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mm/maccess.c
1.61 KB
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/* * Access kernel memory without faulting. */ |
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#include <linux/module.h> #include <linux/mm.h> |
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#include <linux/uaccess.h> |
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/** * probe_kernel_read(): safely attempt to read from a location * @dst: pointer to the buffer that shall take the data * @src: address to read from * @size: size of the data chunk * * Safely read from address @src to the buffer at @dst. If a kernel fault * happens, handle that and return -EFAULT. */ |
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long __weak probe_kernel_read(void *dst, void *src, size_t size) __attribute__((alias("__probe_kernel_read"))); long __probe_kernel_read(void *dst, void *src, size_t size) |
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{ long ret; |
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mm_segment_t old_fs = get_fs(); |
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set_fs(KERNEL_DS); |
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pagefault_disable(); ret = __copy_from_user_inatomic(dst, (__force const void __user *)src, size); pagefault_enable(); |
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set_fs(old_fs); |
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return ret ? -EFAULT : 0; } EXPORT_SYMBOL_GPL(probe_kernel_read); /** * probe_kernel_write(): safely attempt to write to a location * @dst: address to write to * @src: pointer to the data that shall be written * @size: size of the data chunk * * Safely write to address @dst from the buffer at @src. If a kernel fault * happens, handle that and return -EFAULT. */ |
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long __weak probe_kernel_write(void *dst, void *src, size_t size) __attribute__((alias("__probe_kernel_write"))); long __probe_kernel_write(void *dst, void *src, size_t size) |
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{ long ret; |
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mm_segment_t old_fs = get_fs(); |
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set_fs(KERNEL_DS); |
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pagefault_disable(); ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); pagefault_enable(); |
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set_fs(old_fs); |
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return ret ? -EFAULT : 0; } EXPORT_SYMBOL_GPL(probe_kernel_write); |