From: Henry Ptasinski <hptasinski@google.com>
Date: Sat, 19 Sep 2020 00:12:11 +0000
Subject: net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant
Git-commit: fe81d9f6182d1160e625894eecb3d7ff0222cac5
Patch-mainline: 5.9-rc7
References: networking-stable-20_09_24
When calculating ancestor_size with IPv6 enabled, simply using
sizeof(struct ipv6_pinfo) doesn't account for extra bytes needed for
alignment in the struct sctp6_sock. On x86, there aren't any extra
bytes, but on ARM the ipv6_pinfo structure is aligned on an 8-byte
boundary so there were 4 pad bytes that were omitted from the
ancestor_size calculation. This would lead to corruption of the
pd_lobby pointers, causing an oops when trying to free the sctp
structure on socket close.
Fixes: 636d25d557d1 ("sctp: not copy sctp_sock pd_lobby in sctp_copy_descendant")
Signed-off-by: Henry Ptasinski <hptasinski@google.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
include/net/sctp/structs.h | 8 +++++---
net/sctp/socket.c | 9 +++------
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index b33f1aefad09..0bdff38eb4bb 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -226,12 +226,14 @@ struct sctp_sock {
data_ready_signalled:1;
atomic_t pd_mode;
+
+ /* Fields after this point will be skipped on copies, like on accept
+ * and peeloff operations
+ */
+
/* Receive to here while partial delivery is in effect. */
struct sk_buff_head pd_lobby;
- /* These must be the last fields, as they will skipped on copies,
- * like on accept and peeloff operations
- */
struct list_head auto_asconf_list;
int do_auto_asconf;
};
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 836615f71a7d..53d0a4161df3 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -9220,13 +9220,10 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
static inline void sctp_copy_descendant(struct sock *sk_to,
const struct sock *sk_from)
{
- int ancestor_size = sizeof(struct inet_sock) +
- sizeof(struct sctp_sock) -
- offsetof(struct sctp_sock, pd_lobby);
-
- if (sk_from->sk_family == PF_INET6)
- ancestor_size += sizeof(struct ipv6_pinfo);
+ size_t ancestor_size = sizeof(struct inet_sock);
+ ancestor_size += sk_from->sk_prot->obj_size;
+ ancestor_size -= offsetof(struct sctp_sock, pd_lobby);
__inet_sk_copy_descendant(sk_to, sk_from, ancestor_size);
}
--
2.29.0