diff options
Diffstat (limited to 'arch/x86/entry/vsyscall')
| -rw-r--r-- | arch/x86/entry/vsyscall/Makefile | 3 | ||||
| -rw-r--r-- | arch/x86/entry/vsyscall/vsyscall_64.c | 41 | ||||
| -rw-r--r-- | arch/x86/entry/vsyscall/vsyscall_emu_64.S | 3 | ||||
| -rw-r--r-- | arch/x86/entry/vsyscall/vsyscall_gtod.c | 83 |
4 files changed, 37 insertions, 93 deletions
diff --git a/arch/x86/entry/vsyscall/Makefile b/arch/x86/entry/vsyscall/Makefile index a9f4856f622a..93c1b3e949a7 100644 --- a/arch/x86/entry/vsyscall/Makefile +++ b/arch/x86/entry/vsyscall/Makefile @@ -1,7 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-only # # Makefile for the x86 low level vsyscall code # -obj-y := vsyscall_gtod.o - obj-$(CONFIG_X86_VSYSCALL_EMULATION) += vsyscall_64.o vsyscall_emu_64.o diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index d9d81ad7a400..e7c596dea947 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -42,9 +42,11 @@ #define CREATE_TRACE_POINTS #include "vsyscall_trace.h" -static enum { EMULATE, NONE } vsyscall_mode = +static enum { EMULATE, XONLY, NONE } vsyscall_mode __ro_after_init = #ifdef CONFIG_LEGACY_VSYSCALL_NONE NONE; +#elif defined(CONFIG_LEGACY_VSYSCALL_XONLY) + XONLY; #else EMULATE; #endif @@ -54,6 +56,8 @@ static int __init vsyscall_setup(char *str) if (str) { if (!strcmp("emulate", str)) vsyscall_mode = EMULATE; + else if (!strcmp("xonly", str)) + vsyscall_mode = XONLY; else if (!strcmp("none", str)) vsyscall_mode = NONE; else @@ -106,14 +110,15 @@ static bool write_ok_or_segv(unsigned long ptr, size_t size) thread->cr2 = ptr; thread->trap_nr = X86_TRAP_PF; - force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)ptr, current); + force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)ptr); return false; } else { return true; } } -bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) +bool emulate_vsyscall(unsigned long error_code, + struct pt_regs *regs, unsigned long address) { struct task_struct *tsk; unsigned long caller; @@ -122,6 +127,22 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) long ret; unsigned long orig_dx; + /* Write faults or kernel-privilege faults never get fixed up. */ + if ((error_code & (X86_PF_WRITE | X86_PF_USER)) != X86_PF_USER) + return false; + + if (!(error_code & X86_PF_INSTR)) { + /* Failed vsyscall read */ + if (vsyscall_mode == EMULATE) + return false; + + /* + * User code tried and failed to read the vsyscall page. + */ + warn_bad_vsyscall(KERN_INFO, regs, "vsyscall read attempt denied -- look up the vsyscall kernel parameter if you need a workaround"); + return false; + } + /* * No point in checking CS -- the only way to get here is a user mode * trap to a high address, which means that we're in 64-bit user code. @@ -268,7 +289,7 @@ do_ret: return true; sigsegv: - force_sig(SIGSEGV, current); + force_sig(SIGSEGV); return true; } @@ -284,7 +305,7 @@ static const char *gate_vma_name(struct vm_area_struct *vma) static const struct vm_operations_struct gate_vma_ops = { .name = gate_vma_name, }; -static struct vm_area_struct gate_vma = { +static struct vm_area_struct gate_vma __ro_after_init = { .vm_start = VSYSCALL_ADDR, .vm_end = VSYSCALL_ADDR + PAGE_SIZE, .vm_page_prot = PAGE_READONLY_EXEC, @@ -357,12 +378,20 @@ void __init map_vsyscall(void) extern char __vsyscall_page; unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page); - if (vsyscall_mode != NONE) { + /* + * For full emulation, the page needs to exist for real. In + * execute-only mode, there is no PTE at all