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[v5] af_unix: Read with MSG_PEEK loops if the first unread byte is OOB

Message ID 20240516231622.1545187-1-Rao.Shoaib@oracle.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series [v5] af_unix: Read with MSG_PEEK loops if the first unread byte is OOB | expand

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netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 926 this patch: 926
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: dhowells@redhat.com
netdev/build_clang success Errors and warnings before: 925 this patch: 925
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
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: 931 this patch: 931
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
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netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Shoaib Rao May 16, 2024, 11:16 p.m. UTC 
Read with MSG_PEEK flag loops if the first byte to read is an OOB byte.
commit 22dd70eb2c3d ("af_unix: Don't peek OOB data without MSG_OOB.")
addresses the loop issue but does not address the issue that no data
beyond OOB byte can be read.

>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c1.send(b'a', MSG_OOB)
1
>>> c1.send(b'b')
1
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'b'

>>> from socket import *
>>> c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
>>> c2.setsockopt(SOL_SOCKET, SO_OOBINLINE, 1)
>>> c1.send(b'a', MSG_OOB)
1
>>> c1.send(b'b')
1
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'a'
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'a'
>>> c2.recv(1, MSG_DONTWAIT)
b'a'
>>> c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
b'b'
>>>

Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Signed-off-by: Rao Shoaib <Rao.Shoaib@oracle.com>
---
 net/unix/af_unix.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

Comments

Paolo Abeni May 21, 2024, 11:11 a.m. UTC | #1 
On Thu, 2024-05-16 at 16:16 -0700, Rao Shoaib wrote:
> Read with MSG_PEEK flag loops if the first byte to read is an OOB byte.
> commit 22dd70eb2c3d ("af_unix: Don't peek OOB data without MSG_OOB.")
> addresses the loop issue but does not address the issue that no data
> beyond OOB byte can be read.
> 
> > > > from socket import *
> > > > c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
> > > > c1.send(b'a', MSG_OOB)
> 1
> > > > c1.send(b'b')
> 1
> > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> b'b'
> 
> > > > from socket import *
> > > > c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
> > > > c2.setsockopt(SOL_SOCKET, SO_OOBINLINE, 1)
> > > > c1.send(b'a', MSG_OOB)
> 1
> > > > c1.send(b'b')
> 1
> > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> b'a'
> > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> b'a'
> > > > c2.recv(1, MSG_DONTWAIT)
> b'a'
> > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> b'b'
> > > > 
> 
> Fixes: 314001f0bf92 ("af_unix: Add OOB support")
> Signed-off-by: Rao Shoaib <Rao.Shoaib@oracle.com>
> ---
>  net/unix/af_unix.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index fa906ec5e657..6e5ef44640ea 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -2612,19 +2612,19 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
>  		if (skb == u->oob_skb) {
>  			if (copied) {
>  				skb = NULL;
> -			} else if (sock_flag(sk, SOCK_URGINLINE)) {
> -				if (!(flags & MSG_PEEK)) {
> +			} else if (!(flags & MSG_PEEK)) {
> +				if (sock_flag(sk, SOCK_URGINLINE)) {
>  					WRITE_ONCE(u->oob_skb, NULL);
>  					consume_skb(skb);
> +				} else {
> +					skb_unlink(skb, &sk->sk_receive_queue);
> +					WRITE_ONCE(u->oob_skb, NULL);
> +					if (!WARN_ON_ONCE(skb_unref(skb)))
> +						kfree_skb(skb);
> +					skb = skb_peek(&sk->sk_receive_queue);
>  				}
> -			} else if (flags & MSG_PEEK) {
> -				skb = NULL;
> -			} else {
> -				skb_unlink(skb, &sk->sk_receive_queue);
> -				WRITE_ONCE(u->oob_skb, NULL);
> -				if (!WARN_ON_ONCE(skb_unref(skb)))
> -					kfree_skb(skb);
> -				skb = skb_peek(&sk->sk_receive_queue);
> +			} else if (!sock_flag(sk, SOCK_URGINLINE)) {
> +				skb = skb_peek_next(skb, &sk->sk_receive_queue);
>  			}
>  		}
>  	}

Does not apply cleanly anymore after commit 9841991a446c ("af_unix:
Update unix_sk(sk)->oob_skb under sk_receive_queue lock."), please
rebase, thanks!

