From: David Laight <David.Laight@ACULAB.COM>
To: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>
Subject: [PATCH 2/3] Use _copy_from_user() to read SG iovec array.
Date: Fri, 24 Jan 2020 15:46:00 +0000 [thread overview]
Message-ID: <04fbf8632f83496d819f27bb353dbf39@AcuMS.aculab.com> (raw)
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
-
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reply other threads:[~2020-01-24 15:46 UTC|newest]
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