diff mbox series

[v2,2/8] af_packet: avoid erroring out after sock_init_data() in packet_create()

Message ID 20241007213502.28183-3-ignat@cloudflare.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series do not leave dangling sk pointers in pf->create functions | expand

Checks

Context Check Description
netdev/series_format warning Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -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 5 maintainers
netdev/build_clang success Errors and warnings before: 6 this patch: 6
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 No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 7 this patch: 7
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 30 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

Ignat Korchagin Oct. 7, 2024, 9:34 p.m. UTC 
After sock_init_data() the allocated sk object is attached to the provided
sock object. On error, packet_create() frees the sk object leaving the
dangling pointer in the sock object on return. Some other code may try
to use this pointer and cause use-after-free.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
---
 net/packet/af_packet.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index a705ec214254..97774bd4b6cb 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3421,17 +3421,17 @@  static int packet_create(struct net *net, struct socket *sock, int protocol,
 	if (sock->type == SOCK_PACKET)
 		sock->ops = &packet_ops_spkt;
 
+	po = pkt_sk(sk);
+	err = packet_alloc_pending(po);
+	if (err)
+		goto out_sk_free;
+
 	sock_init_data(sock, sk);
 
-	po = pkt_sk(sk);
 	init_completion(&po->skb_completion);
 	sk->sk_family = PF_PACKET;
 	po->num = proto;
 
-	err = packet_alloc_pending(po);
-	if (err)
-		goto out2;
-
 	packet_cached_dev_reset(po);
 
 	sk->sk_destruct = packet_sock_destruct;
@@ -3463,7 +3463,7 @@  static int packet_create(struct net *net, struct socket *sock, int protocol,
 	sock_prot_inuse_add(net, &packet_proto, 1);
 
 	return 0;
-out2:
+out_sk_free:
 	sk_free(sk);
 out:
 	return err;