net/mptcp/pm_netlink.c | 68 ++++++++++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 31 deletions(-)
This is a note to let you know that I've just added the patch titled
mptcp: pm: avoid possible UaF when selecting endp
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mptcp-pm-avoid-possible-uaf-when-selecting-endp.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
From stable+bounces-73002-greg=kroah.com@vger.kernel.org Wed Sep 4 12:58:37 2024
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Wed, 4 Sep 2024 12:57:22 +0200
Subject: mptcp: pm: avoid possible UaF when selecting endp
To: stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc: MPTCP Upstream <mptcp@lists.linux.dev>, "Matthieu Baerts (NGI0)" <matttbe@kernel.org>, Paolo Abeni <pabeni@redhat.com>, Mat Martineau <martineau@kernel.org>, Jakub Kicinski <kuba@kernel.org>
Message-ID: <20240904105721.4075460-2-matttbe@kernel.org>
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
commit 48e50dcbcbaaf713d82bf2da5c16aeced94ad07d upstream.
select_local_address() and select_signal_address() both select an
endpoint entry from the list inside an RCU protected section, but return
a reference to it, to be read later on. If the entry is dereferenced
after the RCU unlock, reading info could cause a Use-after-Free.
A simple solution is to copy the required info while inside the RCU
protected section to avoid any risk of UaF later. The address ID might
need to be modified later to handle the ID0 case later, so a copy seems
OK to deal with.
Reported-by: Paolo Abeni <pabeni@redhat.com>
Closes: https://lore.kernel.org/45cd30d3-7710-491c-ae4d-a1368c00beb1@redhat.com
Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-14-38035d40de5b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in pm_netlink.c, because the context has been modified in
commit b9d69db87fb7 ("mptcp: let the in-kernel PM use mixed IPv4 and
IPv6 addresses"), which is not a candidate for the backports. The same
modifications have been applied in this version. The conflict in
mptcp_pm_create_subflow_or_signal_addr() has been resolved by taking
the newer version, which skip a lock if it is not needed. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/mptcp/pm_netlink.c | 68 ++++++++++++++++++++++++++-----------------------
1 file changed, 37 insertions(+), 31 deletions(-)
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -150,12 +150,14 @@ static bool lookup_subflow_by_daddr(cons
return false;
}
-static struct mptcp_pm_addr_entry *
+static bool
select_local_address(const struct pm_nl_pernet *pernet,
- const struct mptcp_sock *msk)
+ const struct mptcp_sock *msk,
+ struct mptcp_pm_addr_entry *new_entry)
{
const struct sock *sk = (const struct sock *)msk;
- struct mptcp_pm_addr_entry *entry, *ret = NULL;
+ struct mptcp_pm_addr_entry *entry;
+ bool found = false;
msk_owned_by_me(msk);
@@ -177,17 +179,21 @@ select_local_address(const struct pm_nl_
continue;
}
- ret = entry;
+ *new_entry = *entry;
+ found = true;
break;
}
rcu_read_unlock();
- return ret;
+
+ return found;
}
-static struct mptcp_pm_addr_entry *
-select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk)
+static bool
+select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk,
+ struct mptcp_pm_addr_entry *new_entry)
{
- struct mptcp_pm_addr_entry *entry, *ret = NULL;
+ struct mptcp_pm_addr_entry *entry;
+ bool found = false;
rcu_read_lock();
/* do not keep any additional per socket state, just signal
@@ -202,11 +208,13 @@ select_signal_address(struct pm_nl_perne
if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
continue;
- ret = entry;
+ *new_entry = *entry;
+ found = true;
break;
}
rcu_read_unlock();
- return ret;
+
+ return found;
}
unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
@@ -527,9 +535,10 @@ __lookup_addr(struct pm_nl_pernet *perne
static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
{
- struct mptcp_pm_addr_entry *local, *signal_and_subflow = NULL;
struct sock *sk = (struct sock *)msk;
+ struct mptcp_pm_addr_entry local;
unsigned int add_addr_signal_max;
+ bool signal_and_subflow = false;
unsigned int local_addr_max;
struct pm_nl_pernet *pernet;
unsigned int subflows_max;
@@ -580,23 +589,22 @@ static void mptcp_pm_create_subflow_or_s
if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
return;
- local = select_signal_address(pernet, msk);
- if (!local)
+ if (!select_signal_address(pernet, msk, &local))
goto subflow;
/* If the alloc fails, we are on memory pressure, not worth
* continuing, and trying to create subflows.
