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* [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere
@ 2022-04-19 22:22 Stanislav Fomichev
  2022-04-20 22:04 ` Andrii Nakryiko
  0 siblings, 1 reply; 5+ messages in thread
From: Stanislav Fomichev @ 2022-04-19 22:22 UTC (permalink / raw)
  To: netdev, bpf; +Cc: ast, daniel, andrii, Stanislav Fomichev

Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
use it everywhere. check_return_code already enforces sane
return ranges for all cgroup types. (only egress and bind hooks have
uncanonical return ranges, the rest is using [0, 1])

No functional changes.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 include/linux/bpf-cgroup.h |  8 ++---
 kernel/bpf/cgroup.c        | 70 ++++++++++++--------------------------
 2 files changed, 24 insertions(+), 54 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 88a51b242adc..669d96d074ad 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -225,24 +225,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
 
 #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype)				       \
 ({									       \
-	u32 __unused_flags;						       \
 	int __ret = 0;							       \
 	if (cgroup_bpf_enabled(atype))					       \
 		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
-							  NULL,		       \
-							  &__unused_flags);    \
+							  NULL, NULL);	       \
 	__ret;								       \
 })
 
 #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx)		       \
 ({									       \
-	u32 __unused_flags;						       \
 	int __ret = 0;							       \
 	if (cgroup_bpf_enabled(atype))	{				       \
 		lock_sock(sk);						       \
 		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
-							  t_ctx,	       \
-							  &__unused_flags);    \
+							  t_ctx, NULL);	       \
 		release_sock(sk);					       \
 	}								       \
 	__ret;								       \
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 0cb6211fcb58..f61eca32c747 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -25,50 +25,18 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
 /* __always_inline is necessary to prevent indirect call through run_prog
  * function pointer.
  */
-static __always_inline int
-bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
-			    enum cgroup_bpf_attach_type atype,
-			    const void *ctx, bpf_prog_run_fn run_prog,
-			    int retval, u32 *ret_flags)
-{
-	const struct bpf_prog_array_item *item;
-	const struct bpf_prog *prog;
-	const struct bpf_prog_array *array;
-	struct bpf_run_ctx *old_run_ctx;
-	struct bpf_cg_run_ctx run_ctx;
-	u32 func_ret;
-
-	run_ctx.retval = retval;
-	migrate_disable();
-	rcu_read_lock();
-	array = rcu_dereference(cgrp->effective[atype]);
-	item = &array->items[0];
-	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
-	while ((prog = READ_ONCE(item->prog))) {
-		run_ctx.prog_item = item;
-		func_ret = run_prog(prog, ctx);
-		if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
-			run_ctx.retval = -EPERM;
-		*(ret_flags) |= (func_ret >> 1);
-		item++;
-	}
-	bpf_reset_run_ctx(old_run_ctx);
-	rcu_read_unlock();
-	migrate_enable();
-	return run_ctx.retval;
-}
-
 static __always_inline int
 bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
 		      enum cgroup_bpf_attach_type atype,
 		      const void *ctx, bpf_prog_run_fn run_prog,
-		      int retval)
+		      int retval, u32 *ret_flags)
 {
 	const struct bpf_prog_array_item *item;
 	const struct bpf_prog *prog;
 	const struct bpf_prog_array *array;
 	struct bpf_run_ctx *old_run_ctx;
 	struct bpf_cg_run_ctx run_ctx;
+	u32 func_ret;
 
 	run_ctx.retval = retval;
 	migrate_disable();
@@ -78,8 +46,11 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
 	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
 	while ((prog = READ_ONCE(item->prog))) {
 		run_ctx.prog_item = item;
-		if (!run_prog(prog, ctx) && !IS_ERR_VALUE((long)run_ctx.retval))
+		func_ret = run_prog(prog, ctx);
+		if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
 			run_ctx.retval = -EPERM;
+		if (ret_flags)
+			*(ret_flags) |= (func_ret >> 1);
 		item++;
 	}
 	bpf_reset_run_ctx(old_run_ctx);
@@ -1144,9 +1115,8 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk,
 		u32 flags = 0;
 		bool cn;
 
