[PATCH] fix typo/thinko in get_random_bytes()

[PATCH] fix typo/thinko in get_random_bytes()

[Luck, Tony]

If there is an architecture-specific random number generator we use
it to acquire randomness one "long" at a time. We should put these
random words into consecutive words in the result buffer - not just
overwrite the first word again and again.

Signed-off-by: Tony Luck <tony.luck@intel.com>

---

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 63e19ba..6035ab8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -941,7 +941,7 @@ void get_random_bytes(void *buf, int nbytes)
 		if (!arch_get_random_long(&v))
 			break;
 		
-		memcpy(buf, &v, chunk);
+		memcpy(p, &v, chunk);
 		p += chunk;
 		nbytes -= chunk;
 	}

Re: [PATCH] fix typo/thinko in get_random_bytes()

[H. Peter Anvin]

On 11/16/2011 10:50 AM, Luck, Tony wrote:
> If there is an architecture-specific random number generator we use
> it to acquire randomness one "long" at a time. We should put these
> random words into consecutive words in the result buffer - not just
> overwrite the first word again and again.
> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>

Ouch.  Good catch.  This, I guess, is the downside of doing this only on
the kernel paths... made this kind of errors harder to catch.

Acked-by: H. Peter Anvin <hpa@zytor.com>

Linus, do you want to take this one or should I put it in the urgent
queue in tip?

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

Re: [PATCH] fix typo/thinko in get_random_bytes()

[Thomas Gleixner]

On Wed, 16 Nov 2011, H. Peter Anvin wrote:

> On 11/16/2011 10:50 AM, Luck, Tony wrote:
> > If there is an architecture-specific random number generator we use
> > it to acquire randomness one "long" at a time. We should put these
> > random words into consecutive words in the result buffer - not just
> > overwrite the first word again and again.
> > 
> > Signed-off-by: Tony Luck <tony.luck@intel.com>
> 
> Ouch.  Good catch.  This, I guess, is the downside of doing this only on
> the kernel paths... made this kind of errors harder to catch.
> 
> Acked-by: H. Peter Anvin <hpa@zytor.com>

Acked-by: Thomas Gleixner <tglx@linutronix.de>

Re: [PATCH] fix typo/thinko in get_random_bytes()

[H. Peter Anvin]

On 11/16/2011 11:41 AM, Thomas Gleixner wrote:
> 
> 
> On Wed, 16 Nov 2011, H. Peter Anvin wrote:
> 
>> On 11/16/2011 10:50 AM, Luck, Tony wrote:
>>> If there is an architecture-specific random number generator we use
>>> it to acquire randomness one "long" at a time. We should put these
>>> random words into consecutive words in the result buffer - not just
>>> overwrite the first word again and again.
>>>
>>> Signed-off-by: Tony Luck <tony.luck@intel.com>
>>
>> Ouch.  Good catch.  This, I guess, is the downside of doing this only on
>> the kernel paths... made this kind of errors harder to catch.
>>
>> Acked-by: H. Peter Anvin <hpa@zytor.com>
> 
> Acked-by: Thomas Gleixner <tglx@linutronix.de>

Applied to x86/urgent... I'll try to get the tip-bot back online today
if I can find the time.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

[tip:x86/urgent] random: Fix handing of arch_get_random_long in get_random_bytes()

[tip-bot for Luck, Tony]

Commit-ID:  0d2f096b8785b67c38afcf6e1fbb9674af2e05ca
Gitweb:     http://git.kernel.org/tip/0d2f096b8785b67c38afcf6e1fbb9674af2e05ca
Author:     Luck, Tony <tony.luck@intel.com>
AuthorDate: Wed, 16 Nov 2011 10:50:56 -0800
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Wed, 16 Nov 2011 16:41:02 -0800

random: Fix handing of arch_get_random_long in get_random_bytes()

If there is an architecture-specific random number generator we use
it to acquire randomness one "long" at a time. We should put these
random words into consecutive words in the result buffer - not just
overwrite the first word again and again.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/4ec4061010261a4cb0@agluck-desktop.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 drivers/char/random.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 63e19ba..6035ab8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -941,7 +941,7 @@ void get_random_bytes(void *buf, int nbytes)
 		if (!arch_get_random_long(&v))
 			break;
 		
-		memcpy(buf, &v, chunk);
+		memcpy(p, &v, chunk);
 		p += chunk;
 		nbytes -= chunk;
 	}