forked from Minki/linux
6d13de1489
As we've done with VFS, string operations, etc, reject usercopy sizes larger than INT_MAX, which would be nice to have for catching bugs related to size calculation overflows[1]. This adds 10 bytes to x86_64 defconfig text and 1980 bytes to the data section: text data bss dec hex filename 19691167 5134320 1646664 26472151 193eed7 vmlinux.before 19691177 5136300 1646664 26474141 193f69d vmlinux.after [1] https://marc.info/?l=linux-s390&m=156631939010493&w=2 Link: http://lkml.kernel.org/r/201908251612.F9902D7A@keescook Signed-off-by: Kees Cook <keescook@chromium.org> Suggested-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
163 lines
4.1 KiB
C
163 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* thread_info.h: common low-level thread information accessors
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*
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds
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*/
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#ifndef _LINUX_THREAD_INFO_H
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#define _LINUX_THREAD_INFO_H
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#include <linux/types.h>
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#include <linux/bug.h>
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#include <linux/restart_block.h>
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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/*
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* For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
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* definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
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* including <asm/current.h> can cause a circular dependency on some platforms.
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*/
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#include <asm/current.h>
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#define current_thread_info() ((struct thread_info *)current)
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#endif
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#include <linux/bitops.h>
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/*
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* For per-arch arch_within_stack_frames() implementations, defined in
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* asm/thread_info.h.
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*/
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enum {
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BAD_STACK = -1,
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NOT_STACK = 0,
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GOOD_FRAME,
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GOOD_STACK,
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};
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#include <asm/thread_info.h>
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#ifdef __KERNEL__
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#ifndef THREAD_ALIGN
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#define THREAD_ALIGN THREAD_SIZE
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#endif
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#define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
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/*
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* flag set/clear/test wrappers
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* - pass TIF_xxxx constants to these functions
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*/
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static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline void update_ti_thread_flag(struct thread_info *ti, int flag,
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bool value)
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{
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if (value)
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set_ti_thread_flag(ti, flag);
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else
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clear_ti_thread_flag(ti, flag);
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}
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static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_bit(flag, (unsigned long *)&ti->flags);
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}
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#define set_thread_flag(flag) \
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set_ti_thread_flag(current_thread_info(), flag)
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#define clear_thread_flag(flag) \
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clear_ti_thread_flag(current_thread_info(), flag)
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#define update_thread_flag(flag, value) \
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update_ti_thread_flag(current_thread_info(), flag, value)
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#define test_and_set_thread_flag(flag) \
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test_and_set_ti_thread_flag(current_thread_info(), flag)
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#define test_and_clear_thread_flag(flag) \
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test_and_clear_ti_thread_flag(current_thread_info(), flag)
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#define test_thread_flag(flag) \
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test_ti_thread_flag(current_thread_info(), flag)
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#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
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#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
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static inline int arch_within_stack_frames(const void * const stack,
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const void * const stackend,
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const void *obj, unsigned long len)
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{
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return 0;
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}
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#endif
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#ifdef CONFIG_HARDENED_USERCOPY
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extern void __check_object_size(const void *ptr, unsigned long n,
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bool to_user);
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static __always_inline void check_object_size(const void *ptr, unsigned long n,
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bool to_user)
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{
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if (!__builtin_constant_p(n))
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__check_object_size(ptr, n, to_user);
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}
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#else
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static inline void check_object_size(const void *ptr, unsigned long n,
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bool to_user)
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{ }
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#endif /* CONFIG_HARDENED_USERCOPY */
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extern void __compiletime_error("copy source size is too small")
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__bad_copy_from(void);
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extern void __compiletime_error("copy destination size is too small")
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__bad_copy_to(void);
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static inline void copy_overflow(int size, unsigned long count)
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{
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WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
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}
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static __always_inline __must_check bool
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check_copy_size(const void *addr, size_t bytes, bool is_source)
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{
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int sz = __compiletime_object_size(addr);
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if (unlikely(sz >= 0 && sz < bytes)) {
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if (!__builtin_constant_p(bytes))
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copy_overflow(sz, bytes);
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else if (is_source)
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__bad_copy_from();
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else
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__bad_copy_to();
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return false;
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}
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if (WARN_ON_ONCE(bytes > INT_MAX))
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return false;
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check_object_size(addr, bytes, is_source);
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return true;
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}
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#ifndef arch_setup_new_exec
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static inline void arch_setup_new_exec(void) { }
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#endif
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#endif /* __KERNEL__ */
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#endif /* _LINUX_THREAD_INFO_H */
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