From a980c0ef9f6d8c45445d6ed0f5836bb6941c8c91 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 Aug 2018 22:14:15 +0200 Subject: x86/kprobes: Refactor kprobes_fault() like kprobe_exceptions_notify() This is an extension of commit b506a9d08bae ("x86: code clarification patch to Kprobes arch code"). As that commit explains, even though kprobe_running() can't be called with preemption enabled, preemption does not need to be disabled. If preemption is enabled, then this can't be originate from a kprobe. Also, use X86_TRAP_PF instead of 14. Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Acked-by: Masami Hiramatsu Cc: Andy Lutomirski Cc: kernel-hardening@lists.openwall.com Cc: dvyukov@google.com Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-2-jannh@google.com --- arch/x86/mm/fault.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) (limited to 'arch') diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 47bebfe6efa7..d99edb2d567b 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -44,17 +44,19 @@ kmmio_fault(struct pt_regs *regs, unsigned long addr) static nokprobe_inline int kprobes_fault(struct pt_regs *regs) { - int ret = 0; - - /* kprobe_running() needs smp_processor_id() */ - if (kprobes_built_in() && !user_mode(regs)) { - preempt_disable(); - if (kprobe_running() && kprobe_fault_handler(regs, 14)) - ret = 1; - preempt_enable(); - } - - return ret; + if (!kprobes_built_in()) + return 0; + if (user_mode(regs)) + return 0; + /* + * To be potentially processing a kprobe fault and to be allowed to call + * kprobe_running(), we have to be non-preemptible. + */ + if (preemptible()) + return 0; + if (!kprobe_running()) + return 0; + return kprobe_fault_handler(regs, X86_TRAP_PF); } /* -- cgit v1.2.3 From 76dee4a72849561f6ffacc357cfd0aa33336081a Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 Aug 2018 22:14:16 +0200 Subject: x86/kprobes: Inline kprobe_exceptions_notify() into do_general_protection() The opaque plumbing of #GP from do_general_protection() through notify_die() into kprobe_exceptions_notify() makes it hard to understand what's going on. Suggested-by: Andy Lutomirski Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Acked-by: Masami Hiramatsu Cc: kernel-hardening@lists.openwall.com Cc: dvyukov@google.com Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-3-jannh@google.com --- arch/x86/kernel/kprobes/core.c | 31 +------------------------------ arch/x86/kernel/traps.c | 10 ++++++++++ 2 files changed, 11 insertions(+), 30 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index b0d1e81c96bb..467ac22691b0 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1028,42 +1028,13 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) if (fixup_exception(regs, trapnr)) return 1; - /* - * fixup routine could not handle it, - * Let do_page_fault() fix it. - */ + /* fixup routine could not handle it. */ } return 0; } NOKPROBE_SYMBOL(kprobe_fault_handler); -/* - * Wrapper routine for handling exceptions. - */ -int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, - void *data) -{ - struct die_args *args = data; - int ret = NOTIFY_DONE; - - if (args->regs && user_mode(args->regs)) - return ret; - - if (val == DIE_GPF) { - /* - * To be potentially processing a kprobe fault and to - * trust the result from kprobe_running(), we have - * be non-preemptible. - */ - if (!preemptible() && kprobe_running() && - kprobe_fault_handler(args->regs, args->trapnr)) - ret = NOTIFY_STOP; - } - return ret; -} -NOKPROBE_SYMBOL(kprobe_exceptions_notify); - bool arch_within_kprobe_blacklist(unsigned long addr) { bool is_in_entry_trampoline_section = false; diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index e6db475164ed..bf9ab1aaa175 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -556,6 +556,16 @@ do_general_protection(struct pt_regs *regs, long error_code) tsk->thread.error_code = error_code; tsk->thread.trap_nr = X86_TRAP_GP; + + /* + * To be potentially processing a kprobe fault and to + * trust the result from kprobe_running(), we have to + * be non-preemptible. + */ + if (!preemptible() && kprobe_running() && + kprobe_fault_handler(regs, X86_TRAP_GP)) + return; + if (notify_die(DIE_GPF, "general protection fault", regs, error_code, X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP) die("general protection fault", regs, error_code); -- cgit v1.2.3 From e3e4d5019c2dd0f91600f6df377b215a73d506fe Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 Aug 2018 22:14:17 +0200 Subject: x86/kprobes: Stop calling fixup_exception() from kprobe_fault_handler() This removes the call into exception fixup that was added in commit c28f896634f2 ("[PATCH] kprobes: fix broken fault handling for x86_64"). On X86, kprobe_fault_handler() is called from two places: do_general_protection() (for #GP) and kprobes_fault() (for #PF). In both paths, the fixup_exception() call in the kprobe fault handler is redundant. In case of #GP, fixup_exception() is called immediately before kprobe_fault_handler() is invoked, so no need to try that again. This assumes that the kprobe's fault handler isn't going to do something crazy like changing RIP so that it suddenly points to an instruction that does userspace access. For #PF on a kernel address from kernel space, after the kprobe fault handler has run, no_context() is invoked, which calls fixup_exception(). Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Acked-by: Masami Hiramatsu Cc: Andy Lutomirski Cc: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org Cc: dvyukov@google.com Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-4-jannh@google.com --- arch/x86/kernel/kprobes/core.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 467ac22691b0..f72a47b602e2 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1020,15 +1020,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) */ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) return 1; - - /* - * In case the user-specified fault handler returned - * zero, try to fix up. - */ - if (fixup_exception(regs, trapnr)) - return 1; - - /* fixup routine could not handle it. */ } return 0; -- cgit v1.2.3 From 75045f77f7a73e617494d7a1fcf4e9c1849cec39 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 Aug 2018 22:14:18 +0200 Subject: x86/extable: Introduce _ASM_EXTABLE_UA for uaccess fixups Currently, most fixups for attempting to access userspace memory are handled using _ASM_EXTABLE, which is also used for various other types of fixups (e.g. safe MSR access, IRET failures, and a bunch of other things). In order to make it possible to add special safety checks to uaccess fixups (in particular, checking whether the fault address is actually in userspace), introduce a new exception table handler ex_handler_uaccess() and wire it up to all the user access fixups (excluding ones that already use _ASM_EXTABLE_EX). Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Cc: Andy Lutomirski Cc: kernel-hardening@lists.openwall.com Cc: dvyukov@google.com Cc: Masami Hiramatsu Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-5-jannh@google.com --- arch/x86/include/asm/asm.h | 10 ++- arch/x86/include/asm/fpu/internal.h | 2 +- arch/x86/include/asm/futex.h | 6 +- arch/x86/include/asm/uaccess.h | 22 +++---- arch/x86/lib/checksum_32.S | 4 +- arch/x86/lib/copy_user_64.S | 90 +++++++++++++------------- arch/x86/lib/csum-copy_64.S | 8 ++- arch/x86/lib/getuser.S | 12 ++-- arch/x86/lib/putuser.S | 10 +-- arch/x86/lib/usercopy_32.c | 126 ++++++++++++++++++------------------ arch/x86/lib/usercopy_64.c | 4 +- arch/x86/mm/extable.c | 8 +++ 12 files changed, 160 insertions(+), 142 deletions(-) (limited to 'arch') diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 990770f9e76b..6467757bb39f 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -130,6 +130,9 @@ # define _ASM_EXTABLE(from, to) \ _ASM_EXTABLE_HANDLE(from, to, ex_handler_default) +# define _ASM_EXTABLE_UA(from, to) \ + _ASM_EXTABLE_HANDLE(from, to, ex_handler_uaccess) + # define _ASM_EXTABLE_FAULT(from, to) \ _ASM_EXTABLE_HANDLE(from, to, ex_handler_fault) @@ -165,8 +168,8 @@ jmp copy_user_handle_tail .previous - _ASM_EXTABLE(100b,103b) - _ASM_EXTABLE(101b,103b) + _ASM_EXTABLE_UA(100b, 103b) + _ASM_EXTABLE_UA(101b, 103b) .endm #else @@ -182,6 +185,9 @@ # define _ASM_EXTABLE(from, to) \ _ASM_EXTABLE_HANDLE(from, to, ex_handler_default) +# define _ASM_EXTABLE_UA(from, to) \ + _ASM_EXTABLE_HANDLE(from, to, ex_handler_uaccess) + # define _ASM_EXTABLE_FAULT(from, to) \ _ASM_EXTABLE_HANDLE(from, to, ex_handler_fault) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index a38bf5a1e37a..068ff7689268 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -226,7 +226,7 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu) "3: movl $-2,%[err]\n\t" \ "jmp 2b\n\t" \ ".popsection\n\t" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : [err] "=r" (err) \ : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ : "memory") diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h index de4d68852d3a..13c83fe97988 100644 --- a/arch/x86/include/asm/futex.h +++ b/arch/x86/include/asm/futex.h @@ -20,7 +20,7 @@ "3:\tmov\t%3, %1\n" \ "\tjmp\t2b\n" \ "\t.previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \ : "i" (-EFAULT), "0" (oparg), "1" (0)) @@ -36,8 +36,8 @@ "4:\tmov\t%5, %1\n" \ "\tjmp\t3b\n" \ "\t.previous\n" \ - _ASM_EXTABLE(1b, 4b) \ - _ASM_EXTABLE(2b, 4b) \ + _ASM_EXTABLE_UA(1b, 4b) \ + _ASM_EXTABLE_UA(2b, 4b) \ : "=&a" (oldval), "=&r" (ret), \ "+m" (*uaddr), "=&r" (tem) \ : "r" (oparg), "i" (-EFAULT), "1" (0)) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index aae77eb8491c..b5e58cc0c5e7 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -198,8 +198,8 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) "4: movl %3,%0\n" \ " jmp 3b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b, 4b) \ - _ASM_EXTABLE(2b, 4b) \ + _ASM_EXTABLE_UA(1b, 4b) \ + _ASM_EXTABLE_UA(2b, 4b) \ : "=r" (err) \ : "A" (x), "r" (addr), "i" (errret), "0" (err)) @@ -340,8 +340,8 @@ do { \ " xorl %%edx,%%edx\n" \ " jmp 3b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b, 4b) \ - _ASM_EXTABLE(2b, 4b) \ + _ASM_EXTABLE_UA(1b, 4b) \ + _ASM_EXTABLE_UA(2b, 4b) \ : "=r" (retval), "=&A"(x) \ : "m" (__m(__ptr)), "m" __m(((u32 __user *)(__ptr)) + 1), \ "i" (errret), "0" (retval)); \ @@ -386,7 +386,7 @@ do { \ " xor"itype" %"rtype"1,%"rtype"1\n" \ " jmp 2b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "=r" (err), ltype(x) \ : "m" (__m(addr)), "i" (errret), "0" (err)) @@ -398,7 +398,7 @@ do { \ "3: mov %3,%0\n" \ " jmp 2b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "=r" (err), ltype(x) \ : "m" (__m(addr)), "i" (errret), "0" (err)) @@ -474,7 +474,7 @@ struct __large_struct { unsigned long buf[100]; }; "3: mov %3,%0\n" \ " jmp 2b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "=r"(err) \ : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) @@ -602,7 +602,7 @@ extern void __cmpxchg_wrong_size(void) "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ : "i" (-EFAULT), "q" (__new), "1" (__old) \ : "memory" \ @@ -618,7 +618,7 @@ extern void __cmpxchg_wrong_size(void) "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ : "i" (-EFAULT), "r" (__new), "1" (__old) \ : "memory" \ @@ -634,7 +634,7 @@ extern void __cmpxchg_wrong_size(void) "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ : "i" (-EFAULT), "r" (__new), "1" (__old) \ : "memory" \ @@ -653,7 +653,7 @@ extern void __cmpxchg_wrong_size(void) "3:\tmov %3, %0\n" \ "\tjmp 2b\n" \ "\t.previous\n" \ - _ASM_EXTABLE(1b, 3b) \ + _ASM_EXTABLE_UA(1b, 3b) \ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ : "i" (-EFAULT), "r" (__new), "1" (__old) \ : "memory" \ diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S index 46e71a74e612..ad8e0906d1ea 100644 --- a/arch/x86/lib/checksum_32.S +++ b/arch/x86/lib/checksum_32.S @@ -273,11 +273,11 @@ unsigned int csum_partial_copy_generic (const char *src, char *dst, #define SRC(y...) \ 9999: y; \ - _ASM_EXTABLE(9999b, 6001f) + _ASM_EXTABLE_UA(9999b, 6001f) #define DST(y...) \ 9999: y; \ - _ASM_EXTABLE(9999b, 6002f) + _ASM_EXTABLE_UA(9999b, 6002f) #ifndef CONFIG_X86_USE_PPRO_CHECKSUM diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S index 020f75cc8cf6..db4e5aa0858b 100644 --- a/arch/x86/lib/copy_user_64.S +++ b/arch/x86/lib/copy_user_64.S @@ -92,26 +92,26 @@ ENTRY(copy_user_generic_unrolled) 60: jmp copy_user_handle_tail /* ecx is zerorest also */ .previous - _ASM_EXTABLE(1b,30b) - _ASM_EXTABLE(2b,30b) - _ASM_EXTABLE(3b,30b) - _ASM_EXTABLE(4b,30b) - _ASM_EXTABLE(5b,30b) - _ASM_EXTABLE(6b,30b) - _ASM_EXTABLE(7b,30b) - _ASM_EXTABLE(8b,30b) - _ASM_EXTABLE(9b,30b) - _ASM_EXTABLE(10b,30b) - _ASM_EXTABLE(11b,30b) - _ASM_EXTABLE(12b,30b) - _ASM_EXTABLE(13b,30b) - _ASM_EXTABLE(14b,30b) - _ASM_EXTABLE(15b,30b) - _ASM_EXTABLE(16b,30b) - _ASM_EXTABLE(18b,40b) - _ASM_EXTABLE(19b,40b) - _ASM_EXTABLE(21b,50b) - _ASM_EXTABLE(22b,50b) + _ASM_EXTABLE_UA(1b, 