-		ret = bpf_prog_run_array_cg_flags(
-			&cgrp->bpf, atype,
-			skb, __bpf_prog_run_save_cb, 0, &flags);
+		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb,
+					    __bpf_prog_run_save_cb, 0, &flags);
 
 		/* Return values of CGROUP EGRESS BPF programs are:
 		 *   0: drop packet
@@ -1172,7 +1142,8 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk,
 			ret = (cn ? NET_XMIT_DROP : ret);
 	} else {
 		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype,
-					    skb, __bpf_prog_run_save_cb, 0);
+					    skb, __bpf_prog_run_save_cb, 0,
+					    NULL);
 		if (ret && !IS_ERR_VALUE((long)ret))
 			ret = -EFAULT;
 	}
@@ -1202,7 +1173,8 @@ int __cgroup_bpf_run_filter_sk(struct sock *sk,
 {
 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
 
-	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0);
+	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0,
+				     NULL);
 }
 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
 
@@ -1247,8 +1219,8 @@ int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 	}
 
 	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
-	return bpf_prog_run_array_cg_flags(&cgrp->bpf, atype,
-					   &ctx, bpf_prog_run, 0, flags);
+	return bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run,
+				     0, flags);
 }
 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);
 
@@ -1275,7 +1247,7 @@ int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
 	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
 
 	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run,
-				     0);
+				     0, NULL);
 }
 EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);
 
@@ -1292,7 +1264,8 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
 
 	rcu_read_lock();
 	cgrp = task_dfl_cgroup(current);
-	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+				    NULL);
 	rcu_read_unlock();
 
 	return ret;
@@ -1457,7 +1430,8 @@ int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
 
 	rcu_read_lock();
 	cgrp = task_dfl_cgroup(current);
-	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+				    NULL);
 	rcu_read_unlock();
 
 	kfree(ctx.cur_val);
@@ -1550,7 +1524,7 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 
 	lock_sock(sk);
 	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT,
-				    &ctx, bpf_prog_run, 0);
+				    &ctx, bpf_prog_run, 0, NULL);
 	release_sock(sk);
 
 	if (ret)
@@ -1650,7 +1624,7 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 
 	lock_sock(sk);
 	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
-				    &ctx, bpf_prog_run, retval);
+				    &ctx, bpf_prog_run, retval, NULL);
 	release_sock(sk);
 
 	if (ret < 0)
@@ -1699,7 +1673,7 @@ int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
 	 */
 
 	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
-				    &ctx, bpf_prog_run, retval);
+				    &ctx, bpf_prog_run, retval, NULL);
 	if (ret < 0)
 		return ret;
 
-- 
2.36.0.rc0.470.gd361397f0d-goog


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere
  2022-04-19 22:22 [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere Stanislav Fomichev
@ 2022-04-20 22:04 ` Andrii Nakryiko
  2022-04-20 22:30   ` Stanislav Fomichev
  0 siblings, 1 reply; 5+ messages in thread
From: Andrii Nakryiko @ 2022-04-20 22:04 UTC (permalink / raw)
  To: Stanislav Fomichev
  Cc: Networking, bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko

On Tue, Apr 19, 2022 at 3:23 PM Stanislav Fomichev <sdf@google.com> wrote:
>
> Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
> use it everywhere. check_return_code already enforces sane
> return ranges for all cgroup types. (only egress and bind hooks have
> uncanonical return ranges, the rest is using [0, 1])
>
> No functional changes.
>
> Suggested-by: Alexei Starovoitov <ast@kernel.org>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
> ---
>  include/linux/bpf-cgroup.h |  8 ++---
>  kernel/bpf/cgroup.c        | 70 ++++++++++++--------------------------
>  2 files changed, 24 insertions(+), 54 deletions(-)
>
> diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
> index 88a51b242adc..669d96d074ad 100644
> --- a/include/linux/bpf-cgroup.h
> +++ b/include/linux/bpf-cgroup.h
> @@ -225,24 +225,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
>
>  #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype)                                      \
>  ({                                                                            \
> -       u32 __unused_flags;                                                    \
>         int __ret = 0;                                                         \
>         if (cgroup_bpf_enabled(atype))                                         \
>                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> -                                                         NULL,                \
> -                                                         &__unused_flags);    \
> +                                                         NULL, NULL);         \
>         __ret;                                                                 \
>  })
>
>  #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx)                  \
>  ({                                                                            \
> -       u32 __unused_flags;                                                    \
>         int __ret = 0;                                                         \
>         if (cgroup_bpf_enabled(atype))  {                                      \
>                 lock_sock(sk);                                                 \
>                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> -                                                         t_ctx,               \
> -                                                         &__unused_flags);    \
> +                                                         t_ctx, NULL);        \
>                 release_sock(sk);                                              \
>         }                                                                      \
>         __ret;                                                                 \
> diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
> index 0cb6211fcb58..f61eca32c747 100644
> --- a/kernel/bpf/cgroup.c
> +++ b/kernel/bpf/cgroup.c
> @@ -25,50 +25,18 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
>  /* __always_inline is necessary to prevent indirect call through run_prog
>   * function pointer.
>   */
> -static __always_inline int
> -bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
> -                           enum cgroup_bpf_attach_type atype,
> -                           const void *ctx, bpf_prog_run_fn run_prog,
> -                           int retval, u32 *ret_flags)
> -{
> -       const struct bpf_prog_array_item *item;
> -       const struct bpf_prog *prog;
> -       const struct bpf_prog_array *array;
> -       struct bpf_run_ctx *old_run_ctx;
> -       struct bpf_cg_run_ctx run_ctx;
> -       u32 func_ret;
> -
> -       run_ctx.retval = retval;
> -       migrate_disable();
> -       rcu_read_lock();
> -       array = rcu_dereference(cgrp->effective[atype]);
> -       item = &array->items[0];
> -       old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> -       while ((prog = READ_ONCE(item->prog))) {
> -               run_ctx.prog_item = item;
> -               func_ret = run_prog(prog, ctx);
> -               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
> -                       run_ctx.retval = -EPERM;
> -               *(ret_flags) |= (func_ret >> 1);
> -               item++;
> -       }
> -       bpf_reset_run_ctx(old_run_ctx);
> -       rcu_read_unlock();
> -       migrate_enable();
> -       return run_ctx.retval;
> -}
> -
>  static __always_inline int
>  bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
>                       enum cgroup_bpf_attach_type atype,
>                       const void *ctx, bpf_prog_run_fn run_prog,
> -                     int retval)
> +                     int retval, u32 *ret_flags)
>  {
>         const struct bpf_prog_array_item *item;
>         const struct bpf_prog *prog;
>         const struct bpf_prog_array *array;
>         struct bpf_run_ctx *old_run_ctx;
>         struct bpf_cg_run_ctx run_ctx;
> +       u32 func_ret;
>
>         run_ctx.retval = retval;
>         migrate_disable();
> @@ -78,8 +46,11 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
>         old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
>         while ((prog = READ_ONCE(item->prog))) {
>                 run_ctx.prog_item = item;
> -               if (!run_prog(prog, ctx) && !IS_ERR_VALUE((long)run_ctx.retval))
> +               func_ret = run_prog(prog, ctx);
> +               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))

to be completely true to previous behavior, shouldn't there be

if (ret_flags)
    func_ret &= 1;
if (!func_ret && !IS_ERR_VALUE(...))

here?

This might have been discussed previously and I missed it. If that's
so, please ignore.