backing the vsyscall + * page. + */ + if (vsyscall_mode == EMULATE) { __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall, PAGE_KERNEL_VVAR); set_vsyscall_pgtable_user_bits(swapper_pg_dir); } + if (vsyscall_mode == XONLY) + gate_vma.vm_flags = VM_EXEC; + BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) != (unsigned long)VSYSCALL_ADDR); } diff --git a/arch/x86/entry/vsyscall/vsyscall_emu_64.S b/arch/x86/entry/vsyscall/vsyscall_emu_64.S index c9596a9af159..2e203f3a25a7 100644 --- a/arch/x86/entry/vsyscall/vsyscall_emu_64.S +++ b/arch/x86/entry/vsyscall/vsyscall_emu_64.S @@ -1,9 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * vsyscall_emu_64.S: Vsyscall emulation page * * Copyright (c) 2011 Andy Lutomirski - * - * Subject to the GNU General Public License, version 2 */ #include <linux/linkage.h> diff --git a/arch/x86/entry/vsyscall/vsyscall_gtod.c b/arch/x86/entry/vsyscall/vsyscall_gtod.c deleted file mode 100644 index cfcdba082feb..000000000000 --- a/arch/x86/entry/vsyscall/vsyscall_gtod.c +++ /dev/null @@ -1,83 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE - * Copyright 2003 Andi Kleen, SuSE Labs. - * - * Modified for x86 32 bit architecture by - * Stefani Seibold <stefani@seibold.net> - * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany - * - * Thanks to hpa@transmeta.com for some useful hint. - * Special thanks to Ingo Molnar for his early experience with - * a different vsyscall implementation for Linux/IA32 and for the name. - * - */ - -#include <linux/timekeeper_internal.h> -#include <asm/vgtod.h> -#include <asm/vvar.h> - -int vclocks_used __read_mostly; - -DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data); - -void update_vsyscall_tz(void) -{ - vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest; - vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime; -} - -void update_vsyscall(struct timekeeper *tk) -{ - int vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode; - struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data; - struct vgtod_ts *base; - u64 nsec; - - /* Mark the new vclock used. */ - BUILD_BUG_ON(VCLOCK_MAX >= 32); - WRITE_ONCE(vclocks_used, READ_ONCE(vclocks_used) | (1 << vclock_mode)); - - gtod_write_begin(vdata); - - /* copy vsyscall data */ - vdata->vclock_mode = vclock_mode; - vdata->cycle_last = tk->tkr_mono.cycle_last; - vdata->mask = tk->tkr_mono.mask; - vdata->mult = tk->tkr_mono.mult; - vdata->shift = tk->tkr_mono.shift; - - base = &vdata->basetime[CLOCK_REALTIME]; - base->sec = tk->xtime_sec; - base->nsec = tk->tkr_mono.xtime_nsec; - - base = &vdata->basetime[CLOCK_TAI]; - base->sec = tk->xtime_sec + (s64)tk->tai_offset; - base->nsec = tk->tkr_mono.xtime_nsec; - - base = &vdata->basetime[CLOCK_MONOTONIC]; - base->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - nsec = tk->tkr_mono.xtime_nsec; - nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift); - while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { - nsec -= ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift; - base->sec++; - } - base->nsec = nsec; - - base = &vdata->basetime[CLOCK_REALTIME_COARSE]; - base->sec = tk->xtime_sec; - base->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; - - base = &vdata->basetime[CLOCK_MONOTONIC_COARSE]; - base->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; - nsec += tk->wall_to_monotonic.tv_nsec; - while (nsec >= NSEC_PER_SEC) { - nsec -= NSEC_PER_SEC; - base->sec++; - } - base->nsec = nsec; - - gtod_write_end(vdata); -} |