30b) + _ASM_EXTABLE_UA(2b, 30b) + _ASM_EXTABLE_UA(3b, 30b) + _ASM_EXTABLE_UA(4b, 30b) + _ASM_EXTABLE_UA(5b, 30b) + _ASM_EXTABLE_UA(6b, 30b) + _ASM_EXTABLE_UA(7b, 30b) + _ASM_EXTABLE_UA(8b, 30b) + _ASM_EXTABLE_UA(9b, 30b) + _ASM_EXTABLE_UA(10b, 30b) + _ASM_EXTABLE_UA(11b, 30b) + _ASM_EXTABLE_UA(12b, 30b) + _ASM_EXTABLE_UA(13b, 30b) + _ASM_EXTABLE_UA(14b, 30b) + _ASM_EXTABLE_UA(15b, 30b) + _ASM_EXTABLE_UA(16b, 30b) + _ASM_EXTABLE_UA(18b, 40b) + _ASM_EXTABLE_UA(19b, 40b) + _ASM_EXTABLE_UA(21b, 50b) + _ASM_EXTABLE_UA(22b, 50b) ENDPROC(copy_user_generic_unrolled) EXPORT_SYMBOL(copy_user_generic_unrolled) @@ -156,8 +156,8 @@ ENTRY(copy_user_generic_string) jmp copy_user_handle_tail .previous - _ASM_EXTABLE(1b,11b) - _ASM_EXTABLE(3b,12b) + _ASM_EXTABLE_UA(1b, 11b) + _ASM_EXTABLE_UA(3b, 12b) ENDPROC(copy_user_generic_string) EXPORT_SYMBOL(copy_user_generic_string) @@ -189,7 +189,7 @@ ENTRY(copy_user_enhanced_fast_string) jmp copy_user_handle_tail .previous - _ASM_EXTABLE(1b,12b) + _ASM_EXTABLE_UA(1b, 12b) ENDPROC(copy_user_enhanced_fast_string) EXPORT_SYMBOL(copy_user_enhanced_fast_string) @@ -319,27 +319,27 @@ ENTRY(__copy_user_nocache) jmp copy_user_handle_tail .previous - _ASM_EXTABLE(1b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(2b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(3b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(4b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(5b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(6b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(7b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(8b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(9b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(10b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(11b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(12b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(13b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(14b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(15b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(16b,.L_fixup_4x8b_copy) - _ASM_EXTABLE(20b,.L_fixup_8b_copy) - _ASM_EXTABLE(21b,.L_fixup_8b_copy) - _ASM_EXTABLE(30b,.L_fixup_4b_copy) - _ASM_EXTABLE(31b,.L_fixup_4b_copy) - _ASM_EXTABLE(40b,.L_fixup_1b_copy) - _ASM_EXTABLE(41b,.L_fixup_1b_copy) + _ASM_EXTABLE_UA(1b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(2b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(3b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(4b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(5b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(6b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(7b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(8b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(9b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(10b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(11b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(12b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(13b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(14b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(15b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(16b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_UA(20b, .L_fixup_8b_copy) + _ASM_EXTABLE_UA(21b, .L_fixup_8b_copy) + _ASM_EXTABLE_UA(30b, .L_fixup_4b_copy) + _ASM_EXTABLE_UA(31b, .L_fixup_4b_copy) + _ASM_EXTABLE_UA(40b, .L_fixup_1b_copy) + _ASM_EXTABLE_UA(41b, .L_fixup_1b_copy) ENDPROC(__copy_user_nocache) EXPORT_SYMBOL(__copy_user_nocache) diff --git a/arch/x86/lib/csum-copy_64.S b/arch/x86/lib/csum-copy_64.S index 45a53dfe1859..a4a379e79259 100644 --- a/arch/x86/lib/csum-copy_64.S +++ b/arch/x86/lib/csum-copy_64.S @@ -31,14 +31,18 @@ .macro source 10: - _ASM_EXTABLE(10b, .Lbad_source) + _ASM_EXTABLE_UA(10b, .Lbad_source) .endm .macro dest 20: - _ASM_EXTABLE(20b, .Lbad_dest) + _ASM_EXTABLE_UA(20b, .Lbad_dest) .endm + /* + * No _ASM_EXTABLE_UA; this is used for intentional prefetch on a + * potentially unmapped kernel address. + */ .macro ignore L=.Lignore 30: _ASM_EXTABLE(30b, \L) diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 49b167f73215..74fdff968ea3 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -132,12 +132,12 @@ bad_get_user_8: END(bad_get_user_8) #endif - _ASM_EXTABLE(1b,bad_get_user) - _ASM_EXTABLE(2b,bad_get_user) - _ASM_EXTABLE(3b,bad_get_user) + _ASM_EXTABLE_UA(1b, bad_get_user) + _ASM_EXTABLE_UA(2b, bad_get_user) + _ASM_EXTABLE_UA(3b, bad_get_user) #ifdef CONFIG_X86_64 - _ASM_EXTABLE(4b,bad_get_user) + _ASM_EXTABLE_UA(4b, bad_get_user) #else - _ASM_EXTABLE(4b,bad_get_user_8) - _ASM_EXTABLE(5b,bad_get_user_8) + _ASM_EXTABLE_UA(4b, bad_get_user_8) + _ASM_EXTABLE_UA(5b, bad_get_user_8) #endif diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S index 96dce5fe2a35..d2e5c9c39601 100644 --- a/arch/x86/lib/putuser.S +++ b/arch/x86/lib/putuser.S @@ -94,10 +94,10 @@ bad_put_user: EXIT END(bad_put_user) - _ASM_EXTABLE(1b,bad_put_user) - _ASM_EXTABLE(2b,bad_put_user) - _ASM_EXTABLE(3b,bad_put_user) - _ASM_EXTABLE(4b,bad_put_user) + _ASM_EXTABLE_UA(1b, bad_put_user) + _ASM_EXTABLE_UA(2b, bad_put_user) + _ASM_EXTABLE_UA(3b, bad_put_user) + _ASM_EXTABLE_UA(4b, bad_put_user) #ifdef CONFIG_X86_32 - _ASM_EXTABLE(5b,bad_put_user) + _ASM_EXTABLE_UA(5b, bad_put_user) #endif diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c index 7add8ba06887..71fb58d44d58 100644 --- a/arch/x86/lib/usercopy_32.c +++ b/arch/x86/lib/usercopy_32.c @@ -47,8 +47,8 @@ do { \ "3: lea 0(%2,%0,4),%0\n" \ " jmp 2b\n" \ ".previous\n" \ - _ASM_EXTABLE(0b,3b) \ - _ASM_EXTABLE(1b,2b) \ + _ASM_EXTABLE_UA(0b, 3b) \ + _ASM_EXTABLE_UA(1b, 2b) \ : "=&c"(size), "=&D" (__d0) \ : "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0)); \ } while (0) @@ -153,44 +153,44 @@ __copy_user_intel(void __user *to, const void *from, unsigned long size) "101: lea 0(%%eax,%0,4),%0\n" " jmp 100b\n" ".previous\n" - _ASM_EXTABLE(1b,100b) - _ASM_EXTABLE(2b,100b) - _ASM_EXTABLE(3b,100b) - _ASM_EXTABLE(4b,100b) - _ASM_EXTABLE(5b,100b) - _ASM_EXTABLE(6b,100b) - _ASM_EXTABLE(7b,100b) - _ASM_EXTABLE(8b,100b) - _ASM_EXTABLE(9b,100b) - _ASM_EXTABLE(10b,100b) - _ASM_EXTABLE(11b,100b) - _ASM_EXTABLE(12b,100b) - _ASM_EXTABLE(13b,100b) - _ASM_EXTABLE(14b,100b) - _ASM_EXTABLE(15b,100b) - _ASM_EXTABLE(16b,100b) - _ASM_EXTABLE(17b,100b) - _ASM_EXTABLE(18b,100b) - _ASM_EXTABLE(19b,100b) - _ASM_EXTABLE(20b,100b) - _ASM_EXTABLE(21b,100b) - _ASM_EXTABLE(22b,100b) - _ASM_EXTABLE(23b,100b) - _ASM_EXTABLE(24b,100b) - _ASM_EXTABLE(25b,100b) - _ASM_EXTABLE(26b,100b) - _ASM_EXTABLE(27b,100b) - _ASM_EXTABLE(28b,100b) - _ASM_EXTABLE(29b,100b) - _ASM_EXTABLE(30b,100b) - _ASM_EXTABLE(31b,100b) - _ASM_EXTABLE(32b,100b) - _ASM_EXTABLE(33b,100b) - _ASM_EXTABLE(34b,100b) - _ASM_EXTABLE(35b,100b) - _ASM_EXTABLE(36b,100b) - _ASM_EXTABLE(37b,100b) - _ASM_EXTABLE(99b,101b) + _ASM_EXTABLE_UA(1b, 