[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190221093601.27920-3-ruscur@russell.cc>
Date: Thu, 21 Feb 2019 20:35:56 +1100
From: Russell Currey <ruscur@...sell.cc>
To: linuxppc-dev@...ts.ozlabs.org
Cc: mpe@...erman.id.au,
npiggin@...il.com,
christophe.leroy@....fr,
kernel-hardening@...ts.openwall.com
Subject: [PATCH 2/7] powerpc: Add skeleton for Kernel Userspace Execution Prevention
From: Christophe Leroy <christophe.leroy@....fr>
This patch adds a skeleton for Kernel Userspace Execution Prevention.
Then subarches implementing it have to define CONFIG_PPC_HAVE_KUEP
and provide setup_kuep() function.
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
Documentation/admin-guide/kernel-parameters.txt | 2 +-
arch/powerpc/include/asm/kup.h | 6 ++++++
arch/powerpc/mm/fault.c | 3 ++-
arch/powerpc/mm/init-common.c | 11 +++++++++++
arch/powerpc/platforms/Kconfig.cputype | 12 ++++++++++++
5 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 858b6c0b9a15..8448a56a9eb9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2812,7 +2812,7 @@
Disable SMAP (Supervisor Mode Access Prevention)
even if it is supported by processor.
- nosmep [X86]
+ nosmep [X86,PPC]
Disable SMEP (Supervisor Mode Execution Prevention)
even if it is supported by processor.
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index 7a88b8b9b54d..af4b5f854ca4 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -6,6 +6,12 @@
void setup_kup(void);
+#ifdef CONFIG_PPC_KUEP
+void setup_kuep(bool disabled);
+#else
+static inline void setup_kuep(bool disabled) { }
+#endif
+
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_POWERPC_KUP_H_ */
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 887f11bcf330..ad65e336721a 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -230,8 +230,9 @@ static bool bad_kernel_fault(bool is_exec, unsigned long error_code,
if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT |
DSISR_PROTFAULT))) {
printk_ratelimited(KERN_CRIT "kernel tried to execute"
- " exec-protected page (%lx) -"
+ " %s page (%lx) -"
"exploit attempt? (uid: %d)\n",
+ address >= TASK_SIZE ? "exec-protected" : "user",
address, from_kuid(&init_user_ns,
current_uid()));
}
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index 36d28e872289..83f95a5565d6 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -26,8 +26,19 @@
#include <asm/pgtable.h>
#include <asm/kup.h>
+static bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
+
+static int __init parse_nosmep(char *p)
+{
+ disable_kuep = true;
+ pr_warn("Disabling Kernel Userspace Execution Prevention\n");
+ return 0;
+}
+early_param("nosmep", parse_nosmep);
+
void __init setup_kup(void)
{
+ setup_kuep(disable_kuep);
}
#define CTOR(shift) static void ctor_##shift(void *addr) \
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 8c7464c3f27f..410c3443652c 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -339,6 +339,18 @@ config PPC_RADIX_MMU_DEFAULT
If you're unsure, say Y.
+config PPC_HAVE_KUEP
+ bool
+
+config PPC_KUEP
+ bool "Kernel Userspace Execution Prevention"
+ depends on PPC_HAVE_KUEP
+ default y
+ help
+ Enable support for Kernel Userspace Execution Prevention (KUEP)
+
+ If you're unsure, say Y.
+
config ARCH_ENABLE_HUGEPAGE_MIGRATION
def_bool y
depends on PPC_BOOK3S_64 && HUGETLB_PAGE && MIGRATION
--
2.20.1
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
