diff mbox series

[net,3/4] net: mctp: hold key reference when looking up a general key

Message ID 20230124020106.743966-4-jk@codeconstruct.com.au (mailing list archive)
State Accepted
Commit 6e54ea37e344f145665c2dc3cc534b92529e8de5
Delegated to: Netdev Maintainers
Headers show
Series net: mctp: struct sock lifetime fixes | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 4 this patch: 4
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 1 this patch: 1
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
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: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 34 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jeremy Kerr Jan. 24, 2023, 2:01 a.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

Currently, we have a race where we look up a sock through a "general"
(ie, not directly associated with the (src,dest,tag) tuple) key, then
drop the key reference while still holding the key's sock.

This change expands the key reference until we've finished using the
sock, and hence the sock reference too.

Commit message changes from Jeremy Kerr <jk@codeconstruct.com.au>.

Reported-by: Noam Rathaus <noamr@ssd-disclosure.com>
Fixes: 73c618456dc5 ("mctp: locking, lifetime and validity changes for sk_keys")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 net/mctp/route.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/net/mctp/route.c b/net/mctp/route.c
index ce10ba7ae839..06c0de21984d 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -317,8 +317,8 @@  static int mctp_frag_queue(struct mctp_sk_key *key, struct sk_buff *skb)
 
 static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
 {
+	struct mctp_sk_key *key, *any_key = NULL;
 	struct net *net = dev_net(skb->dev);
-	struct mctp_sk_key *key;
 	struct mctp_sock *msk;
 	struct mctp_hdr *mh;
 	unsigned long f;
@@ -363,13 +363,11 @@  static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
 			 * key for reassembly - we'll create a more specific
 			 * one for future packets if required (ie, !EOM).
 			 */
-			key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f);
-			if (key) {
-				msk = container_of(key->sk,
+			any_key = mctp_lookup_key(net, skb, MCTP_ADDR_ANY, &f);
+			if (any_key) {
+				msk = container_of(any_key->sk,
 						   struct mctp_sock, sk);
-				spin_unlock_irqrestore(&key->lock, f);
-				mctp_key_unref(key);
-				key = NULL;
+				spin_unlock_irqrestore(&any_key->lock, f);
 			}
 		}
 
@@ -475,6 +473,8 @@  static int mctp_route_input(struct mctp_route *route, struct sk_buff *skb)
 		spin_unlock_irqrestore(&key->lock, f);
 		mctp_key_unref(key);
 	}
+	if (any_key)
+		mctp_key_unref(any_key);
 out:
 	if (rc)
 		kfree_skb(skb);