100b) + _ASM_EXTABLE_UA(2b, 100b) + _ASM_EXTABLE_UA(3b, 100b) + _ASM_EXTABLE_UA(4b, 100b) + _ASM_EXTABLE_UA(5b, 100b) + _ASM_EXTABLE_UA(6b, 100b) + _ASM_EXTABLE_UA(7b, 100b) + _ASM_EXTABLE_UA(8b, 100b) + _ASM_EXTABLE_UA(9b, 100b) + _ASM_EXTABLE_UA(10b, 100b) + _ASM_EXTABLE_UA(11b, 100b) + _ASM_EXTABLE_UA(12b, 100b) + _ASM_EXTABLE_UA(13b, 100b) + _ASM_EXTABLE_UA(14b, 100b) + _ASM_EXTABLE_UA(15b, 100b) + _ASM_EXTABLE_UA(16b, 100b) + _ASM_EXTABLE_UA(17b, 100b) + _ASM_EXTABLE_UA(18b, 100b) + _ASM_EXTABLE_UA(19b, 100b) + _ASM_EXTABLE_UA(20b, 100b) + _ASM_EXTABLE_UA(21b, 100b) + _ASM_EXTABLE_UA(22b, 100b) + _ASM_EXTABLE_UA(23b, 100b) + _ASM_EXTABLE_UA(24b, 100b) + _ASM_EXTABLE_UA(25b, 100b) + _ASM_EXTABLE_UA(26b, 100b) + _ASM_EXTABLE_UA(27b, 100b) + _ASM_EXTABLE_UA(28b, 100b) + _ASM_EXTABLE_UA(29b, 100b) + _ASM_EXTABLE_UA(30b, 100b) + _ASM_EXTABLE_UA(31b, 100b) + _ASM_EXTABLE_UA(32b, 100b) + _ASM_EXTABLE_UA(33b, 100b) + _ASM_EXTABLE_UA(34b, 100b) + _ASM_EXTABLE_UA(35b, 100b) + _ASM_EXTABLE_UA(36b, 100b) + _ASM_EXTABLE_UA(37b, 100b) + _ASM_EXTABLE_UA(99b, 101b) : "=&c"(size), "=&D" (d0), "=&S" (d1) : "1"(to), "2"(from), "0"(size) : "eax", "edx", "memory"); @@ -259,26 +259,26 @@ static unsigned long __copy_user_intel_nocache(void *to, "9: lea 0(%%eax,%0,4),%0\n" "16: jmp 8b\n" ".previous\n" - _ASM_EXTABLE(0b,16b) - _ASM_EXTABLE(1b,16b) - _ASM_EXTABLE(2b,16b) - _ASM_EXTABLE(21b,16b) - _ASM_EXTABLE(3b,16b) - _ASM_EXTABLE(31b,16b) - _ASM_EXTABLE(4b,16b) - _ASM_EXTABLE(41b,16b) - _ASM_EXTABLE(10b,16b) - _ASM_EXTABLE(51b,16b) - _ASM_EXTABLE(11b,16b) - _ASM_EXTABLE(61b,16b) - _ASM_EXTABLE(12b,16b) - _ASM_EXTABLE(71b,16b) - _ASM_EXTABLE(13b,16b) - _ASM_EXTABLE(81b,16b) - _ASM_EXTABLE(14b,16b) - _ASM_EXTABLE(91b,16b) - _ASM_EXTABLE(6b,9b) - _ASM_EXTABLE(7b,16b) + _ASM_EXTABLE_UA(0b, 16b) + _ASM_EXTABLE_UA(1b, 16b) + _ASM_EXTABLE_UA(2b, 16b) + _ASM_EXTABLE_UA(21b, 16b) + _ASM_EXTABLE_UA(3b, 16b) + _ASM_EXTABLE_UA(31b, 16b) + _ASM_EXTABLE_UA(4b, 16b) + _ASM_EXTABLE_UA(41b, 16b) + _ASM_EXTABLE_UA(10b, 16b) + _ASM_EXTABLE_UA(51b, 16b) + _ASM_EXTABLE_UA(11b, 16b) + _ASM_EXTABLE_UA(61b, 16b) + _ASM_EXTABLE_UA(12b, 16b) + _ASM_EXTABLE_UA(71b, 16b) + _ASM_EXTABLE_UA(13b, 16b) + _ASM_EXTABLE_UA(81b, 16b) + _ASM_EXTABLE_UA(14b, 16b) + _ASM_EXTABLE_UA(91b, 16b) + _ASM_EXTABLE_UA(6b, 9b) + _ASM_EXTABLE_UA(7b, 16b) : "=&c"(size), "=&D" (d0), "=&S" (d1) : "1"(to), "2"(from), "0"(size) : "eax", "edx", "memory"); @@ -321,9 +321,9 @@ do { \ "3: lea 0(%3,%0,4),%0\n" \ " jmp 2b\n" \ ".previous\n" \ - _ASM_EXTABLE(4b,5b) \ - _ASM_EXTABLE(0b,3b) \ - _ASM_EXTABLE(1b,2b) \ + _ASM_EXTABLE_UA(4b, 5b) \ + _ASM_EXTABLE_UA(0b, 3b) \ + _ASM_EXTABLE_UA(1b, 2b) \ : "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2) \ : "3"(size), "0"(size), "1"(to), "2"(from) \ : "memory"); \ diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index 9c5606d88f61..fefe64436398 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -37,8 +37,8 @@ unsigned long __clear_user(void __user *addr, unsigned long size) "3: lea 0(%[size1],%[size8],8),%[size8]\n" " jmp 2b\n" ".previous\n" - _ASM_EXTABLE(0b,3b) - _ASM_EXTABLE(1b,2b) + _ASM_EXTABLE_UA(0b, 3b) + _ASM_EXTABLE_UA(1b, 2b) : [size8] "=&c"(size), [dst] "=&D" (__d0) : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr)); clac(); diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 45f5d6cf65ae..0b8b5d889eec 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -108,6 +108,14 @@ __visible bool ex_handler_fprestore(const struct exception_table_entry *fixup, } EXPORT_SYMBOL_GPL(ex_handler_fprestore); +__visible bool ex_handler_uaccess(const struct exception_table_entry *fixup, + struct pt_regs *regs, int trapnr) +{ + regs->ip = ex_fixup_addr(fixup); + return true; +} +EXPORT_SYMBOL(ex_handler_uaccess); + __visible bool ex_handler_ext(const struct exception_table_entry *fixup, struct pt_regs *regs, int trapnr) { -- cgit v1.2.3 From 81fd9c18444ed1199b5a6f6776a395292d4256fb Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 Aug 2018 22:14:19 +0200 Subject: x86/fault: Plumb error code and fault address through to fault handlers This is preparation for looking at trap number and fault address in the handlers for uaccess errors. No functional change. Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Cc: Andy Lutomirski Cc: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org Cc: dvyukov@google.com Cc: Masami Hiramatsu Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-6-jannh@google.com --- arch/x86/include/asm/extable.h | 3 ++- arch/x86/include/asm/ptrace.h | 2 ++ arch/x86/kernel/cpu/mcheck/mce.c | 2 +- arch/x86/kernel/traps.c | 6 ++--- arch/x86/mm/extable.c | 50 ++++++++++++++++++++++++++++------------ arch/x86/mm/fault.c | 2 +- 6 files changed, 44 insertions(+), 21 deletions(-) (limited to 'arch') diff --git a/arch/x86/include/asm/extable.h b/arch/x86/include/asm/extable.h index f9c3a5d502f4..d8c2198d543b 100644 --- a/arch/x86/include/asm/extable.h +++ b/arch/x86/include/asm/extable.h @@ -29,7 +29,8 @@ struct pt_regs; (b)->handler = (tmp).handler - (delta); \ } while (0) -extern int fixup_exception(struct pt_regs *regs, int trapnr); +extern int fixup_exception(struct pt_regs *regs, int trapnr, + unsigned long error_code, unsigned long fault_addr); extern int fixup_bug(struct pt_regs *regs, int trapnr); extern bool ex_has_fault_handler(unsigned long ip); extern void early_fixup_exception(struct pt_regs *regs, int trapnr); diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 6de1fd3d0097..5e58a74bfd3a 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -37,8 +37,10 @@ struct pt_regs { unsigned short __esh; unsigned short fs; unsigned short __fsh; + /* On interrupt, gs and __gsh store the vector number. */ unsigned short gs; unsigned short __gsh; + /* On interrupt, this is the error code. */ unsigned long orig_ax; unsigned long ip; unsigned short cs; diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 953b3ce92dcc..ef8fd1f2ede0 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -1315,7 +1315,7 @@ void do_machine_check(struct pt_regs *regs, long error_code) local_irq_disable(); ist_end_non_atomic(); } else { - if (!fixup_exception(regs, X86_TRAP_MC)) + if (!fixup_exception(regs, X86_TRAP_MC, error_code, 0)) mce_panic("Failed kernel mode recovery", &m, NULL); } diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index bf9ab1aaa175..16c95cb90496 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -206,7 +206,7 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str, } if (!user_mode(regs)) { - if (fixup_exception(regs, trapnr)) + if (fixup_exception(regs, trapnr, error_code, 0)) return 0; tsk->thread.error_code = error_code; @@ -551,7 +551,7 @@ do_general_protection(struct pt_regs *regs, long error_code) tsk = current; if (!user_mode(regs)) { - if (fixup_exception(regs, X86_TRAP_GP)) + if (fixup_exception(regs, X86_TRAP_GP, error_code, 0)) return; tsk->thread.error_code = error_code; @@ -848,7 +848,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr) cond_local_irq_enable(regs); if (!user_mode(regs)) { - if (fixup_exception(regs, trapnr)) + if (fixup_exception(regs, trapnr, error_code, 0)) return; task->thread.error_code = error_code; diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 0b8b5d889eec..856fa409c536 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -8,7 +8,8 @@ #include typedef bool (*ex_handler_t)(const struct exception_table_entry *, - struct pt_regs *, int); + struct pt_regs *, int, unsigned long, + unsigned long); static inline unsigned long ex_fixup_addr(const struct exception_table_entry *x) @@ -22,7 +23,9 @@ ex_fixup_handler(const struct exception_table_entry *x) } __visible bool ex_handler_default(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { regs->ip = ex_fixup_addr(fixup); return true; @@ -30,7 +33,9 @@ __visible bool ex_handler_default(const struct exception_table_entry *fixup, EXPORT_SYMBOL(ex_handler_default); __visible bool ex_handler_fault(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { regs->ip = ex_fixup_addr(fixup); regs->ax = trapnr; @@ -43,7 +48,9 @@ EXPORT_SYMBOL_GPL(ex_handler_fault); * result of a refcount inc/dec/add/sub. */ __visible bool ex_handler_refcount(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { /* First unconditionally saturate the refcount. */ *(int *)regs->cx = INT_MIN / 2; @@ -96,7 +103,9 @@ EXPORT_SYMBOL(ex_handler_refcount); * out all the FPU registers) if we can't restore from the task's FPU state. */ __visible bool ex_handler_fprestore(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { regs->ip = ex_fixup_addr(fixup); @@ -109,7 +118,9 @@ __visible bool ex_handler_fprestore(const struct exception_table_entry *fixup, EXPORT_SYMBOL_GPL(ex_handler_fprestore); __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { regs->ip = ex_fixup_addr(fixup); return true; @@ -117,7 +128,9 @@ __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup, EXPORT_SYMBOL(ex_handler_uaccess); __visible bool ex_handler_ext(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { /* Special hack for uaccess_err */ current->thread.uaccess_err = 1; @@ -127,7 +140,9 @@ __visible bool ex_handler_ext(const struct exception_table_entry *fixup, EXPORT_SYMBOL(ex_handler_ext); __visible bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pF)\n", (unsigned int)regs->cx, regs->ip, (void *)regs->ip)) @@ -142,7 +157,9 @@ __visible bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup EXPORT_SYMBOL(ex_handler_rdmsr_unsafe); __visible bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pF)\n", (unsigned int)regs->cx, (unsigned int)regs->dx, @@ -156,12 +173,14 @@ __visible bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup EXPORT_SYMBOL(ex_handler_wrmsr_unsafe); __visible bool ex_handler_clear_fs(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr) + struct pt_regs *regs, int trapnr, + unsigned long error_code, + unsigned long fault_addr) { if (static_cpu_has(X86_BUG_NULL_SEG)) asm volatile ("mov %0, %%fs" : : "rm" (__USER_DS)); asm volatile ("mov %0, %%fs" : : "rm" (0)); - return ex_handler_default(fixup, regs, trapnr); + return ex_handler_default(fixup, regs, trapnr, error_code, fault_addr); } EXPORT_SYMBOL(ex_handler_clear_fs); @@ -178,7 +197,8 @@ __visible bool ex_has_fault_handler(unsigned long ip) return handler == ex_handler_fault; } -int fixup_exception(struct pt_regs *regs, int trapnr) +int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, + unsigned long fault_addr) { const struct exception_table_entry *e; ex_handler_t handler; @@ -202,7 +222,7 @@ int fixup_exception(struct pt_regs *regs, int trapnr) return 0; handler = ex_fixup_handler(e); - return handler(e, regs, trapnr); + return handler(e, regs, trapnr, error_code, fault_addr); } extern unsigned int early_recursion_flag; @@ -238,9 +258,9 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr) * result in a hard-to-debug panic. * * Keep in mind that not all vectors actually get here. Early - * fage faults, for example, are special. + * page faults, for example, are special. */ - if (fixup_exception(regs, trapnr)) + if (fixup_exception(regs, trapnr, regs->orig_ax, 0)) return; if (fixup_bug(regs, trapnr)) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index d99edb2d567b..cf16dfec2734 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -711,7 +711,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, int sig; /* Are we prepared to handle this kernel fault? */ - if (fixup_exception(regs, X86_TRAP_PF)) { + if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) { /* * Any interrupt that takes a fault gets the fixup. This makes * the below recursive fault logic only apply to a faults from -- cgit v1.2.3 From 9da3f2b74054406f87dff7101a569217ffceb29b Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 Aug 2018 22:14:20 +0200 Subject: x86/fault: BUG() when uaccess helpers fault on kernel addresses There have been multiple kernel vulnerabilities that permitted userspace to pass completely unchecked pointers through to userspace accessors: - the waitid() bug - commit 96ca579a1ecc ("waitid(): Add missing access_ok() checks") - the sg/bsg read/write APIs - the infiniband read/write APIs These don't happen all that often, but when they do happen, it is hard to test for them properly; and it is probably also hard to discover them with fuzzing. Even when an unmapped kernel address is supplied to such buggy code, it just returns -EFAULT instead of doing a proper BUG() or at least WARN(). Try to make such misbehaving code a bit more visible by refusing to do a fixup in the pagefault handler code when a userspace accessor causes a #PF on a kernel address and the current context isn't whitelisted. Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Cc: Andy Lutomirski Cc: kernel-hardening@lists.openwall.com Cc: dvyukov@google.com Cc: Masami Hiramatsu Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-7-jannh@google.com --- arch/x86/mm/extable.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++ fs/namespace.c | 2 ++ include/linux/sched.h | 6 ++++++ mm/maccess.c | 6 ++++++ 4 files changed, 72 insertions(+) (limited to 'arch') diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 856fa409c536..6521134057e8 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -117,11 +117,67 @@ __visible bool ex_handler_fprestore(const struct exception_table_entry *fixup, } EXPORT_SYMBOL_GPL(ex_handler_fprestore); +/* Helper to check whether a uaccess fault indicates a kernel bug. */ +static bool bogus_uaccess(struct pt_regs *regs, int trapnr, + unsigned long fault_addr) +{ + /* This is the normal case: #PF with a fault address in userspace. */ + if (trapnr == X86_TRAP_PF && fault_addr < TASK_SIZE_MAX) + return false; + + /* + * This code can be reached for machine checks, but only if the #MC + * handler has already decided that it looks like a candidate for fixup. + * This e.g. happens when attempting to access userspace memory which + * the CPU can't access because of uncorrectable bad memory. + */ + if (trapnr == X86_TRAP_MC) + return false; + + /* + * There are two remaining exception types we might encounter here: + * - #PF for faulting accesses to kernel addresses + * - #GP for faulting accesses to noncanonical addresses + * Complain about anything else. + */ + if (trapnr != X86_TRAP_PF && trapnr != X86_TRAP_GP) { + WARN(1, "unexpected trap %d in uaccess\n", trapnr); + return false; + } + + /* + * This is a faulting memory access in kernel space, on a kernel + * address, in a usercopy function. This can e.g. be caused by improper + * use of helpers like __put_user and by improper attempts to access + * userspace addresses in KERNEL_DS regions. + * The one (semi-)legitimate exception are probe_kernel_{read,write}(), + * which can be invoked from places like kgdb, /dev/mem (for reading) + * and privileged BPF code (for reading). + * The probe_kernel_*() functions set the kernel_uaccess_faults_ok flag + * to tell us that faulting on kernel addresses, and even noncanonical + * addresses, in a userspace accessor does not necessarily imply a + * kernel bug, root might just be doing weird stuff. + */ + if (current->kernel_uaccess_faults_ok) + return false; + + /* This is bad. Refuse the fixup so that we go into die(). */ + if (trapnr == X86_TRAP_PF) { + pr_emerg("BUG: pagefault on kernel address 0x%lx in non-whitelisted uaccess\n", + fault_addr); + } else { + pr_emerg("BUG: GPF in non-whitelisted uaccess (non-canonical address?)\n"); + } + return true; +} + __visible bool ex_handler_uaccess(const struct exception_table_entry *fixup, struct pt_regs *regs, int trapnr, unsigned long error_code, unsigned long fault_addr) { + if (bogus_uaccess(regs, trapnr, fault_addr)) + return false; regs->ip = ex_fixup_addr(fixup); return true; } @@ -132,6 +188,8 @@ __visible bool ex_handler_ext(const struct exception_table_entry *fixup, unsigned long error_code, unsigned long fault_addr) { + if (bogus_uaccess(regs, trapnr, fault_addr)) + return false; /* Special hack for uaccess_err */ current->thread.uaccess_err = 1; regs->ip = ex_fixup_addr(fixup); diff --git a/fs/namespace.c b/fs/namespace.c index 99186556f8d3..d86830c86ce8 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2642,6 +2642,7 @@ static long exact_copy_from_user(void *to, const void __user * from, if (!access_ok(VERIFY_READ, from, n)) return n; + current->kernel_uaccess_faults_ok++; while (n) { if (__get_user(c, f)) { memset(t, 0, n); @@ -2651,6 +2652,7 @@ static long exact_copy_from_user(void *to, const void __user * from, f++; n--; } + current->kernel_uaccess_faults_ok--; return n; } diff --git a/include/linux/sched.h b/include/linux/sched.h index 977cb57d7bc9..56dd65f1be4f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -739,6 +739,12 @@ struct task_struct { unsigned use_memdelay:1; #endif + /* + * May usercopy functions fault on kernel addresses? + * This is not just a single bit because this can potentially nest. + */ + unsigned int kernel_uaccess_faults_ok; + unsigned long atomic_flags; /* Flags requiring atomic access. */ struct restart_block restart_block; diff --git a/mm/maccess.c b/mm/maccess.c index ec00be51a24f..f3416632e5a4 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -30,8 +30,10 @@ long __probe_kernel_read(void *dst, const void *src, size_t size) set_fs(KERNEL_DS); pagefault_disable(); + current->kernel_uaccess_faults_ok++; ret = __copy_from_user_inatomic(dst, (__force const void __user *)src, size); + current->kernel_uaccess_faults_ok--; pagefault_enable(); set_fs(old_fs); @@ -58,7 +60,9 @@ long __probe_kernel_write(void *dst, const void *src, size_t size) set_fs(KERNEL_DS); pagefault_disable(); + current->kernel_uaccess_faults_ok++; ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); + current->kernel_uaccess_faults_ok--; pagefault_enable(); set_fs(old_fs); @@ -94,11 +98,13 @@ long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count) set_fs(KERNEL_DS); pagefault_disable(); + current->kernel_uaccess_faults_ok++; do { ret = __get_user(*dst++, (const char __user __force *)src++); } while (dst[-1] && ret == 0 && src - unsafe_addr < count); + current->kernel_uaccess_faults_ok--; dst[-1] = '\0'; pagefault_enable(); set_fs(old_fs); -- cgit v1.2.3 From 379e36d3f591cb62e781907edafea17d75e8c1fa Mon Sep 17 00:00:00 2001 From: Ludovic Desroches Date: Fri, 7 Sep 2018 10:18:51 +0200 Subject: ARM: dts: at91: sama5d2_ptc_ek: fix nand pinctrl The drive strength has to be set to medium otherwise some data corruption may happen. Signed-off-by: Ludovic Desroches Acked-by: Nicolas Ferre Signed-off-by: Alexandre Belloni --- arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch') diff --git a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts index b10dccd0958f..3b1baa8605a7 100644 --- a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts +++ b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts @@ -11,6 +11,7 @@ #include "sama5d2-pinfunc.h" #include #include +#include / { model = "Atmel SAMA5D2 PTC EK"; @@ -299,6 +300,7 @@ , ; bias-pull-up; + atmel,drive-strength = ; }; ale_cle_rdy_cs { -- cgit v1.2.3 From 13b91ed77a65cf3bf23353880245d0cbd9138294 Mon Sep 17 00:00:00 2001 From: Icenowy Zheng Date: Sun, 16 Sep 2018 12:34:09 +0800 Subject: ARM: dts: sun8i: drop A64 HDMI PHY fallback compatible from R40 DT The R40 HDMI PHY seems to be different to the A64 one, the A64 one has no input mux, but the R40 one has. Drop the A64 fallback compatible from the HDMI PHY node in R40 DT. Signed-off-by: Icenowy Zheng Signed-off-by: Maxime Ripard [wens@csie.org: Fix subject prefix order] Signed-off-by: Chen-Yu Tsai --- arch/arm/boot/dts/sun8i-r40.dtsi | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/arm/boot/dts/sun8i-r40.dtsi b/arch/arm/boot/dts/sun8i-r40.dtsi index ffd9f00f74a4..5f547c161baf 100644 --- a/arch/arm/boot/dts/sun8i-r40.dtsi +++ b/arch/arm/boot/dts/sun8i-r40.dtsi @@ -800,8 +800,7 @@ }; hdmi_phy: hdmi-phy@1ef0000 { - compatible = "allwinner,sun8i-r40-hdmi-phy", - "allwinner,sun50i-a64-hdmi-phy"; + compatible = "allwinner,sun8i-r40-hdmi-phy"; reg = <0x01ef0000 0x10000>; clocks = <&ccu CLK_BUS_HDMI1>, <&ccu CLK_HDMI_SLOW>, <&ccu 7>, <&ccu 16>; -- cgit v1.2.3 From 469ed9d823b7d240d6b9574f061ded7c3834c167 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Fri, 21 Sep 2018 16:34:04 +0100 Subject: arm64: hugetlb: Fix handling of young ptes In the contiguous bit hugetlb break-before-make code we assume that all hugetlb pages are young. In fact, remove_migration_pte is able to place an old hugetlb pte so this assumption is not valid. This patch fixes the contiguous hugetlb scanning code to preserve young ptes. Fixes: d8bdcff28764 ("arm64: hugetlb: Add break-before-make logic for contiguous entries") Signed-off-by: Steve Capper Signed-off-by: Will Deacon --- arch/arm64/mm/hugetlbpage.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 192b3ba07075..f85be2f8b140 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -117,11 +117,14 @@ static pte_t get_clear_flush(struct mm_struct *mm, /* * If HW_AFDBM is enabled, then the HW could turn on - * the dirty bit for any page in the set, so check - * them all. All hugetlb entries are already young. + * the dirty or accessed bit for any page in the set, + * so check them all. */ if (pte_dirty(pte)) orig_pte = pte_mkdirty(orig_pte); + + if (pte_young(pte)) + orig_pte = pte_mkyoung(orig_pte); } if (valid) { @@ -340,10 +343,13 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, if (!pte_same(orig_pte, pte)) changed = 1; - /* Make sure we don't lose the dirty state */ + /* Make sure we don't lose the dirty or young state */ if (pte_dirty(orig_pte)) pte = pte_mkdirty(pte); + if (pte_young(orig_pte)) + pte = pte_mkyoung(pte); + hugeprot = pte_pgprot(pte); for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot)); -- cgit v1.2.3 From 031e6e6b4e1277e76e73a6ab209095ad9bf3ce52 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Fri, 21 Sep 2018 16:34:05 +0100 Subject: arm64: hugetlb: Avoid unnecessary clearing in huge_ptep_set_access_flags For contiguous hugetlb, huge_ptep_set_access_flags performs a get_clear_flush (which then flushes the TLBs) even when no change of ptes is necessary. Unfortunately, this behaviour can lead to back-to-back page faults being generated when running with multiple threads that access the same contiguous huge page. Thread 1 | Thread 2 -----------------------------+------------------------------ hugetlb_fault | huge_ptep_set_access_flags | -> invalidate pte range | hugetlb_fault continue processing | wait for hugetlb_fault_mutex release mutex and return | huge_ptep_set_access_flags | -> invalidate pte range hugetlb_fault ... This patch changes huge_ptep_set_access_flags s.t. we first read the contiguous range of ptes (whilst preserving dirty information); the pte range is only then invalidated where necessary and this prevents further spurious page faults. Fixes: d8bdcff28764 ("arm64: hugetlb: Add break-before-make logic for contiguous entries") Reported-by: Lei Zhang Signed-off-by: Steve Capper Signed-off-by: Will Deacon --- arch/arm64/mm/hugetlbpage.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index f85be2f8b140..f58ea503ad01 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -323,11 +323,40 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, return get_clear_flush(mm, addr, ptep, pgsize, ncontig); } +/* + * huge_ptep_set_access_flags will update access flags (dirty, accesssed) + * and write permission. + * + * For a contiguous huge pte range we need to check whether or not write + * permission has to change only on the first pte in the set. Then for + * all the contiguous ptes we need to check whether or not there is a + * discrepancy between dirty or young. + */ +static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig) +{ + int i; + + if (pte_write(pte) != pte_write(huge_ptep_get(ptep))) + return 1; + + for (i = 0; i < ncontig; i++) { + pte_t orig_pte = huge_ptep_get(ptep + i); + + if (pte_dirty(pte) != pte_dirty(orig_pte)) + return 1; + + if (pte_young(pte) != pte_young(orig_pte)) + return 1; + } + + return 0; +} + int huge_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t pte, int dirty) { - int ncontig, i, changed = 0; + int ncontig, i; size_t pgsize = 0; unsigned long pfn = pte_pfn(pte), dpfn; pgprot_t hugeprot; @@ -339,9 +368,10 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize); dpfn = pgsize >> PAGE_SHIFT; + if (!