[PATCH net 0/4] net/sched: forbid 'goto_chain' on fallback actions

[PATCH net 0/4] net/sched: forbid 'goto_chain' on fallback actions

[Davide Caratti]

the following command:

 # tc actions add action police rate 1mbit burst 1k conform-exceed \
 > pass / goto chain 42

generates a NULL pointer dereference when packets exceed the configured
rate. Similarly, the following command:

 # tc actions add action pass random determ goto chain 42 2

makes the kernel crash with NULL dereference when the first packet does
not match the 'pass' action.

gact and police allow users to specify a fallback control action, that is
stored in the action private data. 'goto chain x' never worked for these
cases, since a->goto_chain handle was never initialized. There is only one
goto_chain handle per TC action, and it is designed to be non-NULL only if
tcf_action contains a 'goto chain' command. So, let's forbid 'goto chain'
on fallback actions.

Patch 1/4 and 2/4 change the .init() functions of police and gact, to let
them return an error when users try to set 'goto chain x' in the fallback
action. Patch 3/4 and 4/4 add TDC selftest coverage to this new behavior. 

Davide Caratti (4):
  net/sched: act_gact: disallow 'goto chain' on fallback control action
  net/sched: act_police: disallow 'goto chain' on fallback control
    action
  tc-tests: test denial of 'goto chain' on 'random' traffic in gact.json
  tc-tests: test denial of 'goto chain' for exceed traffic in
    police.json

 net/sched/act_gact.c                          |  5 ++++
 net/sched/act_police.c                        | 12 ++++++++--
 .../tc-testing/tc-tests/actions/gact.json     | 24 +++++++++++++++++++
 .../tc-testing/tc-tests/actions/police.json   | 24 +++++++++++++++++++
 4 files changed, 63 insertions(+), 2 deletions(-)

-- 
2.17.1

[PATCH net 1/4] net/sched: act_gact: disallow 'goto chain' on fallback control action

[Davide Caratti]

in the following command:

 # tc action add action <c1> random <rand_type> <c2> <rand_param>

'goto chain x' is allowed only for c1: setting it for c2 makes the kernel
crash with NULL pointer dereference, since TC core doesn't initialize the
chain handle.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 net/sched/act_gact.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index cd1d9bd32ef9..505138047e5c 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -88,6 +88,11 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 		p_parm = nla_data(tb[TCA_GACT_PROB]);
 		if (p_parm->ptype >= MAX_RAND)
 			return -EINVAL;
+		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
+			NL_SET_ERR_MSG(extack,
+				       "goto chain not allowed on fallback");
+			return -EINVAL;
+		}
 	}
 #endif
 
-- 
2.17.1

Re: [PATCH net 1/4] net/sched: act_gact: disallow 'goto chain' on fallback control action

[Cong Wang]

On Sat, Oct 20, 2018 at 2:33 PM Davide Caratti <dcaratti@redhat.com> wrote:
>
> in the following command:
>
>  # tc action add action <c1> random <rand_type> <c2> <rand_param>
>
> 'goto chain x' is allowed only for c1: setting it for c2 makes the kernel
> crash with NULL pointer dereference, since TC core doesn't initialize the
> chain handle.
>
> Signed-off-by: Davide Caratti <dcaratti@redhat.com>

Acked-by: Cong Wang <xiyou.wangcong@gmail.com>

Re: [PATCH net 1/4] net/sched: act_gact: disallow 'goto chain' on fallback control action

[Jiri Pirko]

Sat, Oct 20, 2018 at 11:33:07PM CEST, dcaratti@redhat.com wrote:
>in the following command:
>
> # tc action add action <c1> random <rand_type> <c2> <rand_param>
>
>'goto chain x' is allowed only for c1: setting it for c2 makes the kernel
>crash with NULL pointer dereference, since TC core doesn't initialize the
>chain handle.
>
>Signed-off-by: Davide Caratti <dcaratti@redhat.com>
>---
> net/sched/act_gact.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
>diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
>index cd1d9bd32ef9..505138047e5c 100644
>--- a/net/sched/act_gact.c
>+++ b/net/sched/act_gact.c
>@@ -88,6 +88,11 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
> 		p_parm = nla_data(tb[TCA_GACT_PROB]);
> 		if (p_parm->ptype >= MAX_RAND)
> 			return -EINVAL;
>+		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
>+			NL_SET_ERR_MSG(extack,
>+				       "goto chain not allowed on fallback");

No need for a line-wrap. Otherwise
Acked-by: Jiri Pirko <jiri@mellanox.com>

[PATCH net 2/4] net/sched: act_police: disallow 'goto chain' on fallback control action

