* [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing
@ 2020-07-24 6:48 ` Christoph Hellwig
0 siblings, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2020-07-24 6:48 UTC (permalink / raw)
To: marcelo.leitner, nhorman; +Cc: linux-sctp, netdev, syzbot+0e4699d000d8b874d8dc
This sockopt accepts two kinds of parameters, using struct
sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't
notice an implicit cast from the smaller (latter) struct to the bigger
one (former) when copying the data from the user space, which now leads
to an attempt to write beyond the buffer (because it assumes the storing
buffer is bigger than the parameter itself).
Fix it by allocating a sctp_sack_info on stack and filling it out based
on the small struct for the compat case.
Changelog stole from an earlier patch from Marcelo Ricardo Leitner.
Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack")
Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
net/sctp/socket.c | 50 +++++++++++++++++++++++++++--------------------
1 file changed, 29 insertions(+), 21 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 9a767f35971865..2c6f910b3afac0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2749,31 +2749,12 @@ static void sctp_apply_asoc_delayed_ack(struct sctp_sack_info *params,
* timer to expire. The default value for this is 2, setting this
* value to 1 will disable the delayed sack algorithm.
*/
-
-static int sctp_setsockopt_delayed_ack(struct sock *sk,
- struct sctp_sack_info *params,
- unsigned int optlen)
+static int __sctp_setsockopt_delayed_ack(struct sock *sk,
+ struct sctp_sack_info *params)
{
struct sctp_sock *sp = sctp_sk(sk);
struct sctp_association *asoc;
- if (optlen == sizeof(struct sctp_sack_info)) {
- if (params->sack_delay == 0 && params->sack_freq == 0)
- return 0;
- } else if (optlen == sizeof(struct sctp_assoc_value)) {
- pr_warn_ratelimited(DEPRECATED
- "%s (pid %d) "
- "Use of struct sctp_assoc_value in delayed_ack socket option.\n"
- "Use struct sctp_sack_info instead\n",
- current->comm, task_pid_nr(current));
-
- if (params->sack_delay == 0)
- params->sack_freq = 1;
- else
- params->sack_freq = 0;
- } else
- return -EINVAL;
-
/* Validate value parameter. */
if (params->sack_delay > 500)
return -EINVAL;
@@ -2821,6 +2802,33 @@ static int sctp_setsockopt_delayed_ack(struct sock *sk,
return 0;
}
+static int sctp_setsockopt_delayed_ack(struct sock *sk,
+ struct sctp_sack_info *params,
+ unsigned int optlen)
+{
+ if (optlen == sizeof(struct sctp_assoc_value)) {
+ struct sctp_assoc_value *v = (struct sctp_assoc_value *)params;
+ struct sctp_sack_info p;
+
+ pr_warn_ratelimited(DEPRECATED
+ "%s (pid %d) "
+ "Use of struct sctp_assoc_value in delayed_ack socket option.\n"
+ "Use struct sctp_sack_info instead\n",
+ current->comm, task_pid_nr(current));
+
+ p.sack_assoc_id = v->assoc_id;
+ p.sack_delay = v->assoc_value;
+ p.sack_freq = v->assoc_value ? 0 : 1;
+ return __sctp_setsockopt_delayed_ack(sk, &p);
+ }
+
+ if (optlen != sizeof(struct sctp_sack_info))
+ return -EINVAL;
+ if (params->sack_delay == 0 && params->sack_freq == 0)
+ return 0;
+ return __sctp_setsockopt_delayed_ack(sk, params);
+}
+
/* 7.1.3 Initialization Parameters (SCTP_INITMSG)
*
* Applications can specify protocol parameters for the default association
--
2.27.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing
@ 2020-07-24 6:48 ` Christoph Hellwig
0 siblings, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2020-07-24 6:48 UTC (permalink / raw)
To: marcelo.leitner, nhorman; +Cc: linux-sctp, netdev, syzbot+0e4699d000d8b874d8dc
This sockopt accepts two kinds of parameters, using struct
sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't
notice an implicit cast from the smaller (latter) struct to the bigger
one (former) when copying the data from the user space, which now leads
to an attempt to write beyond the buffer (because it assumes the storing
buffer is bigger than the parameter itself).
