From 9cc4ceda12d7c7675a1225efc7515be57898ace3 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 11 Oct 2018 10:42:48 +0200 Subject: [PATCH] lib/vsprintf: Hash legacy clock addresses On platforms using the Common Clock Framework, "%pC" prints the clock's name. On legacy platforms, it prints the unhashed clock's address, potentially leaking sensitive information regarding the kernel layout in memory. Avoid this leak by printing the hashed address instead. To distinguish between clocks, a 32-bit unique identifier is as good as an actual pointer value. Fixes: 7f32ed5e940bb53e ("printk: hash addresses printed with %p") Link: http://lkml.kernel.org/r/20181011084249.4520-3-geert+renesas@glider.be To: "Tobin C . Harding" To: Andrew Morton To: Jonathan Corbet Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Signed-off-by: Petr Mladek --- Documentation/core-api/printk-formats.rst | 5 ++--- lib/vsprintf.c | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 25dc591cb1108..d39798c255850 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -420,9 +420,8 @@ struct clk %pC pll1 %pCn pll1 -For printing struct clk structures. %pC and %pCn print the name -(Common Clock Framework) or address (legacy clock framework) of the -structure. +For printing struct clk structures. %pC and %pCn print the name of the clock +(Common Clock Framework) or a unique 32-bit ID (legacy clock framework). Passed by reference. diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 94940ba3a3bcd..fee87b038eadf 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1563,7 +1563,7 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec, #ifdef CONFIG_COMMON_CLK return string(buf, end, __clk_get_name(clk), spec); #else - return special_hex_number(buf, end, (unsigned long)clk, sizeof(unsigned long)); + return ptr_to_id(buf, end, clk, spec); #endif } } -- 2.39.5