[Davide Caratti]

in the following command:

 # tc action add action police rate <r> burst <b> conform-exceed <c1>/<c2>

'goto chain x' is allowed only for c1: setting it for c2 makes the kernel
crash with NULL pointer dereference, since TC core doesn't initialize the
chain handle.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 net/sched/act_police.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 5d8bfa878477..3b793393efd1 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -150,6 +150,16 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
 		goto failure;
 	}
 
+	if (tb[TCA_POLICE_RESULT]) {
+		police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
+		if (TC_ACT_EXT_CMP(police->tcfp_result, TC_ACT_GOTO_CHAIN)) {
+			NL_SET_ERR_MSG(extack,
+				       "goto chain not allowed on fallback");
+			err = -EINVAL;
+			goto failure;
+		}
+	}
+
 	spin_lock_bh(&police->tcf_lock);
 	/* No failure allowed after this point */
 	police->tcfp_mtu = parm->mtu;
@@ -173,8 +183,6 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
 		police->peak_present = false;
 	}
 
-	if (tb[TCA_POLICE_RESULT])
-		police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 	police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
 	police->tcfp_toks = police->tcfp_burst;
 	if (police->peak_present) {
-- 
2.17.1

Re: [PATCH net 2/4] net/sched: act_police: disallow 'goto chain' on fallback control action

[Cong Wang]

On Sat, Oct 20, 2018 at 2:33 PM Davide Caratti <dcaratti@redhat.com> wrote:
>
> in the following command:
>
>  # tc action add action police rate <r> burst <b> conform-exceed <c1>/<c2>
>
> 'goto chain x' is allowed only for c1: setting it for c2 makes the kernel
> crash with NULL pointer dereference, since TC core doesn't initialize the
> chain handle.
>
> Signed-off-by: Davide Caratti <dcaratti@redhat.com>

Acked-by: Cong Wang <xiyou.wangcong@gmail.com>

Re: [PATCH net 2/4] net/sched: act_police: disallow 'goto chain' on fallback control action

[Jiri Pirko]

Sat, Oct 20, 2018 at 11:33:08PM CEST, dcaratti@redhat.com wrote:
>in the following command:
>
> # tc action add action police rate <r> burst <b> conform-exceed <c1>/<c2>
>
>'goto chain x' is allowed only for c1: setting it for c2 makes the kernel
>crash with NULL pointer dereference, since TC core doesn't initialize the
>chain handle.
>
>Signed-off-by: Davide Caratti <dcaratti@redhat.com>
>---
> net/sched/act_police.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
>diff --git a/net/sched/act_police.c b/net/sched/act_police.c
>index 5d8bfa878477..3b793393efd1 100644
>--- a/net/sched/act_police.c
>+++ b/net/sched/act_police.c
>@@ -150,6 +150,16 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
> 		goto failure;
> 	}
> 
>+	if (tb[TCA_POLICE_RESULT]) {
>+		police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
>+		if (TC_ACT_EXT_CMP(police->tcfp_result, TC_ACT_GOTO_CHAIN)) {
>+			NL_SET_ERR_MSG(extack,
>+				       "goto chain not allowed on fallback");

Also, no need for line-wrap

Acked-by: Jiri Pirko <jiri@mellanox.com>



>+			err = -EINVAL;
>+			goto failure;
>+		}
>+	}
>+
> 	spin_lock_bh(&police->tcf_lock);
> 	/* No failure allowed after this point */
> 	police->tcfp_mtu = parm->mtu;
>@@ -173,8 +183,6 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
> 		police->peak_present = false;
> 	}
> 
>-	if (tb[TCA_POLICE_RESULT])
>-		police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
> 	police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
> 	police->tcfp_toks = police->tcfp_burst;
> 	if (police->peak_present) {
>-- 
>2.17.1
>

[PATCH net 3/4] tc-tests: test denial of 'goto chain' on 'random' traffic in gact.json

