new primitive: vmemdup_user()
similar to memdup_user(), but does *not* guarantee that result will be physically contiguous; use only in cases where that's not a requirement and free it with kvfree(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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@ -11,6 +11,7 @@
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extern char *strndup_user(const char __user *, long);
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extern char *strndup_user(const char __user *, long);
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extern void *memdup_user(const void __user *, size_t);
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extern void *memdup_user(const void __user *, size_t);
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extern void *vmemdup_user(const void __user *, size_t);
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extern void *memdup_user_nul(const void __user *, size_t);
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extern void *memdup_user_nul(const void __user *, size_t);
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/*
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/*
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29
mm/util.c
29
mm/util.c
@ -150,7 +150,8 @@ EXPORT_SYMBOL(kmemdup_nul);
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* @src: source address in user space
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* @src: source address in user space
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* @len: number of bytes to copy
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* @len: number of bytes to copy
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*
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*
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* Returns an ERR_PTR() on failure.
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* Returns an ERR_PTR() on failure. Result is physically
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* contiguous, to be freed by kfree().
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*/
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*/
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void *memdup_user(const void __user *src, size_t len)
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void *memdup_user(const void __user *src, size_t len)
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{
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{
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@ -169,6 +170,32 @@ void *memdup_user(const void __user *src, size_t len)
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}
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}
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EXPORT_SYMBOL(memdup_user);
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EXPORT_SYMBOL(memdup_user);
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/**
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* vmemdup_user - duplicate memory region from user space
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*
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* @src: source address in user space
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* @len: number of bytes to copy
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*
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* Returns an ERR_PTR() on failure. Result may be not
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* physically contiguous. Use kvfree() to free.
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*/
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void *vmemdup_user(const void __user *src, size_t len)
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{
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void *p;
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p = kvmalloc(len, GFP_USER);
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if (!p)
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return ERR_PTR(-ENOMEM);
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if (copy_from_user(p, src, len)) {
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kvfree(p);
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return ERR_PTR(-EFAULT);
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}
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return p;
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}
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EXPORT_SYMBOL(vmemdup_user);
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/*
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/*
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* strndup_user - duplicate an existing string from user space
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* strndup_user - duplicate an existing string from user space
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* @s: The string to duplicate
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* @s: The string to duplicate
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