diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a53df74589e52489148641bdb62e4528f0ad4bab..c45a19d654f32ca83d081dd47bad32b6978d5c43 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2839,7 +2839,7 @@
noexec=on: enable non-executable mappings (default)
noexec=off: disable non-executable mappings
- nosmap [X86]
+ nosmap [X86,PPC]
Disable SMAP (Supervisor Mode Access Prevention)
even if it is supported by processor.
diff --git a/arch/powerpc/include/asm/futex.h b/arch/powerpc/include/asm/futex.h
index 88b38b37c21b160e2dbe43da5894f145ee6a4043..3a6aa57b9d9010aa31693f27c21339a2e9c9e643 100644
--- a/arch/powerpc/include/asm/futex.h
+++ b/arch/powerpc/include/asm/futex.h
@@ -35,6 +35,7 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
{
int oldval = 0, ret;
+ allow_write_to_user(uaddr, sizeof(*uaddr));
pagefault_disable();
switch (op) {
@@ -62,6 +63,7 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
if (!ret)
*oval = oldval;
+ prevent_write_to_user(uaddr, sizeof(*uaddr));
return ret;
}
@@ -75,6 +77,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
if (!access_ok(uaddr, sizeof(u32)))
return -EFAULT;
+ allow_write_to_user(uaddr, sizeof(*uaddr));
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
"1: lwarx %1,0,%3 # futex_atomic_cmpxchg_inatomic\n\
@@ -95,6 +98,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
: "cc", "memory");
*uval = prev;
+ prevent_write_to_user(uaddr, sizeof(*uaddr));
return ret;
}
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index a2a959cb4e367b6ed72663ec01a8065af1538e77..4d78b9d8c99c0181a6cc3d0b857fce8270fd4064 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -4,6 +4,8 @@
#ifndef __ASSEMBLY__
+#include <asm/pgtable.h>
+
void setup_kup(void);
#ifdef CONFIG_PPC_KUEP
@@ -12,6 +14,36 @@ void setup_kuep(bool disabled);
static inline void setup_kuep(bool disabled) { }
#endif /* CONFIG_PPC_KUEP */
+#ifdef CONFIG_PPC_KUAP
+void setup_kuap(bool disabled);
+#else
+static inline void setup_kuap(bool disabled) { }
+static inline void allow_user_access(void __user *to, const void __user *from,
+ unsigned long size) { }
+static inline void prevent_user_access(void __user *to, const void __user *from,
+ unsigned long size) { }
+#endif /* CONFIG_PPC_KUAP */
+
+static inline void allow_read_from_user(const void __user *from, unsigned long size)
+{
+ allow_user_access(NULL, from, size);
+}
+
+static inline void allow_write_to_user(void __user *to, unsigned long size)
+{
+ allow_user_access(to, NULL, size);
+}
+
+static inline void prevent_read_from_user(const void __user *from, unsigned long size)
+{
+ prevent_user_access(NULL, from, size);
+}
+
+static inline void prevent_write_to_user(void __user *to, unsigned long size)
+{
+ prevent_user_access(to, NULL, size);
+}
+
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_POWERPC_KUP_H_ */
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 64271e562fed324fe25b8b2743c34ac5ee1fd390..6f047730e642e6caa8c187ab482ec94a5e5e2f29 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -52,10 +52,17 @@ struct pt_regs
};
};
+ union {
+ struct {
#ifdef CONFIG_PPC64
- unsigned long ppr;
- unsigned long __pad; /* Maintain 16 byte interrupt stack alignment */
+ unsigned long ppr;
+#endif
+#ifdef CONFIG_PPC_KUAP
+ unsigned long kuap;
#endif
+ };
+ unsigned long __pad[2]; /* Maintain 16 byte interrupt stack alignment */
+ };
};
#endif
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 4d6d905e913809ef018ecc57a1c31a2845fdfd7f..76f34346b642d1b4f9aa8ac7e1c3a04f7c7b8646 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -6,6 +6,7 @@
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/extable.h>
+#include <asm/kup.h>