[Davide Caratti]

add test to verify if act_gact forbids 'goto chain' control actions on
'random' traffic in gact.json.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 .../tc-testing/tc-tests/actions/gact.json     | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/gact.json b/tools/testing/selftests/tc-testing/tc-tests/actions/gact.json
index 68c91023cdb9..89189a03ce3d 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/actions/gact.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/gact.json
@@ -536,5 +536,29 @@
         "matchPattern": "^[ \t]+index [0-9]+ ref",
         "matchCount": "0",
         "teardown": []
+    },
+    {
+        "id": "8e47",
+        "name": "Add gact action with random determ goto chain control action",
+        "category": [
+            "actions",
+            "gact"
+        ],
+        "setup": [
+            [
+                "$TC actions flush action gact",
+                0,
+                1,
+                255
+            ]
+        ],
+        "cmdUnderTest": "$TC actions add action pass random determ goto chain 1 2 index 90",
+        "expExitCode": "255",
+        "verifyCmd": "$TC actions list action gact",
+        "matchPattern": "action order [0-9]*: gact action pass random type determ goto chain 1 val 2.*index 90 ref",
+        "matchCount": "0",
+        "teardown": [
+            "$TC actions flush action gact"
+        ]
     }
 ]
-- 
2.17.1

[PATCH net 4/4] tc-tests: test denial of 'goto chain' for exceed traffic in police.json

[Davide Caratti]

add test to verify if act_police forbids 'goto chain' control actions for
'exceed' traffic.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 .../tc-testing/tc-tests/actions/police.json   | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/police.json b/tools/testing/selftests/tc-testing/tc-tests/actions/police.json
index 30f9b54bd666..4086a50a670e 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/actions/police.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/police.json
@@ -715,5 +715,29 @@
         "teardown": [
             "$TC actions flush action police"
         ]
+    },
+    {
+        "id": "b48b",
+        "name": "Add police action with exceed goto chain control action",
+        "category": [
+            "actions",
+            "police"
+        ],
+        "setup": [
+            [
+                "$TC actions flush action police",
+                0,
+                1,
+                255
+            ]
+        ],
+        "cmdUnderTest": "$TC actions add action police rate 1mbit burst 1k conform-exceed pass / goto chain 42",
+        "expExitCode": "255",
+        "verifyCmd": "$TC actions ls action police",
+        "matchPattern": "action order [0-9]*:  police 0x1 rate 1Mbit burst 1Kb mtu 2Kb action pass/goto chain 42",
+        "matchCount": "0",
+        "teardown": [
+            "$TC actions flush action police"
+        ]
     }
 ]
-- 
2.17.1

Re: [PATCH net 0/4] net/sched: forbid 'goto_chain' on fallback actions

[Jamal Hadi Salim]

On 2018-10-20 5:33 p.m., Davide Caratti wrote:
> the following command:
> 
>   # tc actions add action police rate 1mbit burst 1k conform-exceed \
>   > pass / goto chain 42
> 
> generates a NULL pointer dereference when packets exceed the configured
> rate. Similarly, the following command:
> 
>   # tc actions add action pass random determ goto chain 42 2
> 
> makes the kernel crash with NULL dereference when the first packet does
> not match the 'pass' action.
> 
> gact and police allow users to specify a fallback control action, that is
> stored in the action private data. 'goto chain x' never worked for these
> cases, since a->goto_chain handle was never initialized. There is only one
> goto_chain handle per TC action, and it is designed to be non-NULL only if
> tcf_action contains a 'goto chain' command. So, let's forbid 'goto chain'
> on fallback actions.
> 
> Patch 1/4 and 2/4 change the .init() functions of police and gact, to let
> them return an error when users try to set 'goto chain x' in the fallback
> action. Patch 3/4 and 4/4 add TDC selftest coverage to this new behavior.
> 

For the series,
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>

cheers,
jamal

Re: [PATCH net 0/4] net/sched: forbid 'goto_chain' on fallback actions

[David Miller]

From: Davide Caratti <dcaratti@redhat.com>
Date: Sat, 20 Oct 2018 23:33:06 +0200

> the following command:
> 
>  # tc actions add action police rate 1mbit burst 1k conform-exceed \
>  > pass / goto chain 42
> 
> generates a NULL pointer dereference when packets exceed the configured
> rate. Similarly, the following command:
> 
>  # tc actions add action pass random determ goto chain 42 2
> 
> makes the kernel crash with NULL dereference when the first packet does
> not match the 'pass' action.
> 
> gact and police allow users to specify a fallback control action, that is
> stored in the action private data. 'goto chain x' never worked for these
> cases, since a->goto_chain handle was never initialized. There is only one
> goto_chain handle per TC action, and it is designed to be non-NULL only if
> tcf_action contains a 'goto chain' command. So, let's forbid 'goto chain'
> on fallback actions.
> 
> Patch 1/4 and 2/4 change the .init() functions of police and gact, to let
> them return an error when users try to set 'goto chain x' in the fallback
> action. Patch 3/4 and 4/4 add TDC selftest coverage to this new behavior. 

Series applied.