Messages in this thread Patch in this message | | | From | David Laight <> | Subject | [PATCH 2/3] Use _copy_from_user() to read SG iovec array. | Date | Fri, 24 Jan 2020 15:46:00 +0000 |
| |
The code has either just validated that the size fits in a caller supplied fixed size buffer or has used kmalloc() to allocate a buffer. So avoid the non-trivial cost of the HARDENED_USERCOPY checks by calling _copy_from_user() instead of copy_from_user().
Signed-off-by: David Laight <david.laight@aculab.com> --- fs/read_write.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/read_write.c b/fs/read_write.c index 441d9ca..0241d68 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -795,7 +795,7 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, goto out; } } - if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { + if (_copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { ret = -EFAULT; goto out; } -- 1.8.1.2 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
| |