include/linux/bpfptr.h

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /* A pointer that can point to either kernel or userspace memory. */
0003 #ifndef _LINUX_BPFPTR_H
0004 #define _LINUX_BPFPTR_H
0005
0006 #include <linux/mm.h>
0007 #include <linux/sockptr.h>
0008
0009 typedef sockptr_t bpfptr_t;
0010
0011 static inline bool bpfptr_is_kernel(bpfptr_t bpfptr)
0012 {
0013     return bpfptr.is_kernel;
0014 }
0015
0016 static inline bpfptr_t KERNEL_BPFPTR(void *p)
0017 {
0018     return (bpfptr_t) { .kernel = p, .is_kernel = true };
0019 }
0020
0021 static inline bpfptr_t USER_BPFPTR(void __user *p)
0022 {
0023     return (bpfptr_t) { .user = p };
0024 }
0025
0026 static inline bpfptr_t make_bpfptr(u64 addr, bool is_kernel)
0027 {
0028     if (is_kernel)
0029         return KERNEL_BPFPTR((void*) (uintptr_t) addr);
0030     else
0031         return USER_BPFPTR(u64_to_user_ptr(addr));
0032 }
0033
0034 static inline bool bpfptr_is_null(bpfptr_t bpfptr)
0035 {
0036     if (bpfptr_is_kernel(bpfptr))
0037         return !bpfptr.kernel;
0038     return !bpfptr.user;
0039 }
0040
0041 static inline void bpfptr_add(bpfptr_t *bpfptr, size_t val)
0042 {
0043     if (bpfptr_is_kernel(*bpfptr))
0044         bpfptr->kernel += val;
0045     else
0046         bpfptr->user += val;
0047 }
0048
0049 static inline int copy_from_bpfptr_offset(void *dst, bpfptr_t src,
0050                       size_t offset, size_t size)
0051 {
0052     if (!bpfptr_is_kernel(src))
0053         return copy_from_user(dst, src.user + offset, size);
0054     return copy_from_kernel_nofault(dst, src.kernel + offset, size);
0055 }
0056
0057 static inline int copy_from_bpfptr(void *dst, bpfptr_t src, size_t size)
0058 {
0059     return copy_from_bpfptr_offset(dst, src, 0, size);
0060 }
0061
0062 static inline int copy_to_bpfptr_offset(bpfptr_t dst, size_t offset,
0063                     const void *src, size_t size)
0064 {
0065     return copy_to_sockptr_offset((sockptr_t) dst, offset, src, size);
0066 }
0067
0068 static inline void *kvmemdup_bpfptr(bpfptr_t src, size_t len)
0069 {
0070     void *p = kvmalloc(len, GFP_USER | __GFP_NOWARN);
0071
0072     if (!p)
0073         return ERR_PTR(-ENOMEM);
0074     if (copy_from_bpfptr(p, src, len)) {
0075         kvfree(p);
0076         return ERR_PTR(-EFAULT);
0077     }
0078     return p;
0079 }
0080
0081 static inline long strncpy_from_bpfptr(char *dst, bpfptr_t src, size_t count)
0082 {
0083     if (bpfptr_is_kernel(src))
0084         return strncpy_from_kernel_nofault(dst, src.kernel, count);
0085     return strncpy_from_user(dst, src.user, count);
0086 }
0087
0088 #endif /* _LINUX_BPFPTR_H */