From 1bd46782d08b01b73df0085b51ea1021b19b44fd Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 3 Jul 2015 15:22:54 +0100 Subject: ARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants We don't want GCC optimising our memset_io(), memcpy_fromio() or memcpy_toio() variants, so we must not call one of the standard functions. Provide a separate name for our assembly memcpy() and memset() functions, and use that instead, thereby bypassing GCC's ability to optimise these operations. GCCs optimisation may introduce unaligned accesses which are invalid for device mappings. Signed-off-by: Russell King --- arch/arm/lib/memcpy.S | 2 ++ arch/arm/lib/memset.S | 2 ++ 2 files changed, 4 insertions(+) (limited to 'arch/arm/lib') diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S index 7797e81e40e0..64111bd4440b 100644 --- a/arch/arm/lib/memcpy.S +++ b/arch/arm/lib/memcpy.S @@ -61,8 +61,10 @@ /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */ +ENTRY(mmiocpy) ENTRY(memcpy) #include "copy_template.S" ENDPROC(memcpy) +ENDPROC(mmiocpy) diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S index a4ee97b5a2bf..3c65e3bd790f 100644 --- a/arch/arm/lib/memset.S +++ b/arch/arm/lib/memset.S @@ -16,6 +16,7 @@ .text .align 5 +ENTRY(mmioset) ENTRY(memset) UNWIND( .fnstart ) ands r3, r0, #3 @ 1 unaligned? @@ -133,3 +134,4 @@ UNWIND( .fnstart ) b 1b UNWIND( .fnend ) ENDPROC(memset) +ENDPROC(mmioset) -- cgit v1.2.3 From 0f64b247e63ac8c214efa6725366b42563ab138c Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 12 Aug 2015 16:45:02 +0100 Subject: ARM: 8414/1: __copy_to_user_memcpy: fix mmap semaphore usage The mmap semaphore should not be taken when page faults are disabled. Since pagefault_disable() no longer disables preemption, we now need to use faulthandler_disabled() in place of in_atomic(). Signed-off-by: Nicolas Pitre Tested-by: Mark Salter Signed-off-by: Russell King --- arch/arm/lib/uaccess_with_memcpy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/lib') diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c index 3e58d710013c..4b39af2dfda9 100644 --- a/arch/arm/lib/uaccess_with_memcpy.c +++ b/arch/arm/lib/uaccess_with_memcpy.c @@ -96,7 +96,7 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n) } /* the mmap semaphore is taken only if not in an atomic context */ - atomic = in_atomic(); + atomic = faulthandler_disabled(); if (!atomic) down_read(¤t->mm->mmap_sem); -- cgit v1.2.3 From 3fba7e23f754a9a6e639b640fa2a393712ffe1b8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 19 Aug 2015 11:02:28 +0100 Subject: ARM: uaccess: provide uaccess_save_and_enable() and uaccess_restore() Provide uaccess_save_and_enable() and uaccess_restore() to permit control of userspace visibility to the kernel, and hook these into the appropriate places in the kernel where we need to access userspace. Signed-off-by: Russell King --- arch/arm/include/asm/futex.h | 19 ++++++++-- arch/arm/include/asm/uaccess.h | 71 +++++++++++++++++++++++++++++++++++--- arch/arm/kernel/armksyms.c | 6 ++-- arch/arm/lib/clear_user.S | 6 ++-- arch/arm/lib/copy_from_user.S | 6 ++-- arch/arm/lib/copy_to_user.S | 6 ++-- arch/arm/lib/uaccess_with_memcpy.c | 4 +-- 7 files changed, 97 insertions(+), 21 deletions(-) (limited to 'arch/arm/lib') diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 5eed82809d82..6795368ad023 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -22,8 +22,11 @@ #ifdef CONFIG_SMP #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ +({ \ + unsigned int __ua_flags; \ smp_mb(); \ prefetchw(uaddr); \ + __ua_flags = uaccess_save_and_enable(); \ __asm__ __volatile__( \ "1: ldrex %1, [%3]\n" \ " " insn "\n" \ @@ -34,12 +37,15 @@ __futex_atomic_ex_table("%5") \ : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ +}) static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) { + unsigned int __ua_flags; int ret; u32 val; @@ -49,6 +55,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, smp_mb(); /* Prefetching cannot fault */ prefetchw(uaddr); + __ua_flags = uaccess_save_and_enable(); __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" "1: ldrex %1, [%4]\n" " teq %1, %2\n" @@ -61,6 +68,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, : "=&r" (ret), "=&r" (val) : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) : "cc", "memory"); + uaccess_restore(__ua_flags); smp_mb(); *uval = val; @@ -73,6 +81,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, #include #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ +({ \ + unsigned int __ua_flags = uaccess_save_and_enable(); \ __asm__ __volatile__( \ "1: " TUSER(ldr) " %1, [%3]\n" \ " " insn "\n" \ @@ -81,12 +91,15 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, __futex_atomic_ex_table("%5") \ : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ +}) static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval) { + unsigned int __ua_flags; int ret = 0; u32 val; @@ -94,6 +107,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, return -EFAULT; preempt_disable(); + __ua_flags = uaccess_save_and_enable(); __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" "1: " TUSER(ldr) " %1, [%4]\n" " teq %1, %2\n" @@ -103,6 +117,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, : "+r" (ret), "=&r" (val) : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) : "cc", "memory"); + uaccess_restore(__ua_flags); *uval = val; preempt_enable(); diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 74b17d09ef7a..82880132f941 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -49,6 +49,21 @@ struct exception_table_entry extern int fixup_exception(struct pt_regs *regs); +/* + * These two functions allow hooking accesses to userspace to increase + * system integrity by ensuring that the kernel can not inadvertantly + * perform such accesses (eg, via list poison values) which could then + * be exploited for priviledge escalation. + */ +static inline unsigned int uaccess_save_and_enable(void) +{ + return 0; +} + +static inline void uaccess_restore(unsigned int flags) +{ +} + /* * These two are intentionally not defined anywhere - if the kernel * code generates any references to them, that's a bug. @@ -165,6 +180,7 @@ extern int __get_user_64t_4(void *); register typeof(x) __r2 asm("r2"); \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ + unsigned int __ua_flags = uaccess_save_and_enable(); \ switch (sizeof(*(__p))) { \ case 1: \ if (sizeof((x)) >= 8) \ @@ -192,6 +208,7 @@ extern int __get_user_64t_4(void *); break; \ default: __e = __get_user_bad(); break; \ } \ + uaccess_restore(__ua_flags); \ x = (typeof(*(p))) __r2; \ __e; \ }) @@ -224,6 +241,7 @@ extern int __put_user_8(void *, unsigned long long); register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ + unsigned int __ua_flags = uaccess_save_and_enable(); \ switch (sizeof(*(__p))) { \ case 1: \ __put_user_x(__r2, __p, __e, __l, 1); \ @@ -239,6 +257,7 @@ extern int __put_user_8(void *, unsigned long long); break; \ default: __e = __put_user_bad(); break; \ } \ + uaccess_restore(__ua_flags); \ __e; \ }) @@ -300,14 +319,17 @@ static inline void set_fs(mm_segment_t fs) do { \ unsigned long __gu_addr = (unsigned long)(ptr); \ unsigned long __gu_val; \ + unsigned int __ua_flags; \ __chk_user_ptr(ptr); \ might_fault(); \ + __ua_flags = uaccess_save_and_enable(); \ switch (sizeof(*(ptr))) { \ case 1: __get_user_asm_byte(__gu_val, __gu_addr, err); break; \ case 2: __get_user_asm_half(__gu_val, __gu_addr, err); break; \ case 4: __get_user_asm_word(__gu_val, __gu_addr, err); break; \ default: (__gu_val) = __get_user_bad(); \ } \ + uaccess_restore(__ua_flags); \ (x) = (__typeof__(*(ptr)))__gu_val; \ } while (0) @@ -381,9 +403,11 @@ do { \ #define __put_user_err(x, ptr, err) \ do { \ unsigned long __pu_addr = (unsigned long)(ptr); \ + unsigned int __ua_flags; \ __typeof__(*(ptr)) __pu_val = (x); \ __chk_user_ptr(ptr); \ might_fault(); \ + __ua_flags = uaccess_save_and_enable(); \ switch (sizeof(*(ptr))) { \ case 1: __put_user_asm_byte(__pu_val, __pu_addr, err); break; \ case 2: __put_user_asm_half(__pu_val, __pu_addr, err); break; \ @@ -391,6 +415,7 @@ do { \ case 8: __put_user_asm_dword(__pu_val, __pu_addr, err); break; \ default: __put_user_bad(); \ } \ + uaccess_restore(__ua_flags); \ } while (0) #define __put_user_asm_byte(x, __pu_addr, err) \ @@ -474,11 +499,46 @@ do { \ #ifdef CONFIG_MMU -extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); -extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); -extern unsigned long __must_check __copy_to_user_std(void __user *to, const void *from, unsigned long n); -extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); -extern unsigned long __must_check __clear_user_std(void __user *addr, unsigned long n); +extern unsigned long __must_check +arm_copy_from_user(void *to, const void __user *from, unsigned long n); + +static inline unsigned long __must_check +__copy_from_user(void *to, const void __user *from, unsigned long n) +{ + unsigned int __ua_flags = uaccess_save_and_enable(); + n = arm_copy_from_user(to, from, n); + uaccess_restore(__ua_flags); + return n; +} + +extern unsigned long __must_check +arm_copy_to_user(void __user *to, const void *from, unsigned long n); +extern unsigned long __must_check +__copy_to_user_std(void __user *to, const void *from, unsigned long n); + +static inline unsigned long __must_check +__copy_to_user(void __user *to, const void *from, unsigned long n) +{ + unsigned int __ua_flags = uaccess_save_and_enable(); + n = arm_copy_to_user(to, from, n); + uaccess_restore(__ua_flags); + return n; +} + +extern unsigned long __must_check +arm_clear_user(void __user *addr, unsigned long n); +extern unsigned long __must_check +__clear_user_std(void __user *addr, unsigned long n); + +static inline unsigned long __must_check +__clear_user(void __user *addr, unsigned long n) +{ + unsigned int __ua_flags = uaccess_save_and_enable(); + n = arm_clear_user(addr, n); + uaccess_restore(__ua_flags); + return n; +} + #else #define __copy_from_user(to, from, n) (memcpy(to, (void __force *)from, n), 0) #define __copy_to_user(to, from, n) (memcpy((void __force *)to, from, n), 0) @@ -511,6 +571,7 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo return n; } +/* These are from lib/ code, and use __get_user() and friends */ extern long strncpy_from_user(char *dest, const char __user *src, long count); extern __must_check long strlen_user(const char __user *str); diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c index a88671cfe1ff..a35d72d30b56 100644 --- a/arch/arm/kernel/armksyms.c +++ b/arch/arm/kernel/armksyms.c @@ -91,9 +91,9 @@ EXPORT_SYMBOL(__memzero); #ifdef CONFIG_MMU EXPORT_SYMBOL(copy_page); -EXPORT_SYMBOL(__copy_from_user); -EXPORT_SYMBOL(__copy_to_user); -EXPORT_SYMBOL(__clear_user); +EXPORT_SYMBOL(arm_copy_from_user); +EXPORT_SYMBOL(arm_copy_to_user); +EXPORT_SYMBOL(arm_clear_user); EXPORT_SYMBOL(__get_user_1); EXPORT_SYMBOL(__get_user_2); diff --git a/arch/arm/lib/clear_user.S b/arch/arm/lib/clear_user.S index 1710fd7db2d5..970d6c043774 100644 --- a/arch/arm/lib/clear_user.S +++ b/arch/arm/lib/clear_user.S @@ -12,14 +12,14 @@ .text -/* Prototype: int __clear_user(void *addr, size_t sz) +/* Prototype: unsigned long arm_clear_user(void *addr, size_t sz) * Purpose : clear some user memory * Params : addr - user memory address to clear * : sz - number of bytes to clear * Returns : number of bytes NOT cleared */ ENTRY(__clear_user_std) -WEAK(__clear_user) +WEAK(arm_clear_user) stmfd sp!, {r1, lr} mov r2, #0 cmp r1, #4 @@ -44,7 +44,7 @@ WEAK(__clear_user) USER( strnebt r2, [r0]) mov r0, #0 ldmfd sp!, {r1, pc} -ENDPROC(__clear_user) +ENDPROC(arm_clear_user) ENDPROC(__clear_user_std) .pushsection .text.fixup,"ax" diff --git a/arch/arm/lib/copy_from_user.S b/arch/arm/lib/copy_from_user.S index 7a235b9952be..1512bebfbf1b 100644 --- a/arch/arm/lib/copy_from_user.S +++ b/arch/arm/lib/copy_from_user.S @@ -17,7 +17,7 @@ /* * Prototype: * - * size_t __copy_from_user(void *to, const void *from, size_t n) + * size_t arm_copy_from_user(void *to, const void *from, size_t n) * * Purpose: * @@ -89,11 +89,11 @@ .text -ENTRY(__copy_from_user) +ENTRY(arm_copy_from_user) #include "copy_template.S" -ENDPROC(__copy_from_user) +ENDPROC(arm_copy_from_user) .pushsection .fixup,"ax" .align 0 diff --git a/arch/arm/lib/copy_to_user.S b/arch/arm/lib/copy_to_user.S index 9648b0675a3e..caf5019d8161 100644 --- a/arch/arm/lib/copy_to_user.S +++ b/arch/arm/lib/copy_to_user.S @@ -17,7 +17,7 @@ /* * Prototype: * - * size_t __copy_to_user(void *to, const void *from, size_t n) + * size_t arm_copy_to_user(void *to, const void *from, size_t n) * * Purpose: * @@ -93,11 +93,11 @@ .text ENTRY(__copy_to_user_std) -WEAK(__copy_to_user) +WEAK(arm_copy_to_user) #include "copy_template.S" -ENDPROC(__copy_to_user) +ENDPROC(arm_copy_to_user) ENDPROC(__copy_to_user_std) .pushsection .text.fixup,"ax" diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c index 3e58d710013c..77f020e75ccd 100644 --- a/arch/arm/lib/uaccess_with_memcpy.c +++ b/arch/arm/lib/uaccess_with_memcpy.c @@ -136,7 +136,7 @@ out: } unsigned long -__copy_to_user(void __user *to, const void *from, unsigned long n) +arm_copy_to_user(void __user *to, const void *from, unsigned long n) { /* * This test is stubbed out of the main function above to keep @@ -190,7 +190,7 @@ out: return n; } -unsigned long __clear_user(void __user *addr, unsigned long n) +unsigned long arm_clear_user(void __user *addr, unsigned long n) { /* See rational for this in __copy_to_user() above. */ if (n < 64) -- cgit v1.2.3 From a5e090acbf545c0a3b04080f8a488b17ec41fe02 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 19 Aug 2015 20:40:41 +0100 Subject: ARM: software-based priviledged-no-access support Provide a software-based implementation of the priviledged no access support found in ARMv8.1. Userspace pages are mapped using a different domain number from the kernel and IO mappings. If we switch the user domain to "no access" when we enter the kernel, we can prevent the kernel from touching userspace. However, the kernel needs to be able to access userspace via the various user accessor functions. With the wrapping in the previous patch, we can temporarily enable access when the kernel needs user access, and re-disable it afterwards. This allows us to trap non-intended accesses to userspace, eg, caused by an inadvertent dereference of the LIST_POISON* values, which, with appropriate user mappings setup, can be made to succeed. This in turn can allow use-after-free bugs to be further exploited than would otherwise be possible. Signed-off-by: Russell King --- arch/arm/Kconfig | 15 +++++++++++++++ arch/arm/include/asm/assembler.h | 30 ++++++++++++++++++++++++++++++ arch/arm/include/asm/domain.h | 21 +++++++++++++++++++-- arch/arm/include/asm/uaccess.h | 14 ++++++++++++++ arch/arm/kernel/process.c | 36 ++++++++++++++++++++++++++++++------ arch/arm/kernel/swp_emulate.c | 3 +++ arch/arm/lib/csumpartialcopyuser.S | 14 ++++++++++++++ 7 files changed, 125 insertions(+), 8 deletions(-) (limited to 'arch/arm/lib') diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index a750c1425c3a..e15d5ed4d5f1 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1694,6 +1694,21 @@ config HIGHPTE bool "Allocate 2nd-level pagetables from highmem" depends on HIGHMEM +config CPU_SW_DOMAIN_PAN + bool "Enable use of CPU domains to implement privileged no-access" + depends on MMU && !ARM_LPAE + default y + help + Increase kernel security by ensuring that normal kernel accesses + are unable to access userspace addresses. This can help prevent + use-after-free bugs becoming an exploitable privilege escalation + by ensuring that magic values (such as LIST_POISON) will always + fault when dereferenced. + + CPUs with low-vector mappings use a best-efforts implementation. + Their lower 1MB needs to remain accessible for the vectors, but + the remainder of userspace will become appropriately inaccessible. + config HW_PERF_EVENTS bool "Enable hardware performance counter support for perf events" depends on PERF_EVENTS diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index a91177043467..3ae0eda5e64f 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -446,15 +446,45 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) .endm .macro uaccess_disable, tmp, isb=1 +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Whenever we re-enter userspace, the domains should always be + * set appropriately. + */ + mov \tmp, #DACR_UACCESS_DISABLE + mcr p15, 0, \tmp, c3, c0, 0 @ Set domain register + .if \isb + instr_sync + .endif +#endif .endm .macro uaccess_enable, tmp, isb=1 +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Whenever we re-enter userspace, the domains should always be + * set appropriately. + */ + mov \tmp, #DACR_UACCESS_ENABLE + mcr p15, 0, \tmp, c3, c0, 0 + .if \isb + instr_sync + .endif +#endif .endm .macro uaccess_save, tmp +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + mrc p15, 0, \tmp, c3, c0, 0 + str \tmp, [sp, #S_FRAME_SIZE] +#endif .endm .macro uaccess_restore +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + ldr r0, [sp, #S_FRAME_SIZE] + mcr p15, 0, r0, c3, c0, 0 +#endif .endm .macro uaccess_save_and_disable, tmp diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h index 2be929549938..e878129f2fee 100644 --- a/arch/arm/include/asm/domain.h +++ b/arch/arm/include/asm/domain.h @@ -57,11 +57,29 @@ #define domain_mask(dom) ((3) << (2 * (dom))) #define domain_val(dom,type) ((type) << (2 * (dom))) +#ifdef CONFIG_CPU_SW_DOMAIN_PAN +#define DACR_INIT \ + (domain_val(DOMAIN_USER, DOMAIN_NOACCESS) | \ + domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \ + domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \ + domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT)) +#else #define DACR_INIT \ (domain_val(DOMAIN_USER, DOMAIN_CLIENT) | \ domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \ domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \ domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT)) +#endif + +#define __DACR_DEFAULT \ + domain_val(DOMAIN_KERNEL, DOMAIN_CLIENT) | \ + domain_val(DOMAIN_IO, DOMAIN_CLIENT) | \ + domain_val(DOMAIN_VECTORS, DOMAIN_CLIENT) + +#define DACR_UACCESS_DISABLE \ + (__DACR_DEFAULT | domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) +#define DACR_UACCESS_ENABLE \ + (__DACR_DEFAULT | domain_val(DOMAIN_USER, DOMAIN_CLIENT)) #ifndef __ASSEMBLY__ @@ -76,7 +94,6 @@ static inline unsigned int get_domain(void) return domain; } -#ifdef CONFIG_CPU_USE_DOMAINS static inline void set_domain(unsigned val) { asm volatile( @@ -85,6 +102,7 @@ static inline void set_domain(unsigned val) isb(); } +#ifdef CONFIG_CPU_USE_DOMAINS #define modify_domain(dom,type) \ do { \ unsigned int domain = get_domain(); \ @@ -94,7 +112,6 @@ static inline void set_domain(unsigned val) } while (0) #else -static inline void set_domain(unsigned val) { } static inline void modify_domain(unsigned dom, unsigned type) { } #endif diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 82880132f941..01bae13b2cea 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -57,11 +57,25 @@ extern int fixup_exception(struct pt_regs *regs); */ static inline unsigned int uaccess_save_and_enable(void) { +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + unsigned int old_domain = get_domain(); + + /* Set the current domain access to permit user accesses */ + set_domain((old_domain & ~domain_mask(DOMAIN_USER)) | + domain_val(DOMAIN_USER, DOMAIN_CLIENT)); + + return old_domain; +#else return 0; +#endif } static inline void uaccess_restore(unsigned int flags) { +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* Restore the user access mask */ + set_domain(flags); +#endif } /* diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index e722f9b3c9b1..3f18098dfd08 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -129,12 +129,36 @@ void __show_regs(struct pt_regs *regs) buf[4] = '\0'; #ifndef CONFIG_CPU_V7M - printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", - buf, interrupts_enabled(regs) ? "n" : "ff", - fast_interrupts_enabled(regs) ? "n" : "ff", - processor_modes[processor_mode(regs)], - isa_modes[isa_mode(regs)], - get_fs() == get_ds() ? "kernel" : "user"); + { + unsigned int domain = get_domain(); + const char *segment; + +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Get the domain register for the parent context. In user + * mode, we don't save the DACR, so lets use what it should + * be. For other modes, we place it after the pt_regs struct. + */ + if (user_mode(regs)) + domain = DACR_UACCESS_ENABLE; + else + domain = *(unsigned int *)(regs + 1); +#endif + + if ((domain & domain_mask(DOMAIN_USER)) == + domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) + segment = "none"; + else if (get_fs() == get_ds()) + segment = "kernel"; + else + segment = "user"; + + printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", + buf, interrupts_enabled(regs) ? "n" : "ff", + fast_interrupts_enabled(regs) ? "n" : "ff", + processor_modes[processor_mode(regs)], + isa_modes[isa_mode(regs)], segment); + } #else printk("xPSR: %08lx\n", regs->ARM_cpsr); #endif diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c index 1361756782c7..5b26e7efa9ea 100644 --- a/arch/arm/kernel/swp_emulate.c +++ b/arch/arm/kernel/swp_emulate.c @@ -141,11 +141,14 @@ static int emulate_swpX(unsigned int address, unsigned int *data, while (1) { unsigned long temp; + unsigned int __ua_flags; + __ua_flags = uaccess_save_and_enable(); if (type == TYPE_SWPB) __user_swpb_asm(*data, address, res, temp); else __user_swp_asm(*data, address, res, temp); + uaccess_restore(__ua_flags); if (likely(res != -EAGAIN) || signal_pending(current)) break; diff --git a/arch/arm/lib/csumpartialcopyuser.S b/arch/arm/lib/csumpartialcopyuser.S index 1d0957e61f89..1712f132b80d 100644 --- a/arch/arm/lib/csumpartialcopyuser.S +++ b/arch/arm/lib/csumpartialcopyuser.S @@ -17,6 +17,19 @@ .text +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + .macro save_regs + mrc p15, 0, ip, c3, c0, 0 + stmfd sp!, {r1, r2, r4 - r8, ip, lr} + uaccess_enable ip + .endm + + .macro load_regs + ldmfd sp!, {r1, r2, r4 - r8, ip, lr} + mcr p15, 0, ip, c3, c0, 0 + ret lr + .endm +#else .macro save_regs stmfd sp!, {r1, r2, r4 - r8, lr} .endm @@ -24,6 +37,7 @@ .macro load_regs ldmfd sp!, {r1, r2, r4 - r8, pc} .endm +#endif .macro load1b, reg1 ldrusr \reg1, r0, 1 -- cgit v1.2.3