From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Petr Mladek <pmladek@suse.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"Tobin C . Harding" <me@tobin.cc>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH v2 3/3] lib/vsprintf: Hash printed address for netdev bits fallback
Date: Thu, 11 Oct 2018 10:42:49 +0200 [thread overview]
Message-ID: <20181011084249.4520-4-geert+renesas@glider.be> (raw)
In-Reply-To: <20181011084249.4520-1-geert+renesas@glider.be>
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")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Petr Mladek <pmladek@suse.com>
---
v2:
- Add Reviewed-by.
---
lib/vsprintf.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3ea2119b85ac2e4f..4c75d847c1453ca4 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);
@@ -1949,7 +1948,7 @@ 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':
--
2.17.1
next prev parent reply other threads:[~2018-10-11 8:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 8:42 [PATCH v2 0/3] lib/vsprintf: Hash remaining raw addresses Geert Uytterhoeven
2018-10-11 8:42 ` [PATCH v2 1/3] lib/vsprintf: Prepare for more general use of ptr_to_id() Geert Uytterhoeven
2018-10-12 10:39 ` Petr Mladek
2018-10-12 11:25 ` Geert Uytterhoeven
2018-10-11 8:42 ` [PATCH v2 2/3] lib/vsprintf: Hash legacy clock addresses Geert Uytterhoeven
2018-10-12 10:39 ` Petr Mladek
2018-10-11 8:42 ` Geert Uytterhoeven [this message]
2018-10-12 10:40 ` [PATCH v2 3/3] lib/vsprintf: Hash printed address for netdev bits fallback Petr Mladek
2018-10-11 17:01 ` [PATCH v2 0/3] lib/vsprintf: Hash remaining raw addresses Andy Shevchenko
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