>                         run_ctx.retval = -EPERM;
> +               if (ret_flags)
> +                       *(ret_flags) |= (func_ret >> 1);
>                 item++;
>         }
>         bpf_reset_run_ctx(old_run_ctx);

[..]

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere
  2022-04-20 22:04 ` Andrii Nakryiko
@ 2022-04-20 22:30   ` Stanislav Fomichev
  2022-04-25 20:37     ` Martin KaFai Lau
  0 siblings, 1 reply; 5+ messages in thread
From: Stanislav Fomichev @ 2022-04-20 22:30 UTC (permalink / raw)
  To: Andrii Nakryiko
  Cc: Networking, bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko

On Wed, Apr 20, 2022 at 3:04 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Tue, Apr 19, 2022 at 3:23 PM Stanislav Fomichev <sdf@google.com> wrote:
> >
> > Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
> > use it everywhere. check_return_code already enforces sane
> > return ranges for all cgroup types. (only egress and bind hooks have
> > uncanonical return ranges, the rest is using [0, 1])
> >
> > No functional changes.
> >
> > Suggested-by: Alexei Starovoitov <ast@kernel.org>
> > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > ---
> >  include/linux/bpf-cgroup.h |  8 ++---
> >  kernel/bpf/cgroup.c        | 70 ++++++++++++--------------------------
> >  2 files changed, 24 insertions(+), 54 deletions(-)
> >
> > diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
> > index 88a51b242adc..669d96d074ad 100644
> > --- a/include/linux/bpf-cgroup.h
> > +++ b/include/linux/bpf-cgroup.h
> > @@ -225,24 +225,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
> >
> >  #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype)                                      \
> >  ({                                                                            \
> > -       u32 __unused_flags;                                                    \
> >         int __ret = 0;                                                         \
> >         if (cgroup_bpf_enabled(atype))                                         \
> >                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> > -                                                         NULL,                \
> > -                                                         &__unused_flags);    \
> > +                                                         NULL, NULL);         \
> >         __ret;                                                                 \
> >  })
> >
> >  #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx)                  \
> >  ({                                                                            \
> > -       u32 __unused_flags;                                                    \
> >         int __ret = 0;                                                         \
> >         if (cgroup_bpf_enabled(atype))  {                                      \
> >                 lock_sock(sk);                                                 \
> >                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> > -                                                         t_ctx,               \
> > -                                                         &__unused_flags);    \
> > +                                                         t_ctx, NULL);        \
> >                 release_sock(sk);                                              \
> >         }                                                                      \
> >         __ret;                                                                 \
> > diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
> > index 0cb6211fcb58..f61eca32c747 100644
> > --- a/kernel/bpf/cgroup.c
> > +++ b/kernel/bpf/cgroup.c
> > @@ -25,50 +25,18 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
> >  /* __always_inline is necessary to prevent indirect call through run_prog
> >   * function pointer.
> >   */
> > -static __always_inline int
> > -bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
> > -                           enum cgroup_bpf_attach_type atype,
> > -                           const void *ctx, bpf_prog_run_fn run_prog,
> > -                           int retval, u32 *ret_flags)
> > -{
> > -       const struct bpf_prog_array_item *item;
> > -       const struct bpf_prog *prog;
> > -       const struct bpf_prog_array *array;
> > -       struct bpf_run_ctx *old_run_ctx;
> > -       struct bpf_cg_run_ctx run_ctx;
> > -       u32 func_ret;
> > -
> > -       run_ctx.retval = retval;
> > -       migrate_disable();
> > -       rcu_read_lock();
> > -       array = rcu_dereference(cgrp->effective[atype]);
> > -       item = &array->items[0];
> > -       old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> > -       while ((prog = READ_ONCE(item->prog))) {
> > -               run_ctx.prog_item = item;
> > -               func_ret = run_prog(prog, ctx);
> > -               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
> > -                       run_ctx.retval = -EPERM;
> > -               *(ret_flags) |= (func_ret >> 1);
> > -               item++;
> > -       }
> > -       bpf_reset_run_ctx(old_run_ctx);
> > -       rcu_read_unlock();
> > -       migrate_enable();
> > -       return run_ctx.retval;
> > -}
> > -
> >  static __always_inline int
> >  bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
> >                       enum cgroup_bpf_attach_type atype,
> >                       const void *ctx, bpf_prog_run_fn run_prog,
> > -                     int retval)
> > +                     int retval, u32 *ret_flags)
> >  {
> >         const struct bpf_prog_array_item *item;
> >         const struct bpf_prog *prog;
> >         const struct bpf_prog_array *array;
> >         struct bpf_run_ctx *old_run_ctx;
> >         struct bpf_cg_run_ctx run_ctx;
> > +       u32 func_ret;
> >
> >         run_ctx.retval = retval;
> >         migrate_disable();
> > @@ -78,8 +46,11 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
> >         old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> >         while ((prog = READ_ONCE(item->prog))) {
> >                 run_ctx.prog_item = item;
> > -               if (!run_prog(prog, ctx) && !IS_ERR_VALUE((long)run_ctx.retval))
> > +               func_ret = run_prog(prog, ctx);
> > +               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
>
> to be completely true to previous behavior, shouldn't there be
>
> if (ret_flags)
>     func_ret &= 1;
> if (!func_ret && !IS_ERR_VALUE(...))
>
> here?
>
> This might have been discussed previously and I missed it. If that's
> so, please ignore.