Fix it by allocating a sctp_sack_info on stack and filling it out based
on the small struct for the compat case.
Changelog stole from an earlier patch from Marcelo Ricardo Leitner.
Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack")
Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
net/sctp/socket.c | 50 +++++++++++++++++++++++++++--------------------
1 file changed, 29 insertions(+), 21 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 9a767f35971865..2c6f910b3afac0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2749,31 +2749,12 @@ static void sctp_apply_asoc_delayed_ack(struct sctp_sack_info *params,
* timer to expire. The default value for this is 2, setting this
* value to 1 will disable the delayed sack algorithm.
*/
-
-static int sctp_setsockopt_delayed_ack(struct sock *sk,
- struct sctp_sack_info *params,
- unsigned int optlen)
+static int __sctp_setsockopt_delayed_ack(struct sock *sk,
+ struct sctp_sack_info *params)
{
struct sctp_sock *sp = sctp_sk(sk);
struct sctp_association *asoc;
- if (optlen = sizeof(struct sctp_sack_info)) {
- if (params->sack_delay = 0 && params->sack_freq = 0)
- return 0;
- } else if (optlen = sizeof(struct sctp_assoc_value)) {
- pr_warn_ratelimited(DEPRECATED
- "%s (pid %d) "
- "Use of struct sctp_assoc_value in delayed_ack socket option.\n"
- "Use struct sctp_sack_info instead\n",
- current->comm, task_pid_nr(current));
-
- if (params->sack_delay = 0)
- params->sack_freq = 1;
- else
- params->sack_freq = 0;
- } else
- return -EINVAL;
-
/* Validate value parameter. */
if (params->sack_delay > 500)
return -EINVAL;
@@ -2821,6 +2802,33 @@ static int sctp_setsockopt_delayed_ack(struct sock *sk,
return 0;
}
+static int sctp_setsockopt_delayed_ack(struct sock *sk,
+ struct sctp_sack_info *params,
+ unsigned int optlen)
+{
+ if (optlen = sizeof(struct sctp_assoc_value)) {
+ struct sctp_assoc_value *v = (struct sctp_assoc_value *)params;
+ struct sctp_sack_info p;
+
+ pr_warn_ratelimited(DEPRECATED
+ "%s (pid %d) "
+ "Use of struct sctp_assoc_value in delayed_ack socket option.\n"
+ "Use struct sctp_sack_info instead\n",
+ current->comm, task_pid_nr(current));
+
+ p.sack_assoc_id = v->assoc_id;
+ p.sack_delay = v->assoc_value;
+ p.sack_freq = v->assoc_value ? 0 : 1;
+ return __sctp_setsockopt_delayed_ack(sk, &p);
+ }
+
+ if (optlen != sizeof(struct sctp_sack_info))
+ return -EINVAL;
+ if (params->sack_delay = 0 && params->sack_freq = 0)
+ return 0;
+ return __sctp_setsockopt_delayed_ack(sk, params);
+}
+
/* 7.1.3 Initialization Parameters (SCTP_INITMSG)
*
* Applications can specify protocol parameters for the default association
--
2.27.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing
2020-07-24 6:48 ` Christoph Hellwig
@ 2020-07-24 12:52 ` Marcelo Ricardo Leitner
-1 siblings, 0 replies; 6+ messages in thread
From: Marcelo Ricardo Leitner @ 2020-07-24 12:52 UTC (permalink / raw)
To: Christoph Hellwig
Cc: nhorman, linux-sctp, netdev, syzbot+0e4699d000d8b874d8dc
On Fri, Jul 24, 2020 at 08:48:55AM +0200, Christoph Hellwig wrote:
> This sockopt accepts two kinds of parameters, using struct
> sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't
> notice an implicit cast from the smaller (latter) struct to the bigger
> one (former) when copying the data from the user space, which now leads
> to an attempt to write beyond the buffer (because it assumes the storing
> buffer is bigger than the parameter itself).
