From 884cf2cc957da7ac178a0e6c6c69ddfec0481cc8 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Thu, 6 Aug 2026 23:06:21 +0000 Subject: [PATCH] Bluetooth: ISO: zero the sockaddr before returning it in getname iso_sock_getname() fills a struct sockaddr_iso in place and returns its size without clearing it first, so bytes it does not write are copied to user space from the kernel stack. The getsockname(2) and getpeername(2) paths both run through do_getsockname(), which hands getname() an uninitialized sockaddr_storage on the stack and copies back up to the number of bytes getname() returns, so the driver has to initialize every byte it accounts for. Two ranges are left uninitialized: - struct sockaddