All of lore.kernel.org
 help / color / mirror / Atom feed
From: David Laight <david.laight.linux@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: David Laight <david.laight.linux@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jens Axboe <axboe@kernel.dk>, David Howells <dhowells@redhat.com>,
	Matthew Wilcox <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH next 1/3] iov: Remove access_ok() from import_iovec()
Date: Fri, 21 Mar 2025 22:45:55 +0000	[thread overview]
Message-ID: <20250321224557.3847-2-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20250321224557.3847-1-david.laight.linux@gmail.com>

There is no point checking the validity of the user address when reading
the iovec[] from usespace.
It is checked again before the user copy itself.
Added in 09fc68dc66f75 (iov_iter: saner checks on copyin/copyout)

Signed-off-by: David Laight <david.laight.linux@gmail.com>
---
 lib/iov_iter.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 65f550cb5081..623ec43e049a 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1471,13 +1471,6 @@ ssize_t __import_iovec(int type, const struct iovec __user *uvec,
 	for (seg = 0; seg < nr_segs; seg++) {
 		ssize_t len = (ssize_t)iov[seg].iov_len;
 
-		if (!access_ok(iov[seg].iov_base, len)) {
-			if (iov != *iovp)
-				kfree(iov);
-			*iovp = NULL;
-			return -EFAULT;
-		}
-
 		if (len > MAX_RW_COUNT - total_len) {
 			len = MAX_RW_COUNT - total_len;
 			iov[seg].iov_len = len;
@@ -1528,8 +1521,6 @@ int import_ubuf(int rw, void __user *buf, size_t len, struct iov_iter *i)
 {
 	if (len > MAX_RW_COUNT)
 		len = MAX_RW_COUNT;
-	if (unlikely(!access_ok(buf, len)))
-		return -EFAULT;
 
 	iov_iter_ubuf(i, rw, buf, len);
 	return 0;
-- 
2.39.5


  reply	other threads:[~2025-03-21 22:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-21 22:45 [PATCH next 0/3] iov: Optimise user copies David Laight
2025-03-21 22:45 ` David Laight [this message]
2025-03-21 22:45 ` [PATCH next 2/3] iov: Use masked user accesses David Laight
2025-03-21 22:45 ` [PATCH next 3/3] iov: Optimise __import_iovec_ubuf() David Laight
2025-03-21 23:35 ` [PATCH next 0/3] iov: Optimise user copies Linus Torvalds
2025-03-22 10:08   ` David Laight
2025-03-22 22:37   ` David Laight
2025-03-29 11:31   ` David Laight
2025-03-22 14:36 ` Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250321224557.3847-2-david.laight.linux@gmail.com \
    --to=david.laight.linux@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=axboe@kernel.dk \
    --cc=dhowells@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@zeniv.linux.org.uk \
    --cc=willy@infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.