We are converting the cases where run_prog(prog, ctx) returns 0 or 1,
so it seems like we don't have to reproduce the existing behavior
1-to-1?
So I'm not sure it matters, or am I missing something?

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere
  2022-04-20 22:30   ` Stanislav Fomichev
@ 2022-04-25 20:37     ` Martin KaFai Lau
  2022-04-25 21:48       ` Stanislav Fomichev
  0 siblings, 1 reply; 5+ messages in thread
From: Martin KaFai Lau @ 2022-04-25 20:37 UTC (permalink / raw)
  To: Stanislav Fomichev
  Cc: Andrii Nakryiko, Networking, bpf, Alexei Starovoitov,
	Daniel Borkmann, Andrii Nakryiko

On Wed, Apr 20, 2022 at 03:30:43PM -0700, Stanislav Fomichev wrote:
> On Wed, Apr 20, 2022 at 3:04 PM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > On Tue, Apr 19, 2022 at 3:23 PM Stanislav Fomichev <sdf@google.com> wrote:
> > >
> > > Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
> > > use it everywhere. check_return_code already enforces sane
> > > return ranges for all cgroup types. (only egress and bind hooks have
> > > uncanonical return ranges, the rest is using [0, 1])
> > >
> > > No functional changes.
> > >
> > > Suggested-by: Alexei Starovoitov <ast@kernel.org>
> > > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > > ---
> > >  include/linux/bpf-cgroup.h |  8 ++---
> > >  kernel/bpf/cgroup.c        | 70 ++++++++++++--------------------------
> > >  2 files changed, 24 insertions(+), 54 deletions(-)
> > >
> > > diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
> > > index 88a51b242adc..669d96d074ad 100644
> > > --- a/include/linux/bpf-cgroup.h
> > > +++ b/include/linux/bpf-cgroup.h
> > > @@ -225,24 +225,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
> > >
> > >  #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype)                                      \
> > >  ({                                                                            \
> > > -       u32 __unused_flags;                                                    \
> > >         int __ret = 0;                                                         \
> > >         if (cgroup_bpf_enabled(atype))                                         \
> > >                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> > > -                                                         NULL,                \
> > > -                                                         &__unused_flags);    \
> > > +                                                         NULL, NULL);         \
> > >         __ret;                                                                 \
> > >  })
> > >
> > >  #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx)                  \
> > >  ({                                                                            \
> > > -       u32 __unused_flags;                                                    \
> > >         int __ret = 0;                                                         \
> > >         if (cgroup_bpf_enabled(atype))  {                                      \
> > >                 lock_sock(sk);                                                 \
> > >                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> > > -                                                         t_ctx,               \
> > > -                                                         &__unused_flags);    \
> > > +                                                         t_ctx, NULL);        \
> > >                 release_sock(sk);                                              \
> > >         }                                                                      \
