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powerpc/mm: Don't log user reads to 0xffffffff 

[ Upstream commit 0f9aee0cb9 ]

Running vdsotest leaves many times the following log:

  [   79.629901] vdsotest[396]: User access of kernel address (ffffffff) - exploit attempt? (uid: 0)

A pointer set to (-1) is likely a programming error similar to
a NULL pointer and is not worth logging as an exploit attempt.

Don't log user accesses to 0xffffffff.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0728849e826ba16f1fbd6fa7f5c6cc87bd64e097.1577087627.git.christophe.leroy@c-s.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Christophe Leroy 2019-12-23 07:54:22 +00:00 committed by Greg Kroah-Hartman
parent 3ce3df5d00
commit 7288d5338c
1 changed files with 3 additions and 0 deletions
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3
arch/powerpc/mm/fault.c
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@ -354,6 +354,9 @@ static void sanity_check_fault(bool is_write, bool is_user,
* Userspace trying to access kernel address, we get PROTFAULT for that.
*/
if (is_user && address >= TASK_SIZE) {
if ((long)address == -1)
return;
pr_crit_ratelimited("%s[%d]: User access of kernel address (%lx) - exploit attempt? (uid: %d)\n",
current->comm, current->pid, address,
from_kuid(&init_user_ns, current_uid()));