From 949e63eed618a19098fa7258654854a9040d3b49 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 14 Feb 2019 20:48:24 +0800 Subject: [PATCH] lib/vsprintf: Hash printed address for netdev bits fallback mainline inclusion from mainline-4.20 commit 431bca24308c category: bugfix bugzilla: 5743 CVE: NA ------------------------------------------------- The handler for "%pN" falls back to printing the raw pointer value when using a different format than the (sole supported) special format "%pNF", potentially leaking sensitive information regarding the kernel layout in memory. Avoid this leak by printing the hashed address instead. Note that there are no in-tree users of the fallback. Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p") Link: http://lkml.kernel.org/r/20181011084249.4520-4-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 Signed-off-by: Cheng Jian Reviewed-by: Xie XiuQi Signed-off-by: Yang Yingliang --- lib/vsprintf.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 713757556aaa..606b0187f6ff 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1510,7 +1510,8 @@ char *restricted_pointer(char *buf, char *end, const void *ptr, } static noinline_for_stack -char *netdev_bits(char *buf, char *end, const void *addr, const char *fmt) +char *netdev_bits(char *buf, char *end, const void *addr, + struct printf_spec spec, const char *fmt) { unsigned long long num; int size; @@ -1521,9 +1522,7 @@ char *netdev_bits(char *buf, char *end, const void *addr, const char *fmt) size = sizeof(netdev_features_t); break; default: - num = (unsigned long)addr; - size = sizeof(unsigned long); - break; + return ptr_to_id(buf, end, addr, spec); } return special_hex_number(buf, end, num, size); @@ -1945,7 +1944,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, break; return restricted_pointer(buf, end, ptr, spec); case 'N': - return netdev_bits(buf, end, ptr, fmt); + return netdev_bits(buf, end, ptr, spec, fmt); case 'a': return address_val(buf, end, ptr, fmt); case 'd': -- GitLab