> > >         __ret;                                                                 \
> > > diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
> > > index 0cb6211fcb58..f61eca32c747 100644
> > > --- a/kernel/bpf/cgroup.c
> > > +++ b/kernel/bpf/cgroup.c
> > > @@ -25,50 +25,18 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
> > >  /* __always_inline is necessary to prevent indirect call through run_prog
> > >   * function pointer.
> > >   */
> > > -static __always_inline int
> > > -bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
> > > -                           enum cgroup_bpf_attach_type atype,
> > > -                           const void *ctx, bpf_prog_run_fn run_prog,
> > > -                           int retval, u32 *ret_flags)
> > > -{
> > > -       const struct bpf_prog_array_item *item;
> > > -       const struct bpf_prog *prog;
> > > -       const struct bpf_prog_array *array;
> > > -       struct bpf_run_ctx *old_run_ctx;
> > > -       struct bpf_cg_run_ctx run_ctx;
> > > -       u32 func_ret;
> > > -
> > > -       run_ctx.retval = retval;
> > > -       migrate_disable();
> > > -       rcu_read_lock();
> > > -       array = rcu_dereference(cgrp->effective[atype]);
> > > -       item = &array->items[0];
> > > -       old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> > > -       while ((prog = READ_ONCE(item->prog))) {
> > > -               run_ctx.prog_item = item;
> > > -               func_ret = run_prog(prog, ctx);
> > > -               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
> > > -                       run_ctx.retval = -EPERM;
> > > -               *(ret_flags) |= (func_ret >> 1);
> > > -               item++;
> > > -       }
> > > -       bpf_reset_run_ctx(old_run_ctx);
> > > -       rcu_read_unlock();
> > > -       migrate_enable();
> > > -       return run_ctx.retval;
> > > -}
> > > -
> > >  static __always_inline int
> > >  bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
> > >                       enum cgroup_bpf_attach_type atype,
> > >                       const void *ctx, bpf_prog_run_fn run_prog,
> > > -                     int retval)
> > > +                     int retval, u32 *ret_flags)
> > >  {
> > >         const struct bpf_prog_array_item *item;
> > >         const struct bpf_prog *prog;
> > >         const struct bpf_prog_array *array;
> > >         struct bpf_run_ctx *old_run_ctx;
> > >         struct bpf_cg_run_ctx run_ctx;
> > > +       u32 func_ret;
> > >
> > >         run_ctx.retval = retval;
> > >         migrate_disable();
> > > @@ -78,8 +46,11 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
> > >         old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> > >         while ((prog = READ_ONCE(item->prog))) {
> > >                 run_ctx.prog_item = item;
> > > -               if (!run_prog(prog, ctx) && !IS_ERR_VALUE((long)run_ctx.retval))
> > > +               func_ret = run_prog(prog, ctx);
> > > +               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
> >
> > to be completely true to previous behavior, shouldn't there be
> >
> > if (ret_flags)
> >     func_ret &= 1;
> > if (!func_ret && !IS_ERR_VALUE(...))
> >
> > here?
> >
> > This might have been discussed previously and I missed it. If that's
> > so, please ignore.
> 
> We are converting the cases where run_prog(prog, ctx) returns 0 or 1,
> so it seems like we don't have to reproduce the existing behavior
> 1-to-1?
> So I'm not sure it matters, or am I missing something?
A nit, how about testing 'if (ret_flags)' first such that
it is obvious which case will use higher bits in the return value.
The compiler may be able to optimize the ret_flags == NULL case also ?

