net/sched: forbid 'goto_chain' on fallback actions

PATCH In review Davide Caratti 5 participants 11 messages Oct 21, 2018 – Oct 23, 2018

Subsystems (4)

Networking Network drivers Kselftest Traffic control (tc)

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Davide Caratti

author

2018-10-21 05:45 UTC #0 lore raw

cover net/sched: forbid 'goto_chain' on fallback actions

the following command:

 # tc actions add action police rate 1mbit burst 1k conform-exceed \

Quoted 1 line

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(-)

Signature · 1 line

2.17.1

Davide Caratti

author

2018-10-21 05:45 UTC #1 lore raw

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

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 <[email protected]>

---
 net/sched/act_gact.c | 5 +++++
 1 file changed, 5 insertions(+)

net/sched/act_gact.c +5 -0

index cd1d9bd32ef9..505138047e5c 100644
@@ -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

Signature · 1 line

2.17.1

Cong Wang

Acked-by on v1 1/4

2018-10-23 00:41 UTC #2 lore raw

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

Quoted 10 lines · 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 <[email protected]>

Acked-by Cong Wang <[email protected]>

Jiri Pirko

maintainer Acked-by on v1 1/4

2018-10-23 05:21 UTC #3 lore raw

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

In reply to Davide Caratti

Quoted 18 lines · Sat, Oct 20, 2018 at 11:33:07PM CEST, [email protected] 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 <[email protected]>
---
net/sched/act_gact.c | 5 +++++
1 file changed, 5 insertions(+)
net/sched/act_gact.c +0 -0
index cd1d9bd32ef9..505138047e5c 100644

net/sched/act_gact.c static int tcf_gact_init(struct net *net, struct nlattr *nla, · line 93

Quoted 6 lines

net/sched/act_gact.c +3 -0

@@ -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 <[email protected]>

Davide Caratti

author

2018-10-21 05:45 UTC #4 lore raw

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

In reply to 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 <[email protected]>

---
 net/sched/act_police.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

net/sched/act_police.c +10 -2

index 5d8bfa878477..3b793393efd1 100644
@@ -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) {

Signature · 1 line

2.17.1

Cong Wang

Acked-by on v1 2/4

2018-10-23 00:42 UTC #5 lore raw

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

Quoted 10 lines · 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 <[email protected]>

Acked-by Cong Wang <[email protected]>

Jiri Pirko

maintainer Acked-by on v1 2/4

2018-10-23 05:23 UTC #6 lore raw

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

In reply to Davide Caratti

Quoted 18 lines · Sat, Oct 20, 2018 at 11:33:08PM CEST, [email protected] 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 <[email protected]>
---
net/sched/act_police.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
net/sched/act_police.c +0 -0
index 5d8bfa878477..3b793393efd1 100644

net/sched/act_police.c static int tcf_police_init(struct net *net, struct nlattr *nla, · line 157

Quoted 8 lines

net/sched/act_police.c +5 -0

@@ -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 <[email protected]>

Quoted 20 lines

net/sched/act_police.c +5 -2

+			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) {

Signature · 1 line

2.17.1

Davide Caratti

author

2018-10-21 05:45 UTC #7 lore raw

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

In reply to 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 <[email protected]>

---
 .../tc-testing/tc-tests/actions/gact.json     | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

tools/testing/selftests/tc-testing/tc-tests/actions/gact.json +24 -0

index 68c91023cdb9..89189a03ce3d 100644
@@ -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"
+        ]
     }
 ]

Signature · 1 line

2.17.1

Davide Caratti

author

2018-10-21 05:45 UTC #8 lore raw

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

In reply to Davide Caratti

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

Signed-off-by Davide Caratti <[email protected]>

---
 .../tc-testing/tc-tests/actions/police.json   | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

tools/testing/selftests/tc-testing/tc-tests/actions/police.json +24 -0

index 30f9b54bd666..4086a50a670e 100644
@@ -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"
+        ]
     }
 ]

Signature · 1 line

2.17.1

Jamal Hadi Salim

maintainer Acked-by on the v1 series

2018-10-23 02:59 UTC #9 lore raw

In reply to Davide Caratti

Quoted 20 lines · Davide Caratti

the following command:
  # tc actions add action police rate 1mbit burst 1k conform-exceed \
Quoted 1 line
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.

Quoted 4 lines

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 <[email protected]>

cheers,
jamal

David Miller

maintainer

2018-10-23 11:04 UTC #10 lore raw

In reply to Davide Caratti

From: Davide Caratti <[email protected]>
Date: Sat, 20 Oct 2018 23:33:06 +0200

Quoted 20 lines

the following command:
 # tc actions add action police rate 1mbit burst 1k conform-exceed \
Quoted 1 line
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.

Quoted 3 lines

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.