Paolo
Kuniyuki Iwashima June 5, 2024, 9:21 p.m. UTC | #2 
From: Paolo Abeni <pabeni@redhat.com>
Date: Tue, 21 May 2024 13:11:52 +0200
> On Thu, 2024-05-16 at 16:16 -0700, Rao Shoaib wrote:
> > Read with MSG_PEEK flag loops if the first byte to read is an OOB byte.
> > commit 22dd70eb2c3d ("af_unix: Don't peek OOB data without MSG_OOB.")
> > addresses the loop issue but does not address the issue that no data
> > beyond OOB byte can be read.
> > 
> > > > > from socket import *
> > > > > c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
> > > > > c1.send(b'a', MSG_OOB)
> > 1
> > > > > c1.send(b'b')
> > 1
> > > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> > b'b'
> > 
> > > > > from socket import *
> > > > > c1, c2 = socketpair(AF_UNIX, SOCK_STREAM)
> > > > > c2.setsockopt(SOL_SOCKET, SO_OOBINLINE, 1)
> > > > > c1.send(b'a', MSG_OOB)
> > 1
> > > > > c1.send(b'b')
> > 1
> > > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> > b'a'
> > > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> > b'a'
> > > > > c2.recv(1, MSG_DONTWAIT)
> > b'a'
> > > > > c2.recv(1, MSG_PEEK | MSG_DONTWAIT)
> > b'b'
> > > > > 
> > 
> > Fixes: 314001f0bf92 ("af_unix: Add OOB support")
> > Signed-off-by: Rao Shoaib <Rao.Shoaib@oracle.com>
> > ---
> >  net/unix/af_unix.c | 20 ++++++++++----------
> >  1 file changed, 10 insertions(+), 10 deletions(-)
> > 
> > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> > index fa906ec5e657..6e5ef44640ea 100644
> > --- a/net/unix/af_unix.c
> > +++ b/net/unix/af_unix.c
> > @@ -2612,19 +2612,19 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
> >  		if (skb == u->oob_skb) {
> >  			if (copied) {
> >  				skb = NULL;
> > -			} else if (sock_flag(sk, SOCK_URGINLINE)) {
> > -				if (!(flags & MSG_PEEK)) {
> > +			} else if (!(flags & MSG_PEEK)) {
> > +				if (sock_flag(sk, SOCK_URGINLINE)) {
> >  					WRITE_ONCE(u->oob_skb, NULL);
> >  					consume_skb(skb);
> > +				} else {
> > +					skb_unlink(skb, &sk->sk_receive_queue);
> > +					WRITE_ONCE(u->oob_skb, NULL);
> > +					if (!WARN_ON_ONCE(skb_unref(skb)))
> > +						kfree_skb(skb);
> > +					skb = skb_peek(&sk->sk_receive_queue);
> >  				}
> > -			} else if (flags & MSG_PEEK) {
> > -				skb = NULL;
> > -			} else {
> > -				skb_unlink(skb, &sk->sk_receive_queue);
> > -				WRITE_ONCE(u->oob_skb, NULL);
> > -				if (!WARN_ON_ONCE(skb_unref(skb)))
> > -					kfree_skb(skb);
> > -				skb = skb_peek(&sk->sk_receive_queue);
> > +			} else if (!sock_flag(sk, SOCK_URGINLINE)) {
> > +				skb = skb_peek_next(skb, &sk->sk_receive_queue);
> >  			}
> >  		}
> >  	}
> 
> Does not apply cleanly anymore after commit 9841991a446c ("af_unix:
> Update unix_sk(sk)->oob_skb under sk_receive_queue lock."), please
> rebase, thanks!

Hi Rao,

Do you have time to respin v6 or do you mind if I rebase it and post v6 ?
I have some patches for net-next on top of this fix.

Thanks
diff mbox series

Patch

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index fa906ec5e657..6e5ef44640ea 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2612,19 +2612,19 @@  static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 		if (skb == u->oob_skb) {
 			if (copied) {
 				skb = NULL;
-			} else if (sock_flag(sk, SOCK_URGINLINE)) {
-				if (!(flags & MSG_PEEK)) {
+			} else if (!(flags & MSG_PEEK)) {
+				if (sock_flag(sk, SOCK_URGINLINE)) {
 					WRITE_ONCE(u->oob_skb, NULL);
 					consume_skb(skb);
+				} else {
+					skb_unlink(skb, &sk->sk_receive_queue);
+					WRITE_ONCE(u->oob_skb, NULL);
+					if (!WARN_ON_ONCE(skb_unref(skb)))
+						kfree_skb(skb);
+					skb = skb_peek(&sk->sk_receive_queue);
 				}
-			} else if (flags & MSG_PEEK) {
-				skb = NULL;
-			} else {
-				skb_unlink(skb, &sk->sk_receive_queue);
-				WRITE_ONCE(u->oob_skb, NULL);
-				if (!WARN_ON_ONCE(skb_unref(skb)))
-					kfree_skb(skb);
-				skb = skb_peek(&sk->sk_receive_queue);
+			} else if (!sock_flag(sk, SOCK_URGINLINE)) {
+				skb = skb_peek_next(skb, &sk->sk_receive_queue);
 			}
 		}
 	}