Something like:

	func_ret = run_prog(prog, ctx);
	/* The cg bpf prog uses the higher bits of the return value */
	if (ret_flags) {
		*(ret_flags) |= (func_ret >> 1);
		func_ret &= 1;
	}
	if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval))
		run_ctx.retval = -EPERM;

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere
  2022-04-25 20:37     ` Martin KaFai Lau
@ 2022-04-25 21:48       ` Stanislav Fomichev
  0 siblings, 0 replies; 5+ messages in thread
From: Stanislav Fomichev @ 2022-04-25 21:48 UTC (permalink / raw)
  To: Martin KaFai Lau
  Cc: Andrii Nakryiko, Networking, bpf, Alexei Starovoitov,
	Daniel Borkmann, Andrii Nakryiko

On Mon, Apr 25, 2022 at 1:38 PM Martin KaFai Lau <kafai@fb.com> wrote:
>
> On Wed, Apr 20, 2022 at 03:30:43PM -0700, Stanislav Fomichev wrote:
> > On Wed, Apr 20, 2022 at 3:04 PM Andrii Nakryiko
> > <andrii.nakryiko@gmail.com> wrote:
> > >
> > > On Tue, Apr 19, 2022 at 3:23 PM Stanislav Fomichev <sdf@google.com> wrote:
> > > >
> > > > Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
> > > > use it everywhere. check_return_code already enforces sane
> > > > return ranges for all cgroup types. (only egress and bind hooks have
> > > > uncanonical return ranges, the rest is using [0, 1])
> > > >
> > > > No functional changes.
> > > >
> > > > Suggested-by: Alexei Starovoitov <ast@kernel.org>
> > > > Signed-off-by: Stanislav Fomichev <sdf@google.com>
> > > > ---
> > > >  include/linux/bpf-cgroup.h |  8 ++---
> > > >  kernel/bpf/cgroup.c        | 70 ++++++++++++--------------------------
> > > >  2 files changed, 24 insertions(+), 54 deletions(-)
> > > >
> > > > diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
> > > > index 88a51b242adc..669d96d074ad 100644
> > > > --- a/include/linux/bpf-cgroup.h
> > > > +++ b/include/linux/bpf-cgroup.h
> > > > @@ -225,24 +225,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,
> > > >
> > > >  #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype)                                      \
> > > >  ({                                                                            \
> > > > -       u32 __unused_flags;                                                    \
> > > >         int __ret = 0;                                                         \
> > > >         if (cgroup_bpf_enabled(atype))                                         \
> > > >                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> > > > -                                                         NULL,                \
> > > > -                                                         &__unused_flags);    \
> > > > +                                                         NULL, NULL);         \
> > > >         __ret;                                                                 \
> > > >  })
> > > >
> > > >  #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx)                  \
> > > >  ({                                                                            \
> > > > -       u32 __unused_flags;                                                    \
> > > >         int __ret = 0;                                                         \
> > > >         if (cgroup_bpf_enabled(atype))  {                                      \
> > > >                 lock_sock(sk);                                                 \
> > > >                 __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype,     \
> > > > -                                                         t_ctx,               \
> > > > -                                                         &__unused_flags);    \
> > > > +                                                         t_ctx, NULL);        \
> > > >                 release_sock(sk);                                              \
> > > >         }                                                                      \
> > > >         __ret;                                                                 \
> > > > diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
> > > > index 0cb6211fcb58..f61eca32c747 100644
> > > > --- a/kernel/bpf/cgroup.c
> > > > +++ b/kernel/bpf/cgroup.c
> > > > @@ -25,50 +25,18 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
> > > >  /* __always_inline is necessary to prevent indirect call through run_prog
