include/linux/bpfptr.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /* A pointer that can point to either kernel or userspace memory. */
   3 #ifndef _LINUX_BPFPTR_H
   4 #define _LINUX_BPFPTR_H
   5
   6 #include <linux/mm.h>
   7 #include <linux/sockptr.h>
   8
   9 typedef sockptr_t bpfptr_t;
  10
  11 static inline bool bpfptr_is_kernel(bpfptr_t bpfptr)
  12 {
  13         return bpfptr.is_kernel;
  14 }
  15
  16 static inline bpfptr_t KERNEL_BPFPTR(void *p)
  17 {
  18         return (bpfptr_t) { .kernel = p, .is_kernel = true };
  19 }
  20
  21 static inline bpfptr_t USER_BPFPTR(void __user *p)
  22 {
  23         return (bpfptr_t) { .user = p };
  24 }
  25
  26 static inline bpfptr_t make_bpfptr(u64 addr, bool is_kernel)
  27 {
  28         if (is_kernel)
  29                 return KERNEL_BPFPTR((void*) (uintptr_t) addr);
  30         else
  31                 return USER_BPFPTR(u64_to_user_ptr(addr));
  32 }
  33
  34 static inline bool bpfptr_is_null(bpfptr_t bpfptr)
  35 {
  36         if (bpfptr_is_kernel(bpfptr))
  37                 return !bpfptr.kernel;
  38         return !bpfptr.user;
  39 }
  40
  41 static inline void bpfptr_add(bpfptr_t *bpfptr, size_t val)
  42 {
  43         if (bpfptr_is_kernel(*bpfptr))
  44                 bpfptr->kernel += val;
  45         else
  46                 bpfptr->user += val;
  47 }
  48
  49 static inline int copy_from_bpfptr_offset(void *dst, bpfptr_t src,
  50                                           size_t offset, size_t size)
  51 {
  52         if (!bpfptr_is_kernel(src))
  53                 return copy_from_user(dst, src.user + offset, size);
  54         return copy_from_kernel_nofault(dst, src.kernel + offset, size);
  55 }
  56
  57 static inline int copy_from_bpfptr(void *dst, bpfptr_t src, size_t size)
  58 {
  59         return copy_from_bpfptr_offset(dst, src, 0, size);
  60 }
  61
  62 static inline int copy_to_bpfptr_offset(bpfptr_t dst, size_t offset,
  63                                         const void *src, size_t size)
  64 {
  65         return copy_to_sockptr_offset((sockptr_t) dst, offset, src, size);
  66 }
  67
  68 static inline void *kvmemdup_bpfptr_noprof(bpfptr_t src, size_t len)
  69 {
  70         void *p = kvmalloc_noprof(len, GFP_USER | __GFP_NOWARN);
  71
  72         if (!p)
  73                 return ERR_PTR(-ENOMEM);
  74         if (copy_from_bpfptr(p, src, len)) {
  75                 kvfree(p);
  76                 return ERR_PTR(-EFAULT);
  77         }
  78         return p;
  79 }
  80 #define kvmemdup_bpfptr(...)    alloc_hooks(kvmemdup_bpfptr_noprof(__VA_ARGS__))
  81
  82 static inline long strncpy_from_bpfptr(char *dst, bpfptr_t src, size_t count)
  83 {
  84         if (bpfptr_is_kernel(src))
  85                 return strncpy_from_kernel_nofault(dst, src.kernel, count);
  86         return strncpy_from_user(dst, src.user, count);
  87 }
  88
  89 #endif /* _LINUX_BPFPTR_H */