diff mbox series

[v2] net/rose: Fix Use-After-Free in rose_ioctl

Message ID 20231206041332.GA5721@ubuntu (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [v2] net/rose: Fix Use-After-Free in rose_ioctl | expand

Checks

Context Check Description
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: 1115 this patch: 1115
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 1142 this patch: 1142
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 No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1142 this patch: 1142
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 10 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Hyunwoo Kim Dec. 6, 2023, 4:13 a.m. UTC
Because rose_ioctl() accesses sk->sk_receive_queue
without holding a sk->sk_receive_queue.lock, it can
cause a race with rose_accept().
A use-after-free for skb occurs with the following flow.
```
rose_ioctl() -> skb_peek()
rose_accept() -> skb_dequeue() -> kfree_skb()
```
Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.

Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
---
v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
---
 net/rose/af_rose.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Eric Dumazet Dec. 6, 2023, 10:33 a.m. UTC | #1
On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim <v4bel@theori.io> wrote:
>
> Because rose_ioctl() accesses sk->sk_receive_queue
> without holding a sk->sk_receive_queue.lock, it can
> cause a race with rose_accept().
> A use-after-free for skb occurs with the following flow.
> ```
> rose_ioctl() -> skb_peek()
> rose_accept() -> skb_dequeue() -> kfree_skb()
> ```
> Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
>

Please add a Fixes: tag

> Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
> ---
> v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
> ---
>  net/rose/af_rose.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
> index 0cc5a4e19900..841c238de222 100644
> --- a/net/rose/af_rose.c
> +++ b/net/rose/af_rose.c
> @@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
>                 struct sk_buff *skb;
>                 long amount = 0L;
>                 /* These two are safe on a single CPU system as only user tasks fiddle here */
> +               spin_lock(&sk->sk_receive_queue.lock);

You need interrupt safety here.

sk_receive_queue can be fed from interrupt, that would potentially deadlock.

>                 if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
>                         amount = skb->len;
> +               spin_unlock(&sk->sk_receive_queue.lock);
>                 return put_user(amount, (unsigned int __user *) argp);
>         }
>
> --
> 2.25.1
>
Hyunwoo Kim Dec. 6, 2023, 10:52 a.m. UTC | #2
Dear,

On Wed, Dec 06, 2023 at 11:33:15AM +0100, Eric Dumazet wrote:
> On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim <v4bel@theori.io> wrote:
> >
> > Because rose_ioctl() accesses sk->sk_receive_queue
> > without holding a sk->sk_receive_queue.lock, it can
> > cause a race with rose_accept().
> > A use-after-free for skb occurs with the following flow.
> > ```
> > rose_ioctl() -> skb_peek()
> > rose_accept() -> skb_dequeue() -> kfree_skb()
> > ```
> > Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
> >
> 
> Please add a Fixes: tag
> 
> > Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
> > ---
> > v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
> > ---
> >  net/rose/af_rose.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
> > index 0cc5a4e19900..841c238de222 100644
> > --- a/net/rose/af_rose.c
> > +++ b/net/rose/af_rose.c
> > @@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
> >                 struct sk_buff *skb;
> >                 long amount = 0L;
> >                 /* These two are safe on a single CPU system as only user tasks fiddle here */
> > +               spin_lock(&sk->sk_receive_queue.lock);
> 
> You need interrupt safety here.
> 
> sk_receive_queue can be fed from interrupt, that would potentially deadlock.

I want to change spin_lock to spin_lock_irqsave, is this okay?


Regards,
Hyunwoo Kim

> 
> >                 if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
> >                         amount = skb->len;
> > +               spin_unlock(&sk->sk_receive_queue.lock);
> >                 return put_user(amount, (unsigned int __user *) argp);
> >         }
> >
> > --
> > 2.25.1
> >
Eric Dumazet Dec. 6, 2023, 10:56 a.m. UTC | #3
On Wed, Dec 6, 2023 at 11:52 AM Hyunwoo Kim <v4bel@theori.io> wrote:
>
> Dear,
>
> On Wed, Dec 06, 2023 at 11:33:15AM +0100, Eric Dumazet wrote:
> > On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim <v4bel@theori.io> wrote:
> > >
> > > Because rose_ioctl() accesses sk->sk_receive_queue
> > > without holding a sk->sk_receive_queue.lock, it can
> > > cause a race with rose_accept().
> > > A use-after-free for skb occurs with the following flow.
> > > ```
> > > rose_ioctl() -> skb_peek()
> > > rose_accept() -> skb_dequeue() -> kfree_skb()
> > > ```
> > > Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
> > >
> >
> > Please add a Fixes: tag
> >
> > > Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
> > > ---
> > > v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
> > > ---
> > >  net/rose/af_rose.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
> > > index 0cc5a4e19900..841c238de222 100644
> > > --- a/net/rose/af_rose.c
> > > +++ b/net/rose/af_rose.c
> > > @@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
> > >                 struct sk_buff *skb;
> > >                 long amount = 0L;
> > >                 /* These two are safe on a single CPU system as only user tasks fiddle here */
> > > +               spin_lock(&sk->sk_receive_queue.lock);
> >
> > You need interrupt safety here.
> >
> > sk_receive_queue can be fed from interrupt, that would potentially deadlock.
>
> I want to change spin_lock to spin_lock_irqsave, is this okay?


Either spin_lock_irq() or spin_lock_irqsave() will work.

>
>
> Regards,
> Hyunwoo Kim
>
> >
> > >                 if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
> > >                         amount = skb->len;
> > > +               spin_unlock(&sk->sk_receive_queue.lock);
> > >                 return put_user(amount, (unsigned int __user *) argp);
> > >         }
> > >
> > > --
> > > 2.25.1
> > >
diff mbox series

Patch

diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 0cc5a4e19900..841c238de222 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -1316,8 +1316,10 @@  static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		struct sk_buff *skb;
 		long amount = 0L;
 		/* These two are safe on a single CPU system as only user tasks fiddle here */
+		spin_lock(&sk->sk_receive_queue.lock);
 		if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
 			amount = skb->len;
+		spin_unlock(&sk->sk_receive_queue.lock);
 		return put_user(amount, (unsigned int __user *) argp);
 	}