[v2] io_uring: Initial support for {s,g}etsockopt commands

[PATCH v2 7/8] io_uring/cmd: BPF hook for getsockopt cmd

Posted by Breno Leitao 2 years, 1 month ago

Add BPF hooks support for getsockopts io_uring command. So, bpf cgroups
programs can run when SOCKET_URING_OP_GETSOCKOPT command is called.

This implementation follows a similar approach to what
__sys_getsockopt() does, but, using USER_SOCKPTR() for optval instead of
kernel pointer.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 io_uring/uring_cmd.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index dbba005a7290..3693e5779229 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -5,6 +5,8 @@
 #include <linux/io_uring.h>
 #include <linux/security.h>
 #include <linux/nospec.h>
+#include <linux/compat.h>
+#include <linux/bpf-cgroup.h>
 
 #include <uapi/linux/io_uring.h>
 #include <uapi/asm-generic/ioctls.h>
@@ -179,17 +181,23 @@ static inline int io_uring_cmd_getsockopt(struct socket *sock,
 	if (err)
 		return err;
 
-	if (level == SOL_SOCKET) {
+	err = -EOPNOTSUPP;
+	if (level == SOL_SOCKET)
 		err = sk_getsockopt(sock->sk, level, optname,
 				    USER_SOCKPTR(optval),
 				    KERNEL_SOCKPTR(&optlen));
-		if (err)
-			return err;
 
+	if (!in_compat_syscall())
+		err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level,
+						     optname,
+						     USER_SOCKPTR(optval),
+						     KERNEL_SOCKPTR(&optlen),
+						     optlen, err);
+
+	if (!err)
 		return optlen;
-	}
 
-	return -EOPNOTSUPP;
+	return err;
 }
 
 static inline int io_uring_cmd_setsockopt(struct socket *sock,
-- 
2.34.1

Re: [PATCH v2 7/8] io_uring/cmd: BPF hook for getsockopt cmd

Posted by Gabriel Krisman Bertazi 2 years, 1 month ago

Breno Leitao <leitao@debian.org> writes:

> Add BPF hooks support for getsockopts io_uring command. So, bpf cgroups
> programs can run when SOCKET_URING_OP_GETSOCKOPT command is called.
>
> This implementation follows a similar approach to what
> __sys_getsockopt() does, but, using USER_SOCKPTR() for optval instead of
> kernel pointer.
>
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  io_uring/uring_cmd.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
> index dbba005a7290..3693e5779229 100644
> --- a/io_uring/uring_cmd.c
> +++ b/io_uring/uring_cmd.c
> @@ -5,6 +5,8 @@
>  #include <linux/io_uring.h>
>  #include <linux/security.h>
>  #include <linux/nospec.h>
> +#include <linux/compat.h>
> +#include <linux/bpf-cgroup.h>
>  
>  #include <uapi/linux/io_uring.h>
>  #include <uapi/asm-generic/ioctls.h>
> @@ -179,17 +181,23 @@ static inline int io_uring_cmd_getsockopt(struct socket *sock,
>  	if (err)
>  		return err;
>  
> -	if (level == SOL_SOCKET) {
> +	err = -EOPNOTSUPP;
> +	if (level == SOL_SOCKET)
>  		err = sk_getsockopt(sock->sk, level, optname,
>  				    USER_SOCKPTR(optval),
>  				    KERNEL_SOCKPTR(&optlen));
> -		if (err)
> -			return err;
>  
> +	if (!in_compat_syscall())
> +		err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level,
> +						     optname,
> +						     USER_SOCKPTR(optval),
> +						     KERNEL_SOCKPTR(&optlen),
> +						     optlen, err);

I'm not sure if it makes sense to use in_compat_syscall() here.  Can't
this be invoked in a ring with ctx->compat set, but from outside a
compat syscall context (i.e. from sqpoll or even a !compat
io_uring_enter syscall)? I suspect you might need to check ctx->compact
instead, but I'm not sure. Did you consider that?

> +
> +	if (!err)
>  		return optlen;
> -	}
>  
> -	return -EOPNOTSUPP;
> +	return err;
>  }
>  
>  static inline int io_uring_cmd_setsockopt(struct socket *sock,

-- 
Gabriel Krisman Bertazi

Re: [PATCH v2 7/8] io_uring/cmd: BPF hook for getsockopt cmd

Posted by Breno Leitao 2 years, 1 month ago

Hello Gabriel,

On Wed, Aug 09, 2023 at 12:46:27PM -0400, Gabriel Krisman Bertazi wrote:
> Breno Leitao <leitao@debian.org> writes:
> 
> > Add BPF hooks support for getsockopts io_uring command. So, bpf cgroups
> > programs can run when SOCKET_URING_OP_GETSOCKOPT command is called.
> >
> > This implementation follows a similar approach to what
> > __sys_getsockopt() does, but, using USER_SOCKPTR() for optval instead of
> > kernel pointer.
> >
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> >  io_uring/uring_cmd.c | 18 +++++++++++++-----
> >  1 file changed, 13 insertions(+), 5 deletions(-)
> >
> > diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
> > index dbba005a7290..3693e5779229 100644
> > --- a/io_uring/uring_cmd.c
> > +++ b/io_uring/uring_cmd.c
> > @@ -5,6 +5,8 @@
> >  #include <linux/io_uring.h>
> >  #include <linux/security.h>
> >  #include <linux/nospec.h>
> > +#include <linux/compat.h>
> > +#include <linux/bpf-cgroup.h>
> >  
> >  #include <uapi/linux/io_uring.h>
> >  #include <uapi/asm-generic/ioctls.h>
> > @@ -179,17 +181,23 @@ static inline int io_uring_cmd_getsockopt(struct socket *sock,
> >  	if (err)
> >  		return err;
> >  
> > -	if (level == SOL_SOCKET) {
> > +	err = -EOPNOTSUPP;
> > +	if (level == SOL_SOCKET)
> >  		err = sk_getsockopt(sock->sk, level, optname,
> >  				    USER_SOCKPTR(optval),
> >  				    KERNEL_SOCKPTR(&optlen));
> > -		if (err)
> > -			return err;
> >  
> > +	if (!in_compat_syscall())
> > +		err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level,
> > +						     optname,
> > +						     USER_SOCKPTR(optval),
> > +						     KERNEL_SOCKPTR(&optlen),
> > +						     optlen, err);
> 
> I'm not sure if it makes sense to use in_compat_syscall() here.  Can't
> this be invoked in a ring with ctx->compat set, but from outside a
> compat syscall context (i.e. from sqpoll or even a !compat
> io_uring_enter syscall)? I suspect you might need to check ctx->compact
> instead, but I'm not sure. Did you consider that?

I think that checking ctx->compat seems to be the right thing to do. I
will update.