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-rw-r--r--arch/x86/lib/usercopy.c103
-rw-r--r--arch/x86/lib/usercopy_32.c87
-rw-r--r--arch/x86/lib/usercopy_64.c49
3 files changed, 103 insertions, 136 deletions
diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
index 97be9cb54483..57252c928f56 100644
--- a/arch/x86/lib/usercopy.c
+++ b/arch/x86/lib/usercopy.c
@@ -7,6 +7,8 @@
7#include <linux/highmem.h> 7#include <linux/highmem.h>
8#include <linux/module.h> 8#include <linux/module.h>
9 9
10#include <asm/word-at-a-time.h>
11
10/* 12/*
11 * best effort, GUP based copy_from_user() that is NMI-safe 13 * best effort, GUP based copy_from_user() that is NMI-safe
12 */ 14 */
@@ -41,3 +43,104 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
41 return len; 43 return len;
42} 44}
43EXPORT_SYMBOL_GPL(copy_from_user_nmi); 45EXPORT_SYMBOL_GPL(copy_from_user_nmi);
46
47static inline unsigned long count_bytes(unsigned long mask)
48{
49 mask = (mask - 1) & ~mask;
50 mask >>= 7;
51 return count_masked_bytes(mask);
52}
53
54/*
55 * Do a strncpy, return length of string without final '\0'.
56 * 'count' is the user-supplied count (return 'count' if we
57 * hit it), 'max' is the address space maximum (and we return
58 * -EFAULT if we hit it).
59 */
60static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, long max)
61{
62 long res = 0;
63
64 /*
65 * Truncate 'max' to the user-specified limit, so that
66 * we only have one limit we need to check in the loop
67 */
68 if (max > count)
69 max = count;
70
71 while (max >= sizeof(unsigned long)) {
72 unsigned long c;
73
74 /* Fall back to byte-at-a-time if we get a page fault */
75 if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
76 break;
77 /* This can write a few bytes past the NUL character, but that's ok */
78 *(unsigned long *)(dst+res) = c;
79 c = has_zero(c);
80 if (c)
81 return res + count_bytes(c);
82 res += sizeof(unsigned long);
83 max -= sizeof(unsigned long);
84 }
85
86 while (max) {
87 char c;
88
89 if (unlikely(__get_user(c,src+res)))
90 return -EFAULT;
91 dst[res] = c;
92 if (!c)
93 return res;
94 res++;
95 max--;
96 }
97
98 /*
99 * Uhhuh. We hit 'max'. But was that the user-specified maximum
100 * too? If so, that's ok - we got as much as the user asked for.
101 */
102 if (res >= count)
103 return count;
104
105 /*
106 * Nope: we hit the address space limit, and we still had more
107 * characters the caller would have wanted. That's an EFAULT.
108 */
109 return -EFAULT;
110}
111
112/**
113 * strncpy_from_user: - Copy a NUL terminated string from userspace.
114 * @dst: Destination address, in kernel space. This buffer must be at
115 * least @count bytes long.
116 * @src: Source address, in user space.
117 * @count: Maximum number of bytes to copy, including the trailing NUL.
118 *
119 * Copies a NUL-terminated string from userspace to kernel space.
120 *
121 * On success, returns the length of the string (not including the trailing
122 * NUL).
123 *
124 * If access to userspace fails, returns -EFAULT (some data may have been
125 * copied).
126 *
127 * If @count is smaller than the length of the string, copies @count bytes
128 * and returns @count.
129 */
130long
131strncpy_from_user(char *dst, const char __user *src, long count)
132{
133 unsigned long max_addr, src_addr;
134
135 if (unlikely(count <= 0))
136 return 0;
137
138 max_addr = current_thread_info()->addr_limit.seg;
139 src_addr = (unsigned long)src;
140 if (likely(src_addr < max_addr)) {
141 unsigned long max = max_addr - src_addr;
142 return do_strncpy_from_user(dst, src, count, max);
143 }
144 return -EFAULT;
145}
146EXPORT_SYMBOL(strncpy_from_user);
diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c
index d9b094ca7aaa..ef2a6a5d78e3 100644
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -33,93 +33,6 @@ static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned lon
33 __movsl_is_ok((unsigned long)(a1), (unsigned long)(a2), (n)) 33 __movsl_is_ok((unsigned long)(a1), (unsigned long)(a2), (n))
34 34
35/* 35/*
36 * Copy a null terminated string from userspace.
