From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
npiggin@gmail.com
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v1 3/5] powerpc/fault: Reorder tests in bad_kernel_fault()
Date: Thu, 6 Aug 2020 17:15:30 +0000 (UTC) [thread overview]
Message-ID: <ef827b73770a7b155079393f8d8430e10a99ec94.1596734104.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <7baae4086cbb9ffb08c933b065ff7d29dbc03dd6.1596734104.git.christophe.leroy@csgroup.eu>
Check address earlier to simplify the following test.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/mm/fault.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 9ef9ee244f72..525e0c2b5406 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -210,17 +210,17 @@ static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code,
return true;
}
- if (!is_exec && address < TASK_SIZE && (error_code & DSISR_PROTFAULT) &&
+ // Kernel fault on kernel address is bad
+ if (address >= TASK_SIZE)
+ return true;
+
+ if (!is_exec && (error_code & DSISR_PROTFAULT) &&
!search_exception_tables(regs->nip)) {
pr_crit_ratelimited("Kernel attempted to access user page (%lx) - exploit attempt? (uid: %d)\n",
address,
from_kuid(&init_user_ns, current_uid()));
}
- // Kernel fault on kernel address is bad
- if (address >= TASK_SIZE)
- return true;
-
// Fault on user outside of certain regions (eg. copy_tofrom_user()) is bad
if (!search_exception_tables(regs->nip))
return true;
--
2.25.0
next prev parent reply other threads:[~2020-08-06 17:17 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-06 17:15 [PATCH v1 1/5] powerpc/mm: sanity_check_fault() should work for all, not only BOOK3S Christophe Leroy
2020-08-06 17:15 ` [PATCH v1 2/5] powerpc/fault: Unnest definition of page_fault_is_write() and page_fault_is_bad() Christophe Leroy
2020-09-08 8:44 ` Nicholas Piggin
2020-08-06 17:15 ` Christophe Leroy [this message]
2020-09-08 8:46 ` [PATCH v1 3/5] powerpc/fault: Reorder tests in bad_kernel_fault() Nicholas Piggin
2020-08-06 17:15 ` [PATCH v1 4/5] powerpc/fault: Avoid heavy search_exception_tables() verification Christophe Leroy
2020-09-08 8:54 ` Nicholas Piggin
2020-09-09 6:04 ` Aneesh Kumar K.V
2020-09-09 6:20 ` Christophe Leroy
2020-09-14 2:23 ` Nicholas Piggin
2020-08-06 17:15 ` [PATCH v1 5/5] powerpc/fault: Perform exception fixup in do_page_fault() Christophe Leroy
2020-08-06 21:07 ` kernel test robot
2020-09-08 9:13 ` Nicholas Piggin
2020-09-08 8:43 ` [PATCH v1 1/5] powerpc/mm: sanity_check_fault() should work for all, not only BOOK3S Nicholas Piggin
2020-09-08 8:56 ` Christophe Leroy
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