From ec12bc2909f9759747ab5ad3709472353c43a750 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 11 Oct 2018 10:42:48 +0200 Subject: 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: ad67b74d2469d9b8 ("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 25dc591cb110..d39798c25585 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 94940ba3a3bc..fee87b038ead 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 } } -- cgit v1.2.3