37 */
38
39#define __do_strncpy_from_user(dst, src, count, res) \
40do { \
41 int __d0, __d1, __d2; \
42 might_fault(); \
43 __asm__ __volatile__( \
44 " testl %1,%1\n" \
45 " jz 2f\n" \
46 "0: lodsb\n" \
47 " stosb\n" \
48 " testb %%al,%%al\n" \
49 " jz 1f\n" \
50 " decl %1\n" \
51 " jnz 0b\n" \
52 "1: subl %1,%0\n" \
53 "2:\n" \
54 ".section .fixup,\"ax\"\n" \
55 "3: movl %5,%0\n" \
56 " jmp 2b\n" \
57 ".previous\n" \
58 _ASM_EXTABLE(0b,3b) \
59 : "=&d"(res), "=&c"(count), "=&a" (__d0), "=&S" (__d1), \
60 "=&D" (__d2) \
61 : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
62 : "memory"); \
63} while (0)
64
65/**
66 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
67 * @dst: Destination address, in kernel space. This buffer must be at
68 * least @count bytes long.
69 * @src: Source address, in user space.
70 * @count: Maximum number of bytes to copy, including the trailing NUL.
71 *
72 * Copies a NUL-terminated string from userspace to kernel space.
73 * Caller must check the specified block with access_ok() before calling
74 * this function.
75 *
76 * On success, returns the length of the string (not including the trailing
77 * NUL).
78 *
79 * If access to userspace fails, returns -EFAULT (some data may have been
80 * copied).
81 *
82 * If @count is smaller than the length of the string, copies @count bytes
83 * and returns @count.
84 */
85long
86__strncpy_from_user(char *dst, const char __user *src, long count)
87{
88 long res;
89 __do_strncpy_from_user(dst, src, count, res);
90 return res;
91}
92EXPORT_SYMBOL(__strncpy_from_user);
93
94/**
95 * strncpy_from_user: - Copy a NUL terminated string from userspace.
96 * @dst: Destination address, in kernel space. This buffer must be at
97 * least @count bytes long.
98 * @src: Source address, in user space.
99 * @count: Maximum number of bytes to copy, including the trailing NUL.
100 *
101 * Copies a NUL-terminated string from userspace to kernel space.
102 *
103 * On success, returns the length of the string (not including the trailing
104 * NUL).
105 *
106 * If access to userspace fails, returns -EFAULT (some data may have been
107 * copied).
108 *
109 * If @count is smaller than the length of the string, copies @count bytes
110 * and returns @count.
111 */
112long
113strncpy_from_user(char *dst, const char __user *src, long count)
114{
115 long res = -EFAULT;
116 if (access_ok(VERIFY_READ, src, 1))
117 __do_strncpy_from_user(dst, src, count, res);
118 return res;
119}
120EXPORT_SYMBOL(strncpy_from_user);
121
122/*
123 * Zero Userspace 36 * Zero Userspace
124 */ 37 */
125 38
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index b7c2849ffb66..0d0326f388c0 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -9,55 +9,6 @@
9#include <asm/uaccess.h> 9#include <asm/uaccess.h>
10 10
11/* 11/*
12 * Copy a null terminated string from userspace.
13 */
14
15#define __do_strncpy_from_user(dst,src,count,res) \
16do { \
17 long __d0, __d1, __d2; \
18 might_fault(); \
19 __asm__ __volatile__( \
20 " testq %1,%1\n" \
21 " jz 2f\n" \
22 "0: lodsb\n" \
23 " stosb\n" \
24 " testb %%al,%%al\n" \
25 " jz 1f\n" \
26 " decq %1\n" \
27 " jnz 0b\n" \
28 "1: subq %1,%0\n" \
29 "2:\n" \
30 ".section .fixup,\"ax\"\n" \
31 "3: movq %5,%0\n" \
32 " jmp 2b\n" \
33 ".previous\n" \
34 _ASM_EXTABLE(0b,3b) \
35 : "=&r"(res), "=&c"(count), "=&a" (__d0), "=&S" (__d1), \
36 "=&D" (__d2) \
37 : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
38 : "memory"); \
39} while (0)
40
41long
42__strncpy_from_user(char *dst, const char __user *src, long count)
43{
44 long res;
45 __do_strncpy_from_user(dst, src, count, res);
46 return res;
47}
48EXPORT_SYMBOL(__strncpy_from_user);
49
50long
51strncpy_from_user(char *dst, const char __user *src, long count)
52{
53 long res = -EFAULT;
54 if (access_ok(VERIFY_READ, src, 1))
55 return __strncpy_from_user(dst, src, count);
56 return res;
57}
58EXPORT_SYMBOL(strncpy_from_user);
59
60/*
61 * Zero Userspace 12 * Zero Userspace
62 */ 13 */
63 14
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-04 08:09:52 -0500