> > > >   * function pointer.
> > > >   */
> > > > -static __always_inline int
> > > > -bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
> > > > -                           enum cgroup_bpf_attach_type atype,
> > > > -                           const void *ctx, bpf_prog_run_fn run_prog,
> > > > -                           int retval, u32 *ret_flags)
> > > > -{
> > > > -       const struct bpf_prog_array_item *item;
> > > > -       const struct bpf_prog *prog;
> > > > -       const struct bpf_prog_array *array;
> > > > -       struct bpf_run_ctx *old_run_ctx;
> > > > -       struct bpf_cg_run_ctx run_ctx;
> > > > -       u32 func_ret;
> > > > -
> > > > -       run_ctx.retval = retval;
> > > > -       migrate_disable();
> > > > -       rcu_read_lock();
> > > > -       array = rcu_dereference(cgrp->effective[atype]);
> > > > -       item = &array->items[0];
> > > > -       old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> > > > -       while ((prog = READ_ONCE(item->prog))) {
> > > > -               run_ctx.prog_item = item;
> > > > -               func_ret = run_prog(prog, ctx);
> > > > -               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
> > > > -                       run_ctx.retval = -EPERM;
> > > > -               *(ret_flags) |= (func_ret >> 1);
> > > > -               item++;
> > > > -       }
> > > > -       bpf_reset_run_ctx(old_run_ctx);
> > > > -       rcu_read_unlock();
> > > > -       migrate_enable();
> > > > -       return run_ctx.retval;
> > > > -}
> > > > -
> > > >  static __always_inline int
> > > >  bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
> > > >                       enum cgroup_bpf_attach_type atype,
> > > >                       const void *ctx, bpf_prog_run_fn run_prog,
> > > > -                     int retval)
> > > > +                     int retval, u32 *ret_flags)
> > > >  {
> > > >         const struct bpf_prog_array_item *item;
> > > >         const struct bpf_prog *prog;
> > > >         const struct bpf_prog_array *array;
> > > >         struct bpf_run_ctx *old_run_ctx;
> > > >         struct bpf_cg_run_ctx run_ctx;
> > > > +       u32 func_ret;
> > > >
> > > >         run_ctx.retval = retval;
> > > >         migrate_disable();
> > > > @@ -78,8 +46,11 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
> > > >         old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> > > >         while ((prog = READ_ONCE(item->prog))) {
> > > >                 run_ctx.prog_item = item;
> > > > -               if (!run_prog(prog, ctx) && !IS_ERR_VALUE((long)run_ctx.retval))
> > > > +               func_ret = run_prog(prog, ctx);
> > > > +               if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
> > >
> > > to be completely true to previous behavior, shouldn't there be
> > >
> > > if (ret_flags)
> > >     func_ret &= 1;
> > > if (!func_ret && !IS_ERR_VALUE(...))
> > >
> > > here?
> > >
> > > This might have been discussed previously and I missed it. If that's
> > > so, please ignore.
> >
> > We are converting the cases where run_prog(prog, ctx) returns 0 or 1,
> > so it seems like we don't have to reproduce the existing behavior
> > 1-to-1?
> > So I'm not sure it matters, or am I missing something?
> A nit, how about testing 'if (ret_flags)' first such that
> it is obvious which case will use higher bits in the return value.
> The compiler may be able to optimize the ret_flags == NULL case also ?
>
> Something like:
>
>         func_ret = run_prog(prog, ctx);
>         /* The cg bpf prog uses the higher bits of the return value */
>         if (ret_flags) {
>                 *(ret_flags) |= (func_ret >> 1);
>                 func_ret &= 1;
>         }
>         if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval))
>                 run_ctx.retval = -EPERM;

Sure, this should also address Andrii's point I think. Will resend a v2.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2022-04-25 22:21 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-19 22:22 [PATCH bpf-next] bpf: use bpf_prog_run_array_cg_flags everywhere Stanislav Fomichev
2022-04-20 22:04 ` Andrii Nakryiko
2022-04-20 22:30   ` Stanislav Fomichev
2022-04-25 20:37     ` Martin KaFai Lau
2022-04-25 21:48       ` Stanislav Fomichev

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