>
> Fix it by allocating a sctp_sack_info on stack and filling it out based
> on the small struct for the compat case.
>
> Changelog stole from an earlier patch from Marcelo Ricardo Leitner.
>
> Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack")
> Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Thanks Christoph.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing
@ 2020-07-24 12:52 ` Marcelo Ricardo Leitner
0 siblings, 0 replies; 6+ messages in thread
From: Marcelo Ricardo Leitner @ 2020-07-24 12:52 UTC (permalink / raw)
To: Christoph Hellwig
Cc: nhorman, linux-sctp, netdev, syzbot+0e4699d000d8b874d8dc
On Fri, Jul 24, 2020 at 08:48:55AM +0200, Christoph Hellwig wrote:
> This sockopt accepts two kinds of parameters, using struct
> sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't
> notice an implicit cast from the smaller (latter) struct to the bigger
> one (former) when copying the data from the user space, which now leads
> to an attempt to write beyond the buffer (because it assumes the storing
> buffer is bigger than the parameter itself).
>
> Fix it by allocating a sctp_sack_info on stack and filling it out based
> on the small struct for the compat case.
>
> Changelog stole from an earlier patch from Marcelo Ricardo Leitner.
>
> Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack")
> Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Thanks Christoph.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing
2020-07-24 6:48 ` Christoph Hellwig
@ 2020-07-24 23:49 ` David Miller
-1 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2020-07-24 23:49 UTC (permalink / raw)
To: hch
Cc: marcelo.leitner, nhorman, linux-sctp, netdev,
syzbot+0e4699d000d8b874d8dc
From: Christoph Hellwig <hch@lst.de>
Date: Fri, 24 Jul 2020 08:48:55 +0200
> This sockopt accepts two kinds of parameters, using struct
> sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't
> notice an implicit cast from the smaller (latter) struct to the bigger
> one (former) when copying the data from the user space, which now leads
> to an attempt to write beyond the buffer (because it assumes the storing
> buffer is bigger than the parameter itself).
>
> Fix it by allocating a sctp_sack_info on stack and filling it out based
> on the small struct for the compat case.
>
> Changelog stole from an earlier patch from Marcelo Ricardo Leitner.
>
> Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack")
> Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Applied, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing
@ 2020-07-24 23:49 ` David Miller
0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2020-07-24 23:49 UTC (permalink / raw)
To: hch
Cc: marcelo.leitner, nhorman, linux-sctp, netdev,
syzbot+0e4699d000d8b874d8dc
From: Christoph Hellwig <hch@lst.de>
Date: Fri, 24 Jul 2020 08:48:55 +0200
> This sockopt accepts two kinds of parameters, using struct
> sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't
> notice an implicit cast from the smaller (latter) struct to the bigger
> one (former) when copying the data from the user space, which now leads
> to an attempt to write beyond the buffer (because it assumes the storing
> buffer is bigger than the parameter itself).
>
> Fix it by allocating a sctp_sack_info on stack and filling it out based
> on the small struct for the compat case.
>
> Changelog stole from an earlier patch from Marcelo Ricardo Leitner.
>
> Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack")
> Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Applied, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-07-24 23:49 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2020-07-24 6:48 [PATCH v2 net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing Christoph Hellwig
2020-07-24 6:48 ` Christoph Hellwig
2020-07-24 12:52 ` Marcelo Ricardo Leitner
2020-07-24 12:52 ` Marcelo Ricardo Leitner
2020-07-24 23:49 ` David Miller
2020-07-24 23:49 ` David Miller
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