2016-12-16 21:07:10

by Kees Cook

Subject: [PATCH] latent_entropy: fix ARM build error on earlier gcc

This fixes build errors seen on gcc-4.9.3 or gcc-5.3.1 for an ARM:

arm-soc/init/initramfs.c: In function 'error':
arm-soc/init/initramfs.c:50:1: error: unrecognizable insn:
}
^
(insn 26 25 27 5 (set (reg:SI 111 [ local_entropy.243 ])
(rotatert:SI (reg:SI 116 [ local_entropy.243 ])
(const_int -30 [0xffffffffffffffe2]))) -1
(nil))

Patch from PaX Team <[email protected]>

Reported-by: Arnd Bergmann <[email protected]>
Reported-by: Brad Spengler <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
scripts/gcc-plugins/latent_entropy_plugin.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c
index ff1939b804ae..eb1964084ccd 100644
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -328,9 +328,9 @@ static enum tree_code get_op(tree *rhs)
op = LROTATE_EXPR;
/*
* This code limits the value of random_const to
- * the size of a wide int for the rotation
+ * the size of a long for the rotation
*/
- random_const &= HOST_BITS_PER_WIDE_INT - 1;
+ random_const %= TYPE_PRECISION(long_unsigned_type_node);
break;
}

--
2.7.4


--
Kees Cook
Nexus Security

2016-12-16 22:17:41

by PaX Team

Subject: Re: [PATCH] latent_entropy: fix ARM build error on earlier gcc

On 16 Dec 2016 at 13:06, Kees Cook wrote:

> This fixes build errors seen on gcc-4.9.3 or gcc-5.3.1 for an ARM:
>
> arm-soc/init/initramfs.c: In function 'error':
> arm-soc/init/initramfs.c:50:1: error: unrecognizable insn:
> }
> ^
> (insn 26 25 27 5 (set (reg:SI 111 [ local_entropy.243 ])
> (rotatert:SI (reg:SI 116 [ local_entropy.243 ])
> (const_int -30 [0xffffffffffffffe2]))) -1
> (nil))
>
> Patch from PaX Team <[email protected]>
>
> Reported-by: Arnd Bergmann <[email protected]>
> Reported-by: Brad Spengler <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>

Cc: [email protected] perhaps?

2016-12-16 22:20:09

by Kees Cook

Subject: Re: [PATCH] latent_entropy: fix ARM build error on earlier gcc

On Fri, Dec 16, 2016 at 2:17 PM, PaX Team <[email protected]> wrote:
> On 16 Dec 2016 at 13:06, Kees Cook wrote:
>
>> This fixes build errors seen on gcc-4.9.3 or gcc-5.3.1 for an ARM:
>>
>> arm-soc/init/initramfs.c: In function 'error':
>> arm-soc/init/initramfs.c:50:1: error: unrecognizable insn:
>> }
>> ^
>> (insn 26 25 27 5 (set (reg:SI 111 [ local_entropy.243 ])
>> (rotatert:SI (reg:SI 116 [ local_entropy.243 ])
>> (const_int -30 [0xffffffffffffffe2]))) -1
>> (nil))
>>
>> Patch from PaX Team <[email protected]>
>>
>> Reported-by: Arnd Bergmann <[email protected]>
>> Reported-by: Brad Spengler <[email protected]>
>> Signed-off-by: Kees Cook <[email protected]>
>
> Cc: [email protected] perhaps?

Ah yes, good catch.

-Kees

--
Kees Cook
Nexus Security