From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
Russell King <rmk+kernel@armlinux.org.uk>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 4.14 8/9] ARM: ensure the signal page contains defined contents
Date: Mon, 8 Feb 2021 12:59:45 -0500 [thread overview]
Message-ID: <20210208175946.2092374-8-sashal@kernel.org> (raw)
In-Reply-To: <20210208175946.2092374-1-sashal@kernel.org>
From: Russell King <rmk+kernel@armlinux.org.uk>
[ Upstream commit 9c698bff66ab4914bb3d71da7dc6112519bde23e ]
Ensure that the signal page contains our poison instruction to increase
the protection against ROP attacks and also contains well defined
contents.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/kernel/signal.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 02e6b6dfffa7e..19e4ff507209b 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -667,18 +667,20 @@ struct page *get_signal_page(void)
addr = page_address(page);
+ /* Poison the entire page */
+ memset32(addr, __opcode_to_mem_arm(0xe7fddef1),
+ PAGE_SIZE / sizeof(u32));
+
/* Give the signal return code some randomness */
offset = 0x200 + (get_random_int() & 0x7fc);
signal_return_offset = offset;
- /*
- * Copy signal return handlers into the vector page, and
- * set sigreturn to be a pointer to these.
- */
+ /* Copy signal return handlers into the page */
memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
- ptr = (unsigned long)addr + offset;
- flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));
+ /* Flush out all instructions in this page */
+ ptr = (unsigned long)addr;
+ flush_icache_range(ptr, ptr + PAGE_SIZE);
return page;
}
--
2.27.0
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prev parent reply other threads:[~2021-02-08 18:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 17:59 [PATCH AUTOSEL 4.14 1/9] arm64: dts: rockchip: Fix PCIe DT properties on rk3399 Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.14 7/9] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL Sasha Levin
2021-02-08 17:59 ` Sasha Levin [this message]
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