c4cb164426
This matches the naming of strncpy_from_user_nofault, and also makes it more clear what the function is supposed to do. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200521152301.2587579-8-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#ifdef CONFIG_X86_64
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static __always_inline u64 canonical_address(u64 vaddr, u8 vaddr_bits)
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{
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return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits);
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}
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static __always_inline bool invalid_probe_range(u64 vaddr)
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{
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/*
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* Range covering the highest possible canonical userspace address
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* as well as non-canonical address range. For the canonical range
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* we also need to include the userspace guard page.
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*/
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return vaddr < TASK_SIZE_MAX + PAGE_SIZE ||
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canonical_address(vaddr, boot_cpu_data.x86_virt_bits) != vaddr;
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}
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#else
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static __always_inline bool invalid_probe_range(u64 vaddr)
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{
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return vaddr < TASK_SIZE_MAX;
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}
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#endif
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long probe_kernel_read_strict(void *dst, const void *src, size_t size)
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{
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if (unlikely(invalid_probe_range((unsigned long)src)))
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return -EFAULT;
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return __probe_kernel_read(dst, src, size);
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}
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long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
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{
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if (unlikely(invalid_probe_range((unsigned long)unsafe_addr)))
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return -EFAULT;
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return __strncpy_from_unsafe(dst, unsafe_addr, count);
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}
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