1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (c) 2020 Christoph Hellwig.
5 * Support for "universal" pointers that can point to either kernel or userspace
8 #ifndef _LINUX_SOCKPTR_H
9 #define _LINUX_SOCKPTR_H
11 #include <linux/compiler.h>
12 #include <linux/slab.h>
13 #include <linux/uaccess.h>
15 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
21 static inline bool sockptr_is_kernel(sockptr_t sockptr)
23 return (unsigned long)sockptr.kernel >= TASK_SIZE;
26 static inline sockptr_t KERNEL_SOCKPTR(void *p)
28 return (sockptr_t) { .kernel = p };
30 #else /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
39 static inline bool sockptr_is_kernel(sockptr_t sockptr)
41 return sockptr.is_kernel;
44 static inline sockptr_t KERNEL_SOCKPTR(void *p)
46 return (sockptr_t) { .kernel = p, .is_kernel = true };
48 #endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
50 static inline int __must_check init_user_sockptr(sockptr_t *sp, void __user *p,
53 if (!access_ok(p, size))
55 *sp = (sockptr_t) { .user = p };
59 static inline bool sockptr_is_null(sockptr_t sockptr)
61 if (sockptr_is_kernel(sockptr))
62 return !sockptr.kernel;
66 static inline int copy_from_sockptr_offset(void *dst, sockptr_t src,
67 size_t offset, size_t size)
69 if (!sockptr_is_kernel(src))
70 return copy_from_user(dst, src.user + offset, size);
71 memcpy(dst, src.kernel + offset, size);
75 static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size)
77 return copy_from_sockptr_offset(dst, src, 0, size);
80 static inline int copy_to_sockptr_offset(sockptr_t dst, size_t offset,
81 const void *src, size_t size)
83 if (!sockptr_is_kernel(dst))
84 return copy_to_user(dst.user + offset, src, size);
85 memcpy(dst.kernel + offset, src, size);
89 static inline void *memdup_sockptr(sockptr_t src, size_t len)
91 void *p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN);
94 return ERR_PTR(-ENOMEM);
95 if (copy_from_sockptr(p, src, len)) {
97 return ERR_PTR(-EFAULT);
102 static inline void *memdup_sockptr_nul(sockptr_t src, size_t len)
104 char *p = kmalloc_track_caller(len + 1, GFP_KERNEL);
107 return ERR_PTR(-ENOMEM);
108 if (copy_from_sockptr(p, src, len)) {
110 return ERR_PTR(-EFAULT);
116 static inline long strncpy_from_sockptr(char *dst, sockptr_t src, size_t count)
118 if (sockptr_is_kernel(src)) {
119 size_t len = min(strnlen(src.kernel, count - 1) + 1, count);
121 memcpy(dst, src.kernel, len);
124 return strncpy_from_user(dst, src.user, count);
127 #endif /* _LINUX_SOCKPTR_H */