/*
* The fs value determines whether argument validity checking should be
@@ -140,6 +141,7 @@ extern long __put_user_bad(void);
#define __put_user_size(x, ptr, size, retval) \
do { \
retval = 0; \
+ allow_write_to_user(ptr, size); \
switch (size) { \
case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
@@ -147,6 +149,7 @@ do { \
case 8: __put_user_asm2(x, ptr, retval); break; \
default: __put_user_bad(); \
} \
+ prevent_write_to_user(ptr, size); \
} while (0)
#define __put_user_nocheck(x, ptr, size) \
@@ -239,6 +242,7 @@ do { \
__chk_user_ptr(ptr); \
if (size > sizeof(x)) \
(x) = __get_user_bad(); \
+ allow_read_from_user(ptr, size); \
switch (size) { \
case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
@@ -246,6 +250,7 @@ do { \
case 8: __get_user_asm2(x, ptr, retval); break; \
default: (x) = __get_user_bad(); \
} \
+ prevent_read_from_user(ptr, size); \
} while (0)
/*
@@ -305,15 +310,21 @@ extern unsigned long __copy_tofrom_user(void __user *to,
static inline unsigned long
raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
- return __copy_tofrom_user(to, from, n);
+ unsigned long ret;
+
+ allow_user_access(to, from, n);
+ ret = __copy_tofrom_user(to, from, n);
+ prevent_user_access(to, from, n);
+ return ret;
}
#endif /* __powerpc64__ */
static inline unsigned long raw_copy_from_user(void *to,
const void __user *from, unsigned long n)
{
+ unsigned long ret;
if (__builtin_constant_p(n) && (n <= 8)) {
- unsigned long ret = 1;
+ ret = 1;
switch (n) {
case 1:
@@ -338,14 +349,18 @@ static inline unsigned long raw_copy_from_user(void *to,
}
barrier_nospec();
- return __copy_tofrom_user((__force void __user *)to, from, n);
+ allow_read_from_user(from, n);
+ ret = __copy_tofrom_user((__force void __user *)to, from, n);
+ prevent_read_from_user(from, n);
+ return ret;
}
static inline unsigned long raw_copy_to_user(void __user *to,
const void *from, unsigned long n)
{
+ unsigned long ret;
if (__builtin_constant_p(n) && (n <= 8)) {
- unsigned long ret = 1;
+ ret = 1;
switch (n) {
case 1:
@@ -365,17 +380,24 @@ static inline unsigned long raw_copy_to_user(void __user *to,
return 0;
}
- return __copy_tofrom_user(to, (__force const void __user *)from, n);
+ allow_write_to_user(to, n);
+ ret = __copy_tofrom_user(to, (__force const void __user *)from, n);
+ prevent_write_to_user(to, n);
+ return ret;
}
extern unsigned long __clear_user(void __user *addr, unsigned long size);
static inline unsigned long clear_user(void __user *addr, unsigned long size)
{
+ unsigned long ret = size;
might_fault();
- if (likely(access_ok(addr, size)))
- return __clear_user(addr, size);
- return size;
+ if (likely(access_ok(addr, size))) {
+ allow_write_to_user(addr, size);
+ ret = __clear_user(addr, size);
+ prevent_write_to_user(addr, size);
+ }
+ return ret;
}
extern long strncpy_from_user(char *dst, const char __user *src, long count);
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 86a61e5f8285bfb237abdcbb44d71df2174792a6..66202e02fee26a9153539679daa5752b8761ec2c 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -332,6 +332,10 @@ int main(void)
STACK_PT_REGS_OFFSET(_PPR, ppr);
#endif /* CONFIG_PPC64 */
+#ifdef CONFIG_PPC_KUAP
+ STACK_PT_REGS_OFFSET(STACK_REGS_KUAP, kuap);
+#endif
+
#if defined(CONFIG_PPC32)
#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
DEFINE(EXC_LVL_SIZE, STACK_EXC_LVL_FRAME_SIZE);
diff --git a/arch/powerpc/lib/checksum_wrappers.c b/arch/powerpc/lib/checksum_wrappers.c
index 890d4ddd91d619c33d21f41f7b39db7621ec443c..bb9307ce2440d2e45edd6352c8fa72fed6d6dce9 100644
--- a/arch/powerpc/lib/checksum_wrappers.c
+++ b/arch/powerpc/lib/checksum_wrappers.c
