b24413180f560 (Greg Kroah-Hartman 2017-11-01 15:07:57 +0100 1) // SPDX-License-Identifier: GPL-2.0
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 2) #include <linux/bitops.h>
4d0e9df5e43db (Albert van der Linde 2020-10-15 20:13:50 -0700 3) #include <linux/fault-inject-usercopy.h>
76d6f06c36a3b (Marco Elver 2020-01-21 17:05:12 +0100 4) #include <linux/instrumented.h>
76d6f06c36a3b (Marco Elver 2020-01-21 17:05:12 +0100 5) #include <linux/uaccess.h>
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 6)
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 7) /* out-of-line parts */
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 8)
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 9) #ifndef INLINE_COPY_FROM_USER
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 10) unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 11) {
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 12) unsigned long res = n;
9c5f6908de03a (Al Viro 2017-06-29 21:39:54 -0400 13) might_fault();
4d0e9df5e43db (Albert van der Linde 2020-10-15 20:13:50 -0700 14) if (!should_fail_usercopy() && likely(access_ok(from, n))) {
76d6f06c36a3b (Marco Elver 2020-01-21 17:05:12 +0100 15) instrument_copy_from_user(to, from, n);
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 16) res = raw_copy_from_user(to, from, n);
9c5f6908de03a (Al Viro 2017-06-29 21:39:54 -0400 17) }
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 18) if (unlikely(res))
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 19) memset(to + (n - res), 0, res);
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 20) return res;
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 21) }
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 22) EXPORT_SYMBOL(_copy_from_user);
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 23) #endif
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 24)
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 25) #ifndef INLINE_COPY_TO_USER
a0e94598e6b6c (Christophe Leroy 2017-12-09 17:24:24 +0100 26) unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 27) {
9c5f6908de03a (Al Viro 2017-06-29 21:39:54 -0400 28) might_fault();
4d0e9df5e43db (Albert van der Linde 2020-10-15 20:13:50 -0700 29) if (should_fail_usercopy())
4d0e9df5e43db (Albert van der Linde 2020-10-15 20:13:50 -0700 30) return n;
96d4f267e40f9 (Linus Torvalds 2019-01-03 18:57:57 -0800 31) if (likely(access_ok(to, n))) {
76d6f06c36a3b (Marco Elver 2020-01-21 17:05:12 +0100 32) instrument_copy_to_user(to, from, n);
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 33) n = raw_copy_to_user(to, from, n);
9c5f6908de03a (Al Viro 2017-06-29 21:39:54 -0400 34) }
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 35) return n;
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 36) }
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 37) EXPORT_SYMBOL(_copy_to_user);
d597580d37377 (Al Viro 2017-03-20 21:56:06 -0400 38) #endif
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 39)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 40) /**
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 41) * check_zeroed_user: check if a userspace buffer only contains zero bytes
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 42) * @from: Source address, in userspace.
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 43) * @size: Size of buffer.
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 44) *
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 45) * This is effectively shorthand for "memchr_inv(from, 0, size) == NULL" for
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 46) * userspace addresses (and is more efficient because we don't care where the
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 47) * first non-zero byte is).
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 48) *
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 49) * Returns:
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 50) * * 0: There were non-zero bytes present in the buffer.
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 51) * * 1: The buffer was full of zero bytes.
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 52) * * -EFAULT: access to userspace failed.
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 53) */
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 54) int check_zeroed_user(const void __user *from, size_t size)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 55) {
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 56) unsigned long val;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 57) uintptr_t align = (uintptr_t) from % sizeof(unsigned long);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 58)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 59) if (unlikely(size == 0))
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 60) return 1;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 61)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 62) from -= align;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 63) size += align;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 64)
41cd780524674 (Christophe Leroy 2020-04-03 07:20:51 +0000 65) if (!user_read_access_begin(from, size))
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 66) return -EFAULT;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 67)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 68) unsafe_get_user(val, (unsigned long __user *) from, err_fault);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 69) if (align)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 70) val &= ~aligned_byte_mask(align);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 71)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 72) while (size > sizeof(unsigned long)) {
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 73) if (unlikely(val))
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 74) goto done;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 75)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 76) from += sizeof(unsigned long);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 77) size -= sizeof(unsigned long);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 78)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 79) unsafe_get_user(val, (unsigned long __user *) from, err_fault);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 80) }
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 81)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 82) if (size < sizeof(unsigned long))
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 83) val &= aligned_byte_mask(size);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 84)
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 85) done:
41cd780524674 (Christophe Leroy 2020-04-03 07:20:51 +0000 86) user_read_access_end();
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 87) return (val == 0);
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 88) err_fault:
41cd780524674 (Christophe Leroy 2020-04-03 07:20:51 +0000 89) user_read_access_end();
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 90) return -EFAULT;
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 91) }
f5a1a536fa148 (Aleksa Sarai 2019-10-01 11:10:52 +1000 92) EXPORT_SYMBOL(check_zeroed_user);
VisionFive2 Linux kernel
StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)
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