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- /* SPDX-License-Identifier: GPL-2.0-only */
- /*
- * Copyright (c) 2020 Christoph Hellwig.
- *
- * Support for "universal" pointers that can point to either kernel or userspace
- * memory.
- */
- #ifndef _LINUX_SOCKPTR_H
- #define _LINUX_SOCKPTR_H
- #include <linux/slab.h>
- #include <linux/uaccess.h>
- typedef struct {
- union {
- void *kernel;
- void __user *user;
- };
- bool is_kernel : 1;
- } sockptr_t;
- static inline bool sockptr_is_kernel(sockptr_t sockptr)
- {
- return sockptr.is_kernel;
- }
- static inline sockptr_t KERNEL_SOCKPTR(void *p)
- {
- return (sockptr_t) { .kernel = p, .is_kernel = true };
- }
- static inline sockptr_t USER_SOCKPTR(void __user *p)
- {
- return (sockptr_t) { .user = p };
- }
- static inline bool sockptr_is_null(sockptr_t sockptr)
- {
- if (sockptr_is_kernel(sockptr))
- return !sockptr.kernel;
- return !sockptr.user;
- }
- static inline int copy_from_sockptr_offset(void *dst, sockptr_t src,
- size_t offset, size_t size)
- {
- if (!sockptr_is_kernel(src))
- return copy_from_user(dst, src.user + offset, size);
- memcpy(dst, src.kernel + offset, size);
- return 0;
- }
- static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size)
- {
- return copy_from_sockptr_offset(dst, src, 0, size);
- }
- static inline int copy_to_sockptr_offset(sockptr_t dst, size_t offset,
- const void *src, size_t size)
- {
- if (!sockptr_is_kernel(dst))
- return copy_to_user(dst.user + offset, src, size);
- memcpy(dst.kernel + offset, src, size);
- return 0;
- }
- static inline int copy_to_sockptr(sockptr_t dst, const void *src, size_t size)
- {
- return copy_to_sockptr_offset(dst, 0, src, size);
- }
- static inline void *memdup_sockptr(sockptr_t src, size_t len)
- {
- void *p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN);
- if (!p)
- return ERR_PTR(-ENOMEM);
- if (copy_from_sockptr(p, src, len)) {
- kfree(p);
- return ERR_PTR(-EFAULT);
- }
- return p;
- }
- static inline void *memdup_sockptr_nul(sockptr_t src, size_t len)
- {
- char *p = kmalloc_track_caller(len + 1, GFP_KERNEL);
- if (!p)
- return ERR_PTR(-ENOMEM);
- if (copy_from_sockptr(p, src, len)) {
- kfree(p);
- return ERR_PTR(-EFAULT);
- }
- p[len] = '\0';
- return p;
- }
- static inline long strncpy_from_sockptr(char *dst, sockptr_t src, size_t count)
- {
- if (sockptr_is_kernel(src)) {
- size_t len = min(strnlen(src.kernel, count - 1) + 1, count);
- memcpy(dst, src.kernel, len);
- return len;
- }
- return strncpy_from_user(dst, src.user, count);
- }
- static inline int check_zeroed_sockptr(sockptr_t src, size_t offset,
- size_t size)
- {
- if (!sockptr_is_kernel(src))
- return check_zeroed_user(src.user + offset, size);
- return memchr_inv(src.kernel + offset, 0, size) == NULL;
- }
- #endif /* _LINUX_SOCKPTR_H */
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