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https://github.com/torvalds/linux
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eab0c6089b
Currently architectures have to override every routine that probes kernel memory, which includes a pure read and strcpy, both in strict and not strict variants. Just provide a single arch hooks instead to make sure all architectures cover all the cases. [akpm@linux-foundation.org: fix !CONFIG_X86_64 build] 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/20200521152301.2587579-11-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
35 lines
919 B
C
35 lines
919 B
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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bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool strict)
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{
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unsigned long vaddr = (unsigned long)unsafe_src;
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if (!strict)
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return true;
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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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bool probe_kernel_read_allowed(const void *unsafe_src, size_t size, bool strict)
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{
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if (!strict)
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return true;
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return (unsigned long)unsafe_src >= TASK_SIZE_MAX;
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}
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#endif
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