* [PATCH] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant
@ 2020-09-18 1:56 Henry Ptasinski
2020-09-18 13:29 ` Marcelo Ricardo Leitner
0 siblings, 1 reply; 5+ messages in thread
From: Henry Ptasinski @ 2020-09-18 1:56 UTC (permalink / raw)
To: linux-sctp, netdev
Cc: Vlad Yasevich, Neil Horman, Marcelo Ricardo Leitner,
David S . Miller, Jakub Kicinski, Corey Minyard, Henry Ptasinski
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.
Signed-off-by: Henry Ptasinski <hptasinski@google.com>
---
net/sctp/socket.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 836615f71a7d..a6358c81f087 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -9220,12 +9220,14 @@ 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);
+ size_t ancestor_size = sizeof(struct inet_sock);
if (sk_from->sk_family = PF_INET6)
- ancestor_size += sizeof(struct ipv6_pinfo);
+ ancestor_size += sizeof(struct sctp6_sock);
+ else
+ ancestor_size += sizeof(struct sctp_sock);
+
+ ancestor_size -= offsetof(struct sctp_sock, pd_lobby);
__inet_sk_copy_descendant(sk_to, sk_from, ancestor_size);
}
--
2.28.0.681.g6f77f65b4e-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant
2020-09-18 1:56 [PATCH] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant Henry Ptasinski
@ 2020-09-18 13:29 ` Marcelo Ricardo Leitner
2020-09-19 0:12 ` [PATCH v2] " Henry Ptasinski
0 siblings, 1 reply; 5+ messages in thread
From: Marcelo Ricardo Leitner @ 2020-09-18 13:29 UTC (permalink / raw)
To: Henry Ptasinski
Cc: linux-sctp, netdev, Vlad Yasevich, Neil Horman, David S . Miller,
Jakub Kicinski, Corey Minyard
On Fri, Sep 18, 2020 at 01:56:10AM +0000, Henry Ptasinski wrote:
> 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.
Makes sense.
>
> Signed-off-by: Henry Ptasinski <hptasinski@google.com>
Please add a:
Fixes: 636d25d557d1 ("sctp: not copy sctp_sock pd_lobby in sctp_copy_descendant")
> ---
> net/sctp/socket.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 836615f71a7d..a6358c81f087 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -9220,12 +9220,14 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
> static inline void sctp_copy_descendant(struct sock *sk_to,
^^^^^^ I'll send a patch to fix/remove this.
> const struct sock *sk_from)
> {
> - int ancestor_size = sizeof(struct inet_sock) +
> - sizeof(struct sctp_sock) -
> - offsetof(struct sctp_sock, pd_lobby);
^^^^^^^^
Then, as this patch is actually fixing the aforementioned commit,
please also update the comment on sctp_sock definition, as pd_lobby
now is also skipped.
> + size_t ancestor_size = sizeof(struct inet_sock);
>
> if (sk_from->sk_family = PF_INET6)
> - ancestor_size += sizeof(struct ipv6_pinfo);
> + ancestor_size += sizeof(struct sctp6_sock);
As you probably noticed by the build bot email already, there need to
be some protection to building without IPv6 enabled.
To avoid ifdefs here, something similar to how
inet_sk_copy_descendant() is done is probably welcomed, but please
feel free to be creative. :-)
> + else
> + ancestor_size += sizeof(struct sctp_sock);
> +
> + ancestor_size -= offsetof(struct sctp_sock, pd_lobby);
>
> __inet_sk_copy_descendant(sk_to, sk_from, ancestor_size);
> }
> --
> 2.28.0.681.g6f77f65b4e-goog
>
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v2] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant
2020-09-18 13:29 ` Marcelo Ricardo Leitner
@ 2020-09-19 0:12 ` Henry Ptasinski
2020-09-19 2:05 ` Marcelo Ricardo Leitner
2020-09-20 21:16 ` David Miller
0 siblings, 2 replies; 5+ messages in thread
From: Henry Ptasinski @ 2020-09-19 0:12 UTC (permalink / raw)
To: Marcelo Ricardo Leitner
Cc: linux-sctp, netdev, Vlad Yasevich, Neil Horman, David S . Miller,
Jakub Kicinski, Corey Minyard, Henry Ptasinski
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>
---
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);
}
--
2.28.0.681.g6f77f65b4e-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant
2020-09-19 0:12 ` [PATCH v2] " Henry Ptasinski
@ 2020-09-19 2:05 ` Marcelo Ricardo Leitner
2020-09-20 21:16 ` David Miller
1 sibling, 0 replies; 5+ messages in thread
From: Marcelo Ricardo Leitner @ 2020-09-19 2:05 UTC (permalink / raw)
To: Henry Ptasinski
Cc: linux-sctp, netdev, Vlad Yasevich, Neil Horman, David S . Miller,
Jakub Kicinski, Corey Minyard
On Sat, Sep 19, 2020 at 12:12:11AM +0000, Henry Ptasinski wrote:
> 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>
...
> {
> - 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;
Heh, of course. Nice one.
> + ancestor_size -= offsetof(struct sctp_sock, pd_lobby);
> __inet_sk_copy_descendant(sk_to, sk_from, ancestor_size);
> }
>
> --
> 2.28.0.681.g6f77f65b4e-goog
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant
2020-09-19 0:12 ` [PATCH v2] " Henry Ptasinski
2020-09-19 2:05 ` Marcelo Ricardo Leitner
@ 2020-09-20 21:16 ` David Miller
1 sibling, 0 replies; 5+ messages in thread
From: David Miller @ 2020-09-20 21:16 UTC (permalink / raw)
To: hptasinski
Cc: marcelo.leitner, linux-sctp, netdev, vyasevich, nhorman, kuba, cminyard
From: Henry Ptasinski <hptasinski@google.com>
Date: Sat, 19 Sep 2020 00:12:11 +0000
> 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>
Applied and queued up for -stable, thank you.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2020-09-18 1:56 [PATCH] net: sctp: Fix IPv6 ancestor_size calc in sctp_copy_descendant Henry Ptasinski
2020-09-18 13:29 ` Marcelo Ricardo Leitner
2020-09-19 0:12 ` [PATCH v2] " Henry Ptasinski
2020-09-19 2:05 ` Marcelo Ricardo Leitner
2020-09-20 21:16 ` David Miller
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