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From: Laurent Alfonsi <laurent.alfonsi@st.com>
To: Cedric VINCENT <cedric.vincent@st.com>
Cc: Riku Voipio <riku.voipio@iki.fi>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	Richard Henderson <rth@twiddle.net>
Subject: Re: [Qemu-devel] [PATCH] linux-user: Define AT_RANDOM to support target	dynamic linkers that do ASLR
Date: Mon, 13 Jun 2011 14:03:40 +0200	[thread overview]
Message-ID: <4DF5FC9C.4050701@st.com> (raw)
In-Reply-To: <20110603064619.GA7025@gnx2503>

>>          unsigned char k_rand_bytes[16];
>>          elf_addr_t __user *u_rand_bytes;
>> ...
>>          /*
>>           * Generate 16 random bytes for userspace PRNG seeding.
>>           */
>>          get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
>>          u_rand_bytes = (elf_addr_t __user *)
>>                         STACK_ALLOC(p, sizeof(k_rand_bytes));
>>          if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
>>                  return -EFAULT;
>> ...
>>          NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
> It's clearer to me now, thanks.
It is fine with me, I also understand better now.
And this now brings me to another point : In that case, it might have 
sense to also add the auxv AT_RANDOM_SIZE.
     http://sources.redhat.com/ml/libc-alpha/2008-10/msg00016.html

>> I suggest at minimum a command-line argument to force a
>> particular AT_RANDOM value, for repeatability.
Yep, I agree.

Laurent.

  reply	other threads:[~2011-06-13 12:04 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-01 11:42 [Qemu-devel] [PATCH] linux-user: Define AT_RANDOM to support target dynamic linkers that do ASLR Cédric VINCENT
2011-06-01 13:26 ` Richard Henderson
2011-06-01 13:47   ` cedric.vincent
2011-06-01 14:35     ` [Qemu-devel] [PATCH v2] " Cédric VINCENT
2011-06-01 15:33     ` [Qemu-devel] [PATCH] " Richard Henderson
2011-06-03  6:46       ` cedric.vincent
2011-06-13 12:03         ` Laurent Alfonsi [this message]
2011-06-13 15:53           ` Richard Henderson
2011-06-20  6:43       ` [Qemu-devel] [PATCH v3] linux-user: Define AT_RANDOM to support target stack protection mechanism Cédric VINCENT

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