com> References: <20181219213338.26619-1-igor.stoppa@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: Andy Lutomirski , Matthew Wilcox , Peter Zijlstra , Dave Hansen , Mimi Zohar Cc: igor.stoppa@huawei.com, Nadav Amit , Kees Cook , linux-integrity@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: After each write operation, confirm that it was successful, otherwise generate a warning. Signed-off-by: Igor Stoppa CC: Andy Lutomirski CC: Nadav Amit CC: Matthew Wilcox CC: Peter Zijlstra CC: Kees Cook CC: Dave Hansen CC: Mimi Zohar CC: linux-integrity@vger.kernel.org CC: kernel-hardening@lists.openwall.com CC: linux-mm@kvack.org CC: linux-kernel@vger.kernel.org --- arch/x86/mm/prmem.c | 9 ++++++++- mm/Kconfig.debug | 8 ++++++++ 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/prmem.c b/arch/x86/mm/prmem.c index fc367551e736..9d98525c687a 100644 --- a/arch/x86/mm/prmem.c +++ b/arch/x86/mm/prmem.c @@ -60,7 +60,14 @@ void *__wr_op(unsigned long dst, unsigned long src, __kernel_size_t len, copy_to_user((void __user *)wr_poking_addr, (void *)src, len); else if (op == WR_MEMSET) memset_user((void __user *)wr_poking_addr, (u8)src, len); - +#ifdef CONFIG_DEBUG_PRMEM + if (op == WR_MEMCPY) + VM_WARN_ONCE(memcmp((void *)dst, (void *)src, len), + "Failed wr_memcpy()"); + else if (op == WR_MEMSET) + VM_WARN_ONCE(memtst((void *)dst, (u8)src, len), + "Failed wr_memset()"); +#endif unuse_temporary_mm(prev); local_irq_enable(); return (void *)dst; diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 9a7b8b049d04..b10305cfac3c 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -94,3 +94,11 @@ config DEBUG_RODATA_TEST depends on STRICT_KERNEL_RWX ---help--- This option enables a testcase for the setting rodata read-only. + +config DEBUG_PRMEM + bool "Verify each write rare operation." + depends on PRMEM + default n + help + After any write rare operation, compares the data written with the + value provided by the caller. -- 2.19.1