Arjan van de Ven writes:
On Sat, 27 Feb 2010 21:47:42 +0100
Roel Kluin roel.kl...@gmail.com wrote:
+void secure_bzero(void *p, size_t n)
+{
+ memset(p, 0, n);
+ ARRAY_PREVENT_DSE(p, n);
+}
+EXPORT_SYMBOL(secure_bzero);
please don't introduce bzero again to the
On Mon, Mar 1, 2010 at 11:32 AM, Mikael Pettersson mi...@it.uu.se wrote:
Arjan van de Ven writes:
On Sat, 27 Feb 2010 21:47:42 +0100
Roel Kluin roel.kl...@gmail.com wrote:
+void secure_bzero(void *p, size_t n)
+{
+ memset(p, 0, n);
+ ARRAY_PREVENT_DSE(p, n);
+}
On Sun, Feb 28, 2010 at 09:15:11PM -0800, Arjan van de Ven wrote:
On Sat, 27 Feb 2010 21:47:42 +0100
Roel Kluin roel.kl...@gmail.com wrote:
+void secure_bzero(void *p, size_t n)
+{
+ memset(p, 0, n);
+ ARRAY_PREVENT_DSE(p, n);
+}
+EXPORT_SYMBOL(secure_bzero);
please don't
Every byte in the [p,p+n[ range must be used. If you only use the
first byte, via e.g. asm( :: m(*(char*)p)), then the compiler
_will_ skip scrubbing bytes beyond the first. This works with
gcc-3.2.3 up to gcc-4.4.3.
You forgot to credit Mikael who did all the hard work figuring
this out?
Andi Kleen wrote:
Every byte in the [p,p+n[ range must be used. If you only use the
first byte, via e.g. asm( :: m(*(char*)p)), then the compiler
_will_ skip scrubbing bytes beyond the first. This works with
gcc-3.2.3 up to gcc-4.4.3.
You forgot to credit Mikael who did all the hard work
On Sat, 27 Feb 2010 21:47:42 +0100
Roel Kluin roel.kl...@gmail.com wrote:
+void secure_bzero(void *p, size_t n)
+{
+ memset(p, 0, n);
+ ARRAY_PREVENT_DSE(p, n);
+}
+EXPORT_SYMBOL(secure_bzero);
please don't introduce bzero again to the kernel;
make it secure_memset() please.
--
Due to optimization A call to memset() may be removed as a dead store when
the buffer is not used after its value is overwritten. The new function
secure_bzero() ensures a section of memory is padded with zeroes.
From the GCC manual, section 5.37:
If your assembler instructions access memory in