@@ -29,6 +29,7 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst,
unsigned int csum;
might_sleep();
+ allow_read_from_user(src, len);
*err_ptr = 0;
@@ -60,6 +61,7 @@ __wsum csum_and_copy_from_user(const void __user *src, void *dst,
}
out:
+ prevent_read_from_user(src, len);
return (__force __wsum)csum;
}
EXPORT_SYMBOL(csum_and_copy_from_user);
@@ -70,6 +72,7 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
unsigned int csum;
might_sleep();
+ allow_write_to_user(dst, len);
*err_ptr = 0;
@@ -97,6 +100,7 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
}
out:
+ prevent_write_to_user(dst, len);
return (__force __wsum)csum;
}
EXPORT_SYMBOL(csum_and_copy_to_user);
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 3384354abc1d2f769dc1d8e2a1f5070fdb29fc9d..463d1e9d026e90a8220a02f970f8879ef1ad61e2 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -223,9 +223,11 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr,
}
/* Is this a bad kernel fault ? */
-static bool bad_kernel_fault(bool is_exec, unsigned long error_code,
+static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code,
unsigned long address)
{
+ int is_exec = TRAP(regs) == 0x400;
+
/* NX faults set DSISR_PROTFAULT on the 8xx, DSISR_NOEXEC_OR_G on others */
if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT |
DSISR_PROTFAULT))) {
@@ -234,7 +236,15 @@ static bool bad_kernel_fault(bool is_exec, unsigned long error_code,
address,
from_kuid(&init_user_ns, current_uid()));
}
- return is_exec || (address >= TASK_SIZE);
+
+ if (!is_exec && address < TASK_SIZE && (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()));
+ }
+
+ return is_exec || (address >= TASK_SIZE) || !search_exception_tables(regs->nip);
}
static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address,
@@ -454,9 +464,10 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
/*
* The kernel should never take an execute fault nor should it
- * take a page fault to a kernel address.
+ * take a page fault to a kernel address or a page fault to a user
+ * address outside of dedicated places
*/
- if (unlikely(!is_user && bad_kernel_fault(is_exec, error_code, address)))
+ if (unlikely(!is_user && bad_kernel_fault(regs, error_code, address)))
return SIGSEGV;
/*
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index 83f95a5565d670239b3b30504e8fdf16ddc0071d..ecaedfff99921d45f3ce82b9e94e1b0466f66ee4 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -27,6 +27,7 @@
#include <asm/kup.h>
static bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
+static bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
static int __init parse_nosmep(char *p)
{
@@ -36,9 +37,18 @@ static int __init parse_nosmep(char *p)
}
early_param("nosmep", parse_nosmep);
+static int __init parse_nosmap(char *p)
+{
+ disable_kuap = true;
+ pr_warn("Disabling Kernel Userspace Access Protection\n");
+ return 0;
+}
+early_param("nosmap", parse_nosmap);
+
void __init setup_kup(void)
{
setup_kuep(disable_kuep);
+ setup_kuap(disable_kuap);
}
#define CTOR(shift) static void ctor_##shift(void *addr) \
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 7d30bbbaa3c1a3086a2be40862d0ab9de5c2c259..457fc3a5ed93dc03b05795bf6785b31e835d84ef 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -357,6 +357,18 @@ config PPC_KUEP
If you're unsure, say Y.
+config PPC_HAVE_KUAP
+ bool
+
+config PPC_KUAP
+ bool "Kernel Userspace Access Protection"
+ depends on PPC_HAVE_KUAP
+ default y
+ help
+ Enable support for Kernel Userspace Access Protection (KUAP)
+
+ If you're unsure, say Y.
+
config ARCH_ENABLE_HUGEPAGE_MIGRATION
def_bool y
depends on PPC_BOOK3S_64 && HUGETLB_PAGE && MIGRATION