*/
- if (!mptcp_pm_alloc_anno_list(msk, &local->addr))
+ if (!mptcp_pm_alloc_anno_list(msk, &local.addr))
return;
- __clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+ __clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
msk->pm.add_addr_signaled++;
- mptcp_pm_announce_addr(msk, &local->addr, false);
+ mptcp_pm_announce_addr(msk, &local.addr, false);
mptcp_pm_nl_addr_send_ack(msk);
- if (local->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
- signal_and_subflow = local;
+ if (local.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
+ signal_and_subflow = true;
}
subflow:
@@ -607,24 +615,22 @@ subflow:
bool fullmesh;
int i, nr;
- if (signal_and_subflow) {
- local = signal_and_subflow;
- signal_and_subflow = NULL;
- } else {
- local = select_local_address(pernet, msk);
- if (!local)
- break;
- }
+ if (signal_and_subflow)
+ signal_and_subflow = false;
+ else if (!select_local_address(pernet, msk, &local))
+ break;
- fullmesh = !!(local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
+ fullmesh = !!(local.flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
msk->pm.local_addr_used++;
- nr = fill_remote_addresses_vec(msk, &local->addr, fullmesh, addrs);
- if (nr)
- __clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
+ __clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
+ nr = fill_remote_addresses_vec(msk, &local.addr, fullmesh, addrs);
+ if (nr == 0)
+ continue;
+
spin_unlock_bh(&msk->pm.lock);
for (i = 0; i < nr; i++)
- __mptcp_subflow_connect(sk, &local->addr, &addrs[i]);
+ __mptcp_subflow_connect(sk, &local.addr, &addrs[i]);
spin_lock_bh(&msk->pm.lock);
}
mptcp_pm_nl_check_work_pending(msk);
Patches currently in stable-queue which might be from matttbe@kernel.org are
queue-6.1/mptcp-pm-fix-rm_addr-id-for-the-initial-subflow.patch
queue-6.1/selftests-mptcp-join-validate-fullmesh-endp-on-1st-sf.patch
queue-6.1/mptcp-pm-fix-id-0-endp-usage-after-multiple-re-creations.patch
queue-6.1/mptcp-make-pm_remove_addrs_and_subflows-static.patch
queue-6.1/mptcp-pm-avoid-possible-uaf-when-selecting-endp.patch
queue-6.1/mptcp-pm-reuse-id-0-after-delete-and-re-add.patch
queue-6.1/selftests-mptcp-join-check-re-adding-init-endp-with-id.patch
queue-6.1/selftests-mptcp-join-test-for-flush-re-add-endpoints.patch
queue-6.1/selftests-mptcp-add-explicit-test-case-for-remove-re.patch
queue-6.1/selftests-mptcp-add-explicit-test-case-for-remove-readd.patch
queue-6.1/selftests-mptcp-join-check-re-adding-init-endp-with-.patch
queue-6.1/selftests-mptcp-join-check-re-using-id-of-closed-subflow.patch
queue-6.1/mptcp-pm-fullmesh-select-the-right-id-later.patch
queue-6.1/mptcp-pr_debug-add-missing-n-at-the-end.patch
queue-6.1/selftests-mptcp-join-check-re-using-id-of-unused-add.patch
queue-6.1/selftests-mptcp-join-check-re-using-id-of-unused-add_addr.patch© 2016 - 2024 Red Hat, Inc.