zatimend has reported that in his environment (3.16/gcc4.8.3/corei7)
memset() calls which clear out sensitive data in extract_{buf,entropy,
entropy_user}() in random driver are being optimized away by gcc.

Add a helper memzero_explicit() (similarly as explicit_bzero() variants)
that can be used in such cases where a variable with sensitive data is
being cleared out in the end. Other use cases might also be in crypto
code. [ I have put this into lib/string.c though, as it's always built-in
and doesn't need any dependencies then. ]

Fixes kernel bugzilla: 82041

Reported-by: zatimend@hotmail.co.uk
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

For strncpy() and friends the source string may or may not have an actual
NUL character at the end.  The documentation is confusing in this because
it specifically mentions that you are passing a "NUL-terminated" string.
Wikipedia says that "C-string" is an alternative name we can use instead.

http://en.wikipedia.org/wiki/Null-terminated_stringSigned-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The strchrnul() variant helpfully returns a the end of the string
instead of a NULL if the requested character is not found. This can
simplify string parsing code since it doesn't need to expicitly check
for a NULL return. If a valid string pointer is passed in, then a valid
null terminated string will always come back out.
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

In LTO symbols implicitely referenced by the compiler need
to be visible. Earlier these symbols were visible implicitely
from being exported, but we disabled implicit visibility fo
 EXPORTs when modules are disabled to improve code size. So
now these symbols have to be marked visible explicitely.

Do this for __stack_chk_fail (with stack protector)
and memcmp.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391845930-28580-10-git-send-email-ak@linux.intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

- Generate a 64-bit pattern more efficiently

memchr_inv needs to generate a 64-bit pattern filled with a target
character.  The operation can be done by more efficient way.

- Don't call the slow check_bytes() if the memory area is 64-bit aligned

memchr_inv compares contiguous 64-bit words with the 64-bit pattern as
much as possible.  The outside of the region is checked by check_bytes()
that scans for each byte.  Unfortunately, the first 64-bit word is
unexpectedly scanned by check_bytes() even if the memory area is aligned
to a 64-bit boundary.

Both changes were originally suggested by Eric Dumazet.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Suggested-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

With bug.h currently living right in linux/kernel.h there
are files that use BUG_ON and friends but are not including
the header explicitly.  Fix them up so we can remove the
presence in kernel.h file.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Commit 84c95c9a ("string: on strstrip(), first remove leading spaces
before running over str") improved the performance of the strim()
function.

Unfortunately this changed the semantics of strim() and broke my code.
Before the patch it was possible to use strim() without using the return
value for removing trailing spaces from strings that had either only
blanks or only trailing blanks.

Now this does not work any longer for strings that *only* have blanks.

Before patch: "   " -> ""    (empty string)
After patch:  "   " -> "   " (no change)

I think we should remove your patch to restore the old behavior.

The description (lib/string.c):

 * Note that the first trailing whitespace is replaced with a %NUL-terminator

=> The first trailing whitespace of a string that only has whitespace
   characters is the first whitespace

The patch restores the old strim() semantics.
Signed-off-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Andre Goddard Rosa <andre.goddard@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memchr_inv() is mainly used to check whether the whole buffer is filled
with just a specified byte.

The function name and prototype are stolen from logfs and the
implementation is from SLUB.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Acked-by: NPekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: NJoern Engel <joern@logfs.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a rename of the usr_strtobool proposal, which was a renamed,
relocated and fixed version of previous kstrtobool RFC
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This is a rename of the usr_strtobool proposal, which was a renamed,
relocated and fixed version of previous kstrtobool RFC
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Joe Perches <joe@perches.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Removes 32 bytes on core2 with gcc 4.4.1:
   text    data     bss     dec     hex filename
   3196       0       0    3196     c7c lib/string-BEFORE.o
   3164       0       0    3164     c5c lib/string-AFTER.o
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It differs strstr() in that it limits the length to be searched
in the first string.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8743.6030805@cn.fujitsu.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Fix kernel-doc warnings (@arg name) in string.c::skip_spaces().

  Warning(lib/string.c:347): No description found for parameter 'str'
  Warning(lib/string.c:347): Excess function parameter 's' description in 'skip_spaces'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Recently, We marked strstrip() as must_check.  because it was frequently
misused and it should be checked.  However, we found one exception.
scsi/ipr.c intentionally ignore return value of strstrip.  Because it
wishes to keep the whitespace at the beginning.

Thus we need to keep with and without checked whitespace trim function.
This patch adds a new strim() and changes ipr.c to use it.

[akpm@linux-foundation.org: coding-style fixes]
Suggested-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

... so that strlen() iterates over a smaller string comprising of the
remaining characters only.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On the following sentence:
    while (*s && isspace(*s))
        s++;

If *s == 0, isspace() evaluates to ((_ctype[*s] & 0x20) != 0), which
evaluates to ((0x08 & 0x20) != 0) which equals to 0 as well.
If *s == 1, we depend on isspace() result anyway. In other words,
"a char equals zero is never a space", so remove this check.

