diff mbox series

[net,2/2] net/ieee802154: don't warn zero-sized raw_sendmsg()

Message ID 20221005014750.3685555-2-aahringo@redhat.com (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series [net,1/2] Revert "net/ieee802154: reject zero-sized raw_sendmsg()" | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers fail 3 blamed authors not CCed: sdf@google.com ast@kernel.org shaozhengchao@huawei.com; 5 maintainers not CCed: sdf@google.com ast@kernel.org alex.aring@gmail.com bpf@vger.kernel.org shaozhengchao@huawei.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 10 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Alexander Aring Oct. 5, 2022, 1:47 a.m. UTC 
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

syzbot is hitting skb_assert_len() warning at __dev_queue_xmit() [1],
for PF_IEEE802154 socket's zero-sized raw_sendmsg() request is hitting
__dev_queue_xmit() with skb->len == 0.

Since PF_IEEE802154 socket's zero-sized raw_sendmsg() request was
able to return 0, don't call __dev_queue_xmit() if packet length is 0.

  ----------
  #include <sys/socket.h>
  #include <netinet/in.h>

  int main(int argc, char *argv[])
  {
    struct sockaddr_in addr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_LOOPBACK) };
    struct iovec iov = { };
    struct msghdr hdr = { .msg_name = &addr, .msg_namelen = sizeof(addr), .msg_iov = &iov, .msg_iovlen = 1 };
    sendmsg(socket(PF_IEEE802154, SOCK_RAW, 0), &hdr, 0);
    return 0;
  }
  ----------

Note that this might be a sign that commit fd1894224407c484 ("bpf: Don't
redirect packets with invalid pkt_len") should be reverted, for
skb->len == 0 was acceptable for at least PF_IEEE802154 socket.

Link: https://syzkaller.appspot.com/bug?extid=5ea725c25d06fb9114c4 [1]
Reported-by: syzbot <syzbot+5ea725c25d06fb9114c4@syzkaller.appspotmail.com>
Fixes: fd1894224407c484 ("bpf: Don't redirect packets with invalid pkt_len")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 net/ieee802154/socket.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Stefan Schmidt Oct. 5, 2022, 10:57 a.m. UTC | #1 
Hello.

On 05.10.22 03:47, Alexander Aring wrote:
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> 
> syzbot is hitting skb_assert_len() warning at __dev_queue_xmit() [1],
> for PF_IEEE802154 socket's zero-sized raw_sendmsg() request is hitting
> __dev_queue_xmit() with skb->len == 0.
> 
> Since PF_IEEE802154 socket's zero-sized raw_sendmsg() request was
> able to return 0, don't call __dev_queue_xmit() if packet length is 0.
> 
>    ----------
>    #include <sys/socket.h>
>    #include <netinet/in.h>
> 
>    int main(int argc, char *argv[])
>    {
>      struct sockaddr_in addr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_LOOPBACK) };
>      struct iovec iov = { };
>      struct msghdr hdr = { .msg_name = &addr, .msg_namelen = sizeof(addr), .msg_iov = &iov, .msg_iovlen = 1 };
>      sendmsg(socket(PF_IEEE802154, SOCK_RAW, 0), &hdr, 0);
>      return 0;
>    }
>    ----------
> 
> Note that this might be a sign that commit fd1894224407c484 ("bpf: Don't
> redirect packets with invalid pkt_len") should be reverted, for
> skb->len == 0 was acceptable for at least PF_IEEE802154 socket.
> 
> Link: https://syzkaller.appspot.com/bug?extid=5ea725c25d06fb9114c4 [1]
> Reported-by: syzbot <syzbot+5ea725c25d06fb9114c4@syzkaller.appspotmail.com>
> Fixes: fd1894224407c484 ("bpf: Don't redirect packets with invalid pkt_len")
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Signed-off-by: Alexander Aring <aahringo@redhat.com>
> ---
>   net/ieee802154/socket.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c
> index 7889e1ef7fad..6e55fae4c686 100644
> --- a/net/ieee802154/socket.c
> +++ b/net/ieee802154/socket.c
> @@ -272,6 +272,10 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
>   		err = -EMSGSIZE;
>   		goto out_dev;
>   	}
> +	if (!size) {
> +		err = 0;
> +		goto out_dev;
> +	}
>   
>   	hlen = LL_RESERVED_SPACE(dev);
>   	tlen = dev->needed_tailroom;

This patch has been applied to the wpan tree and will be
part of the next pull request to net. Thanks!

regards
Stefan Schmidt
diff mbox series

Patch

diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c
index 7889e1ef7fad..6e55fae4c686 100644
--- a/net/ieee802154/socket.c
+++ b/net/ieee802154/socket.c
@@ -272,6 +272,10 @@  static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 		err = -EMSGSIZE;
 		goto out_dev;
 	}
+	if (!size) {
+		err = 0;
+		goto out_dev;
+	}
 
 	hlen = LL_RESERVED_SPACE(dev);
 	tlen = dev->needed_tailroom;