From: Adam Borowski <kilobyte@angband.pl>
To: Petr Mladek <pmladek@suse.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"Tobin C . Harding" <me@tobin.cc>, Joe Perches <joe@perches.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>
Cc: Adam Borowski <kilobyte@angband.pl>
Subject: [PATCH 1/2] vsprintf: distinguish between (null), (err) and (invalid) pointer derefs
Date: Tue, 6 Mar 2018 19:11:21 +0100 [thread overview]
Message-ID: <20180306181122.11449-1-kilobyte@angband.pl> (raw)
In-Reply-To: <20180306092513.ibodfsnv4xrxdlub@pathway.suse.cz>
Attempting to print an object pointed to by a bad (usually ERR_PTR) pointer
is a not so surprising error. Our code handles them inconsistently:
* two places print (null) if ptr<PAGE_SIZE
* one place prints (null) if abs(ptr)<PAGE_SIZE
* one place prints (null) only if !ptr
Obviously, saying (null) for a small but non-0 value is misleading.
Thus, let's print:
* (null) for exactly 0
* (err) if last page && abs(ptr)<=MAX_ERRNO
* (invalid) otherwise
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
---
lib/vsprintf.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index d7a708f82559..1c2c3cc5a321 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -47,6 +47,8 @@
#include <linux/string_helpers.h>
#include "kstrtox.h"
+#define BAD_PTR_STRING(x) (!(x) ? "(null)" : IS_ERR(x) ? "(err)" : "(invalid)")
+
/**
* simple_strtoull - convert a string to an unsigned long long
* @cp: The start of the string
@@ -588,7 +590,7 @@ char *string(char *buf, char *end, const char *s, struct printf_spec spec)
size_t lim = spec.precision;
if ((unsigned long)s < PAGE_SIZE)
- s = "(null)";
+ s = BAD_PTR_STRING(s);
while (lim--) {
char c = *s++;
@@ -1582,7 +1584,7 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
return string(buf, end, "(!OF)", spec);
if ((unsigned long)dn < PAGE_SIZE)
- return string(buf, end, "(null)", spec);
+ return string(buf, end, BAD_PTR_STRING(dn), spec);
/* simple case without anything any more format specifiers */
fmt++;
@@ -1851,12 +1853,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
if (!ptr && *fmt != 'K' && *fmt != 'x') {
/*
- * Print (null) with the same width as a pointer so it makes
- * tabular output look nice.
+ * Print (null)/etc with the same width as a pointer so it
+ * makes tabular output look nice.
*/
if (spec.field_width == -1)
spec.field_width = default_width;
- return string(buf, end, "(null)", spec);
+ return string(buf, end, BAD_PTR_STRING(ptr), spec);
}
switch (*fmt) {
@@ -2575,7 +2577,7 @@ int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
|| (unsigned long)save_str < PAGE_SIZE)
- save_str = "(null)";
+ save_str = BAD_PTR_STRING(save_str);
len = strlen(save_str) + 1;
if (str + len < end)
memcpy(str, save_str, len);
--
2.16.2
next prev parent reply other threads:[~2018-03-06 18:12 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-16 21:07 [PATCH v2 1/9] lib/test_printf: Mark big constant with ULL Andy Shevchenko
2018-02-16 21:07 ` [PATCH v2 2/9] lib/vsprintf: Make dec_spec global Andy Shevchenko
2018-04-11 9:44 ` Petr Mladek
2018-02-16 21:07 ` [PATCH v2 3/9] lib/vsprintf: Make strspec global Andy Shevchenko
2018-04-11 9:44 ` Petr Mladek
2018-02-16 21:07 ` [PATCH v2 4/9] lib/vsprintf: Make flag_spec global Andy Shevchenko
2018-04-11 9:45 ` Petr Mladek
2018-02-16 21:07 ` [PATCH v2 5/9] lib/vsprintf: Move pointer_string() upper Andy Shevchenko
2018-04-11 9:45 ` Petr Mladek
2018-02-16 21:07 ` [PATCH v2 6/9] lib/vsprintf: Deduplicate pointer_string() Andy Shevchenko
