diff mbox series

[net,v3,4/4] ip6mr: Lock RCU before ip6mr_get_table() call in ip6mr_get_route()

Message ID 20241010090741.1980100-9-stefan.wiehler@nokia.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series [net,v3,1/4] ip6mr: Lock RCU before ip6mr_get_table() call in ip6mr_vif_seq_start() | expand

Checks

Context Check Description
netdev/series_format warning Series does not have a cover letter
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 6 this patch: 6
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 6 maintainers
netdev/build_clang success Errors and warnings before: 9 this patch: 9
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 Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 7 this patch: 7
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 50 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

Stefan Wiehler Oct. 10, 2024, 9:07 a.m. UTC 
When IPV6_MROUTE_MULTIPLE_TABLES is enabled, calls to ip6mr_get_table()
must be done under RCU or RTNL lock.

Signed-off-by: Stefan Wiehler <stefan.wiehler@nokia.com>
Fixes: d1db275dd3f6 ("ipv6: ip6mr: support multiple tables")
---
v3:
  - split into separate patches
v2: https://patchwork.kernel.org/project/netdevbpf/patch/20241001100119.230711-2-stefan.wiehler@nokia.com/
  - rebase on top of net tree
  - add Fixes tag
  - refactor out paths
v1: https://patchwork.kernel.org/project/netdevbpf/patch/20240605195355.363936-1-oss@malat.biz/
---
 net/ipv6/ip6mr.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

Comments

Eric Dumazet Oct. 10, 2024, 9:33 a.m. UTC | #1 
On Thu, Oct 10, 2024 at 11:12 AM Stefan Wiehler
<stefan.wiehler@nokia.com> wrote:
>
> When IPV6_MROUTE_MULTIPLE_TABLES is enabled, calls to ip6mr_get_table()
> must be done under RCU or RTNL lock.
>
> Signed-off-by: Stefan Wiehler <stefan.wiehler@nokia.com>
> Fixes: d1db275dd3f6 ("ipv6: ip6mr: support multiple tables")
> ---

Please send a cover letter in your next version.

Please add a 5th patch in the series reverting

commit b6dd5acde3f165e364881c36de942c5b252e2a27
Author: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Date:   Sat May 16 13:15:15 2020 +0530

    ipv6: Fix suspicious RCU usage warning in ip6mr

This way, tests will detect more easily if something is wrong.

Thank you.
diff mbox series

Patch

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 415ba6f55a44..0bc8d6b0569f 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2302,11 +2302,13 @@  int ip6mr_get_route(struct net *net, struct sk_buff *skb, struct rtmsg *rtm,
 	struct mfc6_cache *cache;
 	struct rt6_info *rt = dst_rt6_info(skb_dst(skb));
 
+	rcu_read_lock();
 	mrt = ip6mr_get_table(net, RT6_TABLE_DFLT);
-	if (!mrt)
-		return -ENOENT;
+	if (!mrt) {
+		err = -ENOENT;
+		goto out;
+	}
 
-	rcu_read_lock();
 	cache = ip6mr_cache_find(mrt, &rt->rt6i_src.addr, &rt->rt6i_dst.addr);
 	if (!cache && skb->dev) {
 		int vif = ip6mr_find_vif(mrt, skb->dev);
@@ -2324,15 +2326,15 @@  int ip6mr_get_route(struct net *net, struct sk_buff *skb, struct rtmsg *rtm,
 
 		dev = skb->dev;
 		if (!dev || (vif = ip6mr_find_vif(mrt, dev)) < 0) {
-			rcu_read_unlock();
-			return -ENODEV;
+			err = -ENODEV;
+			goto out;
 		}
 
 		/* really correct? */
 		skb2 = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
 		if (!skb2) {
-			rcu_read_unlock();
-			return -ENOMEM;
+			err = -ENOMEM;
+			goto out;
 		}
 
 		NETLINK_CB(skb2).portid = portid;
@@ -2354,12 +2356,13 @@  int ip6mr_get_route(struct net *net, struct sk_buff *skb, struct rtmsg *rtm,
 		iph->daddr = rt->rt6i_dst.addr;
 
 		err = ip6mr_cache_unresolved(mrt, vif, skb2, dev);
-		rcu_read_unlock();
 
-		return err;
+		goto out;
 	}
 
 	err = mr_fill_mroute(mrt, skb, &cache->_c, rtm);
+
+out:
 	rcu_read_unlock();
 	return err;
 }