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f56141e3e2
If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
155 lines
5.4 KiB
C
155 lines
5.4 KiB
C
/*
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* Copyright (C) 2002-2003 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*/
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#ifndef _ASM_IA64_THREAD_INFO_H
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#define _ASM_IA64_THREAD_INFO_H
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#ifndef ASM_OFFSETS_C
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#include <asm/asm-offsets.h>
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#endif
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#include <asm/processor.h>
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#include <asm/ptrace.h>
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#ifndef __ASSEMBLY__
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/*
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* On IA-64, we want to keep the task structure and kernel stack together, so they can be
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* mapped by a single TLB entry and so they can be addressed by the "current" pointer
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* without having to do pointer masking.
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*/
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struct thread_info {
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struct task_struct *task; /* XXX not really needed, except for dup_task_struct() */
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struct exec_domain *exec_domain;/* execution domain */
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__u32 flags; /* thread_info flags (see TIF_*) */
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__u32 cpu; /* current CPU */
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__u32 last_cpu; /* Last CPU thread ran on */
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__u32 status; /* Thread synchronous flags */
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mm_segment_t addr_limit; /* user-level address space limit */
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int preempt_count; /* 0=premptable, <0=BUG; will also serve as bh-counter */
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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__u64 ac_stamp;
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__u64 ac_leave;
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__u64 ac_stime;
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__u64 ac_utime;
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#endif
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};
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#define THREAD_SIZE KERNEL_STACK_SIZE
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.task = &tsk, \
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.exec_domain = &default_exec_domain, \
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.flags = 0, \
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.cpu = 0, \
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.addr_limit = KERNEL_DS, \
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.preempt_count = INIT_PREEMPT_COUNT, \
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}
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#ifndef ASM_OFFSETS_C
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/* how to get the thread information struct from C */
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#define current_thread_info() ((struct thread_info *) ((char *) current + IA64_TASK_SIZE))
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#define alloc_thread_info_node(tsk, node) \
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((struct thread_info *) ((char *) (tsk) + IA64_TASK_SIZE))
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#define task_thread_info(tsk) ((struct thread_info *) ((char *) (tsk) + IA64_TASK_SIZE))
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#else
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#define current_thread_info() ((struct thread_info *) 0)
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#define alloc_thread_info_node(tsk, node) ((struct thread_info *) 0)
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#define task_thread_info(tsk) ((struct thread_info *) 0)
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#endif
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#define free_thread_info(ti) /* nothing */
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#define task_stack_page(tsk) ((void *)(tsk))
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#define __HAVE_THREAD_FUNCTIONS
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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#define setup_thread_stack(p, org) \
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*task_thread_info(p) = *task_thread_info(org); \
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task_thread_info(p)->ac_stime = 0; \
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task_thread_info(p)->ac_utime = 0; \
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task_thread_info(p)->task = (p);
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#else
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#define setup_thread_stack(p, org) \
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*task_thread_info(p) = *task_thread_info(org); \
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task_thread_info(p)->task = (p);
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#endif
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#define end_of_stack(p) (unsigned long *)((void *)(p) + IA64_RBS_OFFSET)
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#define alloc_task_struct_node(node) \
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({ \
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struct page *page = alloc_pages_node(node, GFP_KERNEL | __GFP_COMP, \
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KERNEL_STACK_SIZE_ORDER); \
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struct task_struct *ret = page ? page_address(page) : NULL; \
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\
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ret; \
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})
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#define free_task_struct(tsk) free_pages((unsigned long) (tsk), KERNEL_STACK_SIZE_ORDER)
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#endif /* !__ASSEMBLY */
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/*
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* thread information flags
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* - these are process state flags that various assembly files may need to access
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* - pending work-to-be-done flags are in least-significant 16 bits, other flags
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* in top 16 bits
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*/
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#define TIF_SIGPENDING 0 /* signal pending */
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#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
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#define TIF_SYSCALL_TRACE 2 /* syscall trace active */
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#define TIF_SYSCALL_AUDIT 3 /* syscall auditing active */
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#define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */
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#define TIF_NOTIFY_RESUME 6 /* resumption notification requested */
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#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
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#define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */
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#define TIF_DB_DISABLED 19 /* debug trap disabled for fsyscall */
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#define TIF_RESTORE_RSE 21 /* user RBS is newer than kernel RBS */
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#define TIF_POLLING_NRFLAG 22 /* idle is polling for TIF_NEED_RESCHED */
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#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
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#define _TIF_SYSCALL_TRACEAUDIT (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP)
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#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
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#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
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#define _TIF_MCA_INIT (1 << TIF_MCA_INIT)
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#define _TIF_DB_DISABLED (1 << TIF_DB_DISABLED)
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#define _TIF_RESTORE_RSE (1 << TIF_RESTORE_RSE)
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#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
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/* "work to do on user-return" bits */
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#define TIF_ALLWORK_MASK (_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SYSCALL_AUDIT|\
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_TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE)
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/* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT */
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#define TIF_WORK_MASK (TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
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#define TS_RESTORE_SIGMASK 2 /* restore signal mask in do_signal() */
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#ifndef __ASSEMBLY__
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#define HAVE_SET_RESTORE_SIGMASK 1
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static inline void set_restore_sigmask(void)
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{
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struct thread_info *ti = current_thread_info();
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ti->status |= TS_RESTORE_SIGMASK;
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WARN_ON(!test_bit(TIF_SIGPENDING, &ti->flags));
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}
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static inline void clear_restore_sigmask(void)
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{
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current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
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}
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static inline bool test_restore_sigmask(void)
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{
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return current_thread_info()->status & TS_RESTORE_SIGMASK;
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}
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static inline bool test_and_clear_restore_sigmask(void)
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{
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struct thread_info *ti = current_thread_info();
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if (!(ti->status & TS_RESTORE_SIGMASK))
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return false;
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ti->status &= ~TS_RESTORE_SIGMASK;
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return true;
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_IA64_THREAD_INFO_H */
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