2018-04-11 9:46 ` Petr Mladek
2018-02-16 21:07 ` [PATCH v2 7/9] lib/vsprintf: Replace space with '_' before crng is ready Andy Shevchenko
2018-02-20 2:57 ` [此邮件可能存在风险] " Yang, Shunyong
2018-04-11 9:47 ` Petr Mladek
2018-02-16 21:07 ` [PATCH v2 8/9] lib/vsprintf: Remove useless NULL checks Andy Shevchenko
2018-02-27 15:50 ` Petr Mladek
2018-02-27 17:35 ` Andy Shevchenko
2018-02-28 10:04 ` Petr Mladek
2018-02-28 10:42 ` Andy Shevchenko
2018-03-02 12:51 ` Petr Mladek
2018-03-02 12:53 ` [PATCH] vsprintf: Make "null" pointer dereference more robust Petr Mladek
2018-03-02 14:17 ` Andy Shevchenko
2018-03-05 14:53 ` Petr Mladek
2018-03-29 15:13 ` Petr Mladek
2018-03-29 16:11 ` Joe Perches
2018-03-05 15:16 ` Rasmus Villemoes
2018-03-05 15:25 ` Andy Shevchenko
2018-03-06 9:25 ` Petr Mladek
2018-03-06 9:56 ` Andy Shevchenko
2018-03-07 15:52 ` Petr Mladek
2018-03-07 18:18 ` Andy Shevchenko
2018-03-07 18:34 ` Linus Torvalds
2018-03-08 14:18 ` Petr Mladek
2018-03-08 16:45 ` Linus Torvalds
2018-03-08 17:26 ` Linus Torvalds
2018-03-09 15:01 ` Petr Mladek
2018-03-09 19:05 ` Linus Torvalds
2018-03-14 14:09 ` [PATCH v3] vsprintf: Prevent crash when dereferencing invalid pointers Petr Mladek
2018-03-14 22:12 ` Rasmus Villemoes
2018-03-15 15:07 ` Petr Mladek
2018-03-15 17:07 ` Steven Rostedt
2018-03-15 17:06 ` Steven Rostedt
2018-03-15 0:57 ` Sergey Senozhatsky
2018-03-15 7:58 ` Sergey Senozhatsky
2018-03-15 8:03 ` Sergey Senozhatsky
2018-03-15 17:01 ` Steven Rostedt
2018-03-16 1:18 ` Sergey Senozhatsky
2018-03-16 1:35 ` Linus Torvalds
2018-03-16 5:53 ` Sergey Senozhatsky
2018-03-16 8:55 ` Petr Mladek
2018-03-16 14:32 ` Steven Rostedt
2018-03-17 1:29 ` Sergey Senozhatsky
2018-03-15 13:07 ` Andy Shevchenko
2018-03-15 13:09 ` Andy Shevchenko
2018-03-15 15:26 ` Petr Mladek
2018-03-16 18:19 ` Andy Shevchenko
2018-03-29 14:53 ` Petr Mladek
2018-04-02 14:15 ` Andy Shevchenko
2018-04-03 1:12 ` Sergey Senozhatsky
2018-04-03 11:52 ` Petr Mladek
2018-04-03 11:56 ` Andy Shevchenko
2018-04-03 13:57 ` Sergey Senozhatsky
2018-04-03 11:46 ` Petr Mladek
2018-04-03 11:54 ` Andy Shevchenko
2018-04-03 13:13 ` Petr Mladek
2018-04-03 13:40 ` Andy Shevchenko
2018-04-03 14:50 ` Petr Mladek
2018-03-15 14:48 ` kbuild test robot
2018-03-15 20:26 ` kbuild test robot
2018-03-06 18:11 ` Adam Borowski [this message]
2018-03-06 18:11 ` [PATCH 2/2] vsprintf: don't dereference pointers to the first or last page Adam Borowski
2018-03-07 13:22 ` Andy Shevchenko
2018-03-07 13:17 ` [PATCH 1/2] vsprintf: distinguish between (null), (err) and (invalid) pointer derefs Andy Shevchenko
2018-03-07 13:42 ` Adam Borowski
2018-03-07 13:29 ` Andy Shevchenko
2018-03-02 14:15 ` [PATCH v2 8/9] lib/vsprintf: Remove useless NULL checks Andy Shevchenko
2018-03-05 14:57 ` Petr Mladek
2018-02-28 10:44 ` Andy Shevchenko
2018-03-01 14:56 ` Andy Shevchenko
2018-02-16 21:07 ` [PATCH v2 9/9] lib/vsprintf: Mark expected switch fall-through Andy Shevchenko
2018-04-11 9:47 ` Petr Mladek
2018-02-18 12:58 ` [PATCH v2 1/9] lib/test_printf: Mark big constant with ULL Luc Van Oostenryck
2018-02-18 14:20 ` Andy Shevchenko
2018-02-19 15:24 ` Andy Shevchenko
2018-04-11 9:41 ` Petr Mladek
2018-02-18 21:52 ` Tobin C. Harding
2018-02-18 23:55 ` Andy Shevchenko
2018-03-06 18:22 [PATCH 1/2] vsprintf: distinguish between (null), (err) and (invalid) pointer derefs Alexey Dobriyan
2018-03-06 18:42 ` Adam Borowski
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