From: Philipp Stanner <pstanner@redhat.com>
To: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Stanislav Fomichev <sdf@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-ppp@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
Philipp Stanner <pstanner@redhat.com>,
Dave Airlie <airlied@redhat.com>
Subject: [PATCH v2] drivers/net/ppp: use standard array-copy-function
Date: Mon, 6 Nov 2023 10:16:00 +0100 [thread overview]
Message-ID: <20231106091559.14419-2-pstanner@redhat.com> (raw)
In ppp_generic.c, memdup_user() is utilized to copy a userspace array.
This is done without an overflow-check, which is, however, not critical
because the multiplicands are an unsigned short and struct sock_filter,
which is currently of size 8.
Regardless, string.h now provides memdup_array_user(), a wrapper for
copying userspace arrays in a standardized manner, which has the
advantage of making it more obvious to the reader that an array is being
copied.
The wrapper additionally performs an obligatory overflow check, saving
the reader the effort of analyzing the potential for overflow, and
making the code a bit more robust in case of future changes to the
multiplicands len * size.
Replace memdup_user() with memdup_array_user().
Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
Changes in v2:
- Rename the commit and rephrase its message completely so that it
becomes a) obvious that we're not fixing an actual overflow here and
b) emphasize that the goal is increasing readability. (Al Viro)
---
drivers/net/ppp/ppp_generic.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index a9beacd552cf..0193af2d31c9 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -570,8 +570,8 @@ static struct bpf_prog *get_filter(struct sock_fprog *uprog)
/* uprog->len is unsigned short, so no overflow here */
fprog.len = uprog->len;
- fprog.filter = memdup_user(uprog->filter,
- uprog->len * sizeof(struct sock_filter));
+ fprog.filter = memdup_array_user(uprog->filter,
+ uprog->len, sizeof(struct sock_filter));
if (IS_ERR(fprog.filter))
return ERR_CAST(fprog.filter);
--
2.41.0
next reply other threads:[~2023-11-06 9:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-06 9:16 Philipp Stanner [this message]
2023-11-08 9:50 ` [PATCH v2] drivers/net/ppp: use standard array-copy-function patchwork-bot+netdevbpf
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=20231106091559.14419-2-pstanner@redhat.com \
--to=pstanner@redhat.com \
--cc=airlied@redhat.com \
--cc=benjamin.tissoires@redhat.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=gregkh@linuxfoundation.org \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-ppp@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=sdf@google.com \
--cc=viro@zeniv.linux.org.uk \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).