Also, *s != 0 is most common case (non-null string).

Fixed const return as noticed by Jan Engelhardt and James Bottomley.
Fixed unnecessary extra cast on strstrip() as noticed by Jan Engelhardt.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Doing the strcmp return value as

	signed char __res = *cs - *ct;

is wrong for two reasons.  The subtraction can overflow because __res
doesn't use a type big enough.  Moreover the compared bytes should be
interpreted as unsigned char as specified by POSIX.

The same problem is fixed in strncmp.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a new sysfs_streq() string comparison function, which ignores
the trailing newlines found in sysfs inputs.  By example:

	sysfs_streq("a", "b")	==> false
	sysfs_streq("a", "a")	==> true
	sysfs_streq("a", "a\n")	==> true
	sysfs_streq("a\n", "a")	==> true

This is intended to simplify parsing of sysfs inputs, letting them
avoid the need to manually strip off newlines from inputs.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NGreg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have several platforms using local copies of identical
code.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
source files, including:

  * make multi-line initial descriptions single line
  * denote some function names, constants and structs as such
  * change erroneous opening '/*' to '/**' in a few places
  * reword some text for clarity
Signed-off-by: NRobert P. J. Day <rpjday@mindspring.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

strstrip() does not remove the last blank from strings which only consist
of blanks.

Example:
char string[] = "  ";
strstrip(string);

results in " ", but should produce an empty string!

The following patch solves this problem:
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NMichael Holzheu <holzheu@de.ibm.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by Joern Engel <joern@wh.fh-wedel.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a new strstrip() function to lib/string.c for removing leading and
trailing whitespace from a string.

Cc: Michael Holzheu <holzheu@de.ibm.com>
Acked-by: NIngo Oeser <ioe-lkml@rameria.de>
Acked-by: NJoern Engel <joern@wohnheim.fh-wedel.de>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NMichael Holzheu <HOLZHEU@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

lib/string.c: In function 'memcpy':
lib/string.c:470: warning: initialization discards qualifiers from pointer =
target type
Signed-off-by: NJan-Benedict Glaw <jbglaw@lug-owl.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Some string functions were safely overrideable in lib/string.c, but their
corresponding declarations in linux/string.h were not.  Correct this, and
make strcspn overrideable.

Odds of someone wanting to do optimized assembly of these are small, but
for the sake of cleanliness, might as well bring them into line with the
rest of the file.
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

While cleaning up parisc_ksyms.c earlier, I noticed that strpbrk wasn't
being exported from lib/string.c.  Investigating further, I noticed a
changeset that removed its export and added it to _ksyms.c on a few more
architectures.  The justification was that "other arches do it."

I think this is wrong, since no architecture currently defines
__HAVE_ARCH_STRPBRK, there's no reason for any of them to be exporting it
themselves.  Therefore, consolidate the export to lib/string.c.
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Sam's tree includes a new check, which found that we're exporting strpbrk()
multiple times.

It seems that the convention is that this is exported from the arch files, so
reove the lib/string.c export.

Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

A couple of (char *) casts removed in a previous cleanup patch in
lib/string.c:memmove() were actually useful, as they suppressed a couple of
warnings:

	assignment discards qualifiers from pointer target type

Fix by declaring the local variable const in the first place, so casts
aren't needed to strip the const qualifier.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The first two hunks of the patch really belongs in patch 1, but I missed
them on the first pass and instead of redoing all 3 patches I stuck them in
this one.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Removes a few pointless register keywords.  register is merely a compiler
hint that access to the variable should be optimized, but gcc (3.3.6 in my
case) generates the exact same code with and without the keyword, and even
if gcc did something different with register present I think it is doubtful
we would want to optimize access to these variables - especially since this
is generic library code and there are supposed to be optimized versions in
asm/ for anything that really matters speed wise.

(akpm: iirc, keyword register is a gcc no-op unless using -O0)
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Removes some blank lines, removes some trailing whitespace, adds spaces
after commas and a few similar changes.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

this clarifies the documentation on the behavier of strncpy().
Signed-off-by: NDomen Puncer <domen@coderock.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In include/asm-x86_64/string.h there are such comments:

/* Use C out of line version for memcmp */
#define memcmp __builtin_memcmp
int memcmp(const void * cs,const void * ct,size_t count);

This would mean that if the compiler does not decide to use __builtin_memcmp,
it emits a call to memcmp to be satisfied by the C out-of-line version in
lib/string.c.  What happens is that after preprocessing, in lib/string.i you
may find the definition of "__builtin_strcmp".

Actually, by accident, in the object you will find the definition of strcmp
and such (maybe a trick intended to redirect calls to __builtin_memcmp to the
default memcmp when the definition is not expanded); however, this particular
case is not a documented feature as far as I can see.

Also, the EXPORT_SYMBOL does not work, so it's duplicated in the arch.

I simply added some #undef to lib/string.c and removed the (now duplicated)
exports in x86-64 and UML/x86_64 subarchs (the second ones are introduced by
another patch I just posted for -mm).
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!