[PATCH 1/2] Bluetooth: ISO: fix UAF in iso_recv_frame

[PATCH 1/2] Bluetooth: ISO: fix UAF in iso_recv_frame

[Muhammad Bilal]

iso_recv_frame reads conn->sk under iso_conn_lock but releases the lock
before using sk, with no reference held. A concurrent iso_sock_kill()
can free sk in that window, causing use-after-free on sk->sk_state and
sock_queue_rcv_skb().

Fix by replacing the bare pointer read with iso_sock_hold(conn), which
calls sock_hold() while the spinlock is held, atomically elevating the
refcount before the lock drops. Add a drop_put label so sock_put() is
called on all exit paths where the hold succeeded.

Fixes: ccf74f2390d60a2f9a75ef496d2564abb478f46a ("Bluetooth: Add BTPROTO_ISO socket type")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
---
 net/bluetooth/iso.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index d7af617cda45..f03b7fa5dccc 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -564,7 +564,7 @@ static void iso_recv_frame(struct iso_conn *conn, struct sk_buff *skb)
 	struct sock *sk;
 
 	iso_conn_lock(conn);
-	sk = conn->sk;
+	sk = iso_sock_hold(conn);
 	iso_conn_unlock(conn);
 
 	if (!sk)
@@ -573,11 +573,15 @@ static void iso_recv_frame(struct iso_conn *conn, struct sk_buff *skb)
 	BT_DBG("sk %p len %d", sk, skb->len);
 
 	if (sk->sk_state != BT_CONNECTED)
-		goto drop;
+		goto drop_put;
 
-	if (!sock_queue_rcv_skb(sk, skb))
+	if (!sock_queue_rcv_skb(sk, skb)) {
+		sock_put(sk);
 		return;
+	}
 
+drop_put:
+	sock_put(sk);
 drop:
 	kfree_skb(skb);
 }
-- 
2.53.0

[PATCH 2/2] Bluetooth: ISO: serialize iso_sock_clear_timer with socket lock

[Muhammad Bilal]

iso_sock_close() calls iso_sock_clear_timer() before acquiring
lock_sock(sk).

iso_sock_clear_timer() reads iso_pi(sk)->conn twice without the
socket lock held:

    if (!iso_pi(sk)->conn)
        return;
    cancel_delayed_work(&iso_pi(sk)->conn->timeout_work);

Concurrently, iso_conn_del() executes under lock_sock(sk) and calls
iso_chan_del(), which sets iso_pi(sk)->conn to NULL and may result in
the final reference to the connection being dropped:

    CPU0                         CPU1
    ----                         ----
    iso_sock_clear_timer()
      if (conn != NULL) ...      lock_sock(sk)
                                   iso_chan_del()
                                   iso_pi(sk)->conn = NULL
      cancel_delayed_work(conn)  /* NULL deref or UAF */

iso_pi(sk)->conn is not stable across the unlock window, causing a
NULL pointer dereference or use-after-free.

Serialize iso_sock_clear_timer() with the socket lock by moving it
inside lock_sock()/release_sock(), matching the pattern used in
iso_conn_del() and all other call sites.

Fixes: ccf74f2390d60a2f9a75ef496d2564abb478f46a ("Bluetooth: Add BTPROTO_ISO socket type")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
---
 net/bluetooth/iso.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index f03b7fa5dccc..876649556d3c 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -864,8 +864,8 @@ static void __iso_sock_close(struct sock *sk)
 /* Must be called on unlocked socket. */
 static void iso_sock_close(struct sock *sk)
 {
-	iso_sock_clear_timer(sk);
 	lock_sock(sk);
+	iso_sock_clear_timer(sk);
 	__iso_sock_close(sk);
 	release_sock(sk);
 	iso_sock_kill(sk);
-- 
2.53.0

RE: [1/2] Bluetooth: ISO: fix UAF in iso_recv_frame

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1042 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=1101377

---Test result---

Test Summary:
CheckPatch                    PASS      1.58 seconds
VerifyFixes                   PASS      0.13 seconds
VerifySignedoff               PASS      0.13 seconds
GitLint                       PASS      1.16 seconds
SubjectPrefix                 PASS      0.25 seconds
BuildKernel                   PASS      25.09 seconds
CheckAllWarning               PASS      27.91 seconds
CheckSparse                   PASS      26.59 seconds
BuildKernel32                 PASS      24.64 seconds
TestRunnerSetup               PASS      527.80 seconds
TestRunner_iso-tester         PASS      81.16 seconds
IncrementalBuild              PASS      26.12 seconds



https://github.com/bluez/bluetooth-next/pull/248

---
Regards,
Linux Bluetooth

Re: [PATCH 1/2] Bluetooth: ISO: fix UAF in iso_recv_frame

[patchwork-bot+bluetooth]

Hello:

This series was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Wed, 27 May 2026 04:59:17 +0000 you wrote:
> iso_recv_frame reads conn->sk under iso_conn_lock but releases the lock
> before using sk, with no reference held. A concurrent iso_sock_kill()
> can free sk in that window, causing use-after-free on sk->sk_state and
> sock_queue_rcv_skb().
> 
> Fix by replacing the bare pointer read with iso_sock_hold(conn), which
> calls sock_hold() while the spinlock is held, atomically elevating the
> refcount before the lock drops. Add a drop_put label so sock_put() is
> called on all exit paths where the hold succeeded.
> 
> [...]

Here is the summary with links:
  - [1/2] Bluetooth: ISO: fix UAF in iso_recv_frame
    https://git.kernel.org/bluetooth/bluetooth-next/c/7e3545cc3d1a
  - [2/2] Bluetooth: ISO: serialize iso_sock_clear_timer with socket lock
    https://git.kernel.org/bluetooth/bluetooth-next/c/7978ae58aafb

You are awesome, thank you!
-- 
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