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Message-Id: <1506816410-10230-6-git-send-email-me@tobin.cc>
Date: Sun, 1 Oct 2017 11:06:49 +1100
From: "Tobin C. Harding" <me@...in.cc>
To: Greg KH <gregkh@...uxfoundation.org>,
Petr Mladek <pmladek@...e.com>,
Joe Perches <joe@...ches.com>,
Ian Campbell <ijc@...lion.org.uk>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Cc: "Tobin C. Harding" <me@...in.cc>,
kernel-hardening@...ts.openwall.com,
linux-kernel@...r.kernel.org,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Steven Rostedt <rostedt@...dmis.org>,
William Roberts <william.c.roberts@...el.com>,
Chris Fries <cfries@...gle.com>,
Dave Weinstein <olorin@...gle.com>
Subject: [RFC V2 5/6] lib: vsprintf: add "%paP", "%papP", and "%padP" specifiers
Add %papP and %padP for address types that need to always be shown
regardless of kptr restrictions. Add %paP is a synonym for %papP, this
is inline with current implementation (%pa is a synonym for %pap).
Signed-off-by: Tobin C. Harding <me@...in.cc>
---
Documentation/printk-formats.txt | 19 +++++++++++++++----
Documentation/sysctl/kernel.txt | 4 ++--
lib/vsprintf.c | 9 +++++++--
3 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 16c9abc..d247bc8 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -119,26 +119,37 @@ For printing struct resources. The ``R`` and ``r`` specifiers result in a
printed resource with (``R``) or without (``r``) a decoded flags member.
Passed by reference.
+Physical addresses types
+========================
+
+::
+
+ %pa[P] 0x01234567 or 0x0123456789abcdef
+
+Synonymous with ``%pap[P]`` (for printing ``phys_addr_t``). See below.
+
Physical addresses types ``phys_addr_t``
========================================
::
- %pa[p] 0x01234567 or 0x0123456789abcdef
+ %pap[P] 0x01234567 or 0x0123456789abcdef
For printing a ``phys_addr_t`` type (and its derivatives, such as
``resource_size_t``) which can vary based on build options, regardless of
-the width of the CPU data path. Passed by reference.
+the width of the CPU data path. Passed by reference. Use the trailing 'P'
+if it needs to be always shown.
DMA addresses types ``dma_addr_t``
==================================
::
- %pad 0x01234567 or 0x0123456789abcdef
+ %pad[P] 0x01234567 or 0x0123456789abcdef
For printing a ``dma_addr_t`` type which can vary based on build options,
-regardless of the width of the CPU data path. Passed by reference.
+regardless of the width of the CPU data path. Passed by reference. Use the
+trailing 'P' if it needs to be always shown.
Raw buffer as an escaped string
===============================
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index b6d45bc..f1d52eb 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -400,8 +400,8 @@ however kernel pointers printed using %pP will continue to be printed.
When kptr_restrict is set to (4), kernel pointers printed with
%p, %pK, %pa, and %p[rR] will be replaced with 0's regardless of
-privileges. Kernel pointers printed using %pP will continue to be
-printed.
+privileges. Kernel pointers printed using %pP, %paP, %papP, %padP will
+continue to be printed.
==============================================================
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index e009325..1a35a7f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1395,21 +1395,26 @@ static noinline_for_stack
char *address_val(char *buf, char *end, const void *addr, const char *fmt)
{
unsigned long long num;
+ int cleanse = kptr_restrict_cleanse_addresses();
+ int decleanse_idx = 1;
int size;
switch (fmt[1]) {
case 'd':
num = *(const dma_addr_t *)addr;
size = sizeof(dma_addr_t);
+ decleanse_idx = 2;
break;
case 'p':
+ decleanse_idx = 2;
+ /* fall through */
default:
num = *(const phys_addr_t *)addr;
size = sizeof(phys_addr_t);
break;
}
-
- if (kptr_restrict_cleanse_addresses())
+ /* 'P' on the tail means don't restrict the pointer. */
+ if (cleanse && (fmt[decleanse_idx] != 'P'))
num = 0UL;
return special_hex_number(buf, end, num, size);
--
2.7.4
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