__cont_access_flags_changed(ptep, pte, ncontig)) + return 0; + orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig); - if (!pte_same(orig_pte, pte)) - changed = 1; /* Make sure we don't lose the dirty or young state */ if (pte_dirty(orig_pte)) @@ -354,7 +384,7 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot)); - return changed; + return 1; } void huge_ptep_set_wrprotect(struct mm_struct *mm, -- cgit v1.2.3 From 3ab97942d0213b6583a5408630a8cbbfbf54730f Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 19 Sep 2018 17:14:01 -0700 Subject: ARM: dts: BCM63xx: Fix incorrect interrupt specifiers A number of our interrupts were incorrectly specified, fix both the PPI and SPI interrupts to be correct. Fixes: b5762cacc411 ("ARM: bcm63138: add NAND DT support") Fixes: 46d4bca0445a ("ARM: BCM63XX: add BCM63138 minimal Device Tree") Signed-off-by: Florian Fainelli --- arch/arm/boot/dts/bcm63138.dtsi | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/arm/boot/dts/bcm63138.dtsi b/arch/arm/boot/dts/bcm63138.dtsi index 43ee992ccdcf..6df61518776f 100644 --- a/arch/arm/boot/dts/bcm63138.dtsi +++ b/arch/arm/boot/dts/bcm63138.dtsi @@ -106,21 +106,23 @@ global_timer: timer@1e200 { compatible = "arm,cortex-a9-global-timer"; reg = <0x1e200 0x20>; - interrupts = ; + interrupts = ; clocks = <&axi_clk>; }; local_timer: local-timer@1e600 { compatible = "arm,cortex-a9-twd-timer"; reg = <0x1e600 0x20>; - interrupts = ; + interrupts = ; clocks = <&axi_clk>; }; twd_watchdog: watchdog@1e620 { compatible = "arm,cortex-a9-twd-wdt"; reg = <0x1e620 0x20>; - interrupts = ; + interrupts = ; }; armpll: armpll { @@ -158,7 +160,7 @@ serial0: serial@600 { compatible = "brcm,bcm6345-uart"; reg = <0x600 0x1b>; - interrupts = ; + interrupts = ; clocks = <&periph_clk>; clock-names = "periph"; status = "disabled"; @@ -167,7 +169,7 @@ serial1: serial@620 { compatible = "brcm,bcm6345-uart"; reg = <0x620 0x1b>; - interrupts = ; + interrupts = ; clocks = <&periph_clk>; clock-names = "periph"; status = "disabled"; @@ -180,7 +182,7 @@ reg = <0x2000 0x600>, <0xf0 0x10>; reg-names = "nand", "nand-int-base"; status = "disabled"; - interrupts = ; + interrupts = ; interrupt-names = "nand"; }; -- cgit v1.2.3 From 082dc55e3c5e559b0e6855c0de23ebd674bcc91e Mon Sep 17 00:00:00 2001 From: Amelie Delaunay Date: Thu, 20 Sep 2018 18:34:16 +0200 Subject: ARM: dts: stm32: update SPI6 dmas property on stm32mp157c Remove unused parameter from SPI6 dmas property on stm32mp157c SoC. Fixes: dc3f8c86c10d ("ARM: dts: stm32: add SPI support on stm32mp157c") Signed-off-by: Amelie Delaunay Signed-off-by: Alexandre Torgue [olof: Without this patch, SPI6 will fall back to interrupt mode with lower perfmance] Signed-off-by: Olof Johansson --- arch/arm/boot/dts/stm32mp157c.dtsi | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/arm/boot/dts/stm32mp157c.dtsi b/arch/arm/boot/dts/stm32mp157c.dtsi index 661be948ab74..185541a5b69f 100644 --- a/arch/arm/boot/dts/stm32mp157c.dtsi +++ b/arch/arm/boot/dts/stm32mp157c.dtsi @@ -1078,8 +1078,8 @@ interrupts = ; clocks = <&rcc SPI6_K>; resets = <&rcc SPI6_R>; - dmas = <&mdma1 34 0x0 0x40008 0x0 0x0 0>, - <&mdma1 35 0x0 0x40002 0x0 0x0 0>; + dmas = <&mdma1 34 0x0 0x40008 0x0 0x0>, + <&mdma1 35 0x0 0x40002 0x0 0x0>; dma-names = "rx", "tx"; status = "disabled"; }; -- cgit v1.2.3 From d26c25a9d19b5976b319af528886f89cf455692d Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Thu, 27 Sep 2018 16:53:21 +0100 Subject: arm64: KVM: Tighten guest core register access from userspace We currently allow userspace to access the core register file in about any possible way, including straddling multiple registers and doing unaligned accesses. This is not the expected use of the ABI, and nobody is actually using it that way. Let's tighten it by explicitly checking the size and alignment for each field of the register file. Cc: Fixes: 2f4a07c5f9fe ("arm64: KVM: guest one-reg interface") Reviewed-by: Christoffer Dall Reviewed-by: Mark Rutland Signed-off-by: Dave Martin [maz: rewrote Dave's initial patch to be more easily backported] Signed-off-by: Marc Zyngier Signed-off-by: Will Deacon --- arch/arm64/kvm/guest.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'arch') diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 07256b08226c..3088463bafc1 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -57,6 +57,45 @@ static u64 core_reg_offset_from_id(u64 id) return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE); } +static int validate_core_offset(const struct kvm_one_reg *reg) +{ + u64 off = core_reg_offset_from_id(reg->id); + int size; + + switch (off) { + case KVM_REG_ARM_CORE_REG(regs.regs[0]) ... + KVM_REG_ARM_CORE_REG(regs.regs[30]): + case KVM_REG_ARM_CORE_REG(regs.sp): + case KVM_REG_ARM_CORE_REG(regs.pc): + case KVM_REG_ARM_CORE_REG(regs.pstate): + case KVM_REG_ARM_CORE_REG(sp_el1): + case KVM_REG_ARM_CORE_REG(elr_el1): + case KVM_REG_ARM_CORE_REG(spsr[0]) ... + KVM_REG_ARM_CORE_REG(spsr[KVM_NR_SPSR - 1]): + size = sizeof(__u64); + break; + + case KVM_REG_ARM_CORE_REG(fp_regs.vregs[0]) ... + KVM_REG_ARM_CORE_REG(fp_regs.vregs[31]): + size = sizeof(__uint128_t); + break; + + case KVM_REG_ARM_CORE_REG(fp_regs.fpsr): + case KVM_REG_ARM_CORE_REG(fp_regs.fpcr): + size = sizeof(__u32); + break; + + default: + return -EINVAL; + } + + if (KVM_REG_SIZE(reg->id) == size && + IS_ALIGNED(off, size / sizeof(__u32))) + return 0; + + return -EINVAL; +} + static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { /* @@ -76,6 +115,9 @@ static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs) return -ENOENT; + if (validate_core_offset(reg)) + return -EINVAL; + if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id))) return -EFAULT; @@ -98,6 +140,9 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs) return -ENOENT; + if (validate_core_offset(reg)) + return -EINVAL; + if (KVM_REG_SIZE(reg->id) > sizeof(tmp)) return -EINVAL; -- cgit v1.2.3 From 2a3f93459d689d990b3ecfbe782fec89b97d3279 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 27 Sep 2018 16:53:22 +0100 Subject: arm64: KVM: Sanitize PSTATE.M when being set from userspace Not all execution modes are valid for a guest, and some of them depend on what the HW actually supports. Let's verify that what userspace provides is compatible with both the VM settings and the HW capabilities. Cc: Fixes: 0d854a60b1d7 ("arm64: KVM: enable initialization of a 32bit vcpu") Reviewed-by: Christoffer Dall Reviewed-by: Mark Rutland Reviewed-by: Dave Martin Signed-off-by: Marc Zyngier Signed-off-by: Will Deacon --- arch/arm64/kvm/guest.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 3088463bafc1..a6c9fbaeaefc 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -152,17 +152,25 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) } if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) { - u32 mode = (*(u32 *)valp) & PSR_AA32_MODE_MASK; + u64 mode = (*(u64 *)valp) & PSR_AA32_MODE_MASK; switch (mode) { case PSR_AA32_MODE_USR: + if (!system_supports_32bit_el0()) + return -EINVAL; + break; case PSR_AA32_MODE_FIQ: case PSR_AA32_MODE_IRQ: case PSR_AA32_MODE_SVC: case PSR_AA32_MODE_ABT: case PSR_AA32_MODE_UND: + if (!vcpu_el1_is_32bit(vcpu)) + return -EINVAL; + break; case PSR_MODE_EL0t: case PSR_MODE_EL1t: case PSR_MODE_EL1h: + if (vcpu_el1_is_32bit(vcpu)) + return -EINVAL; break; default: err = -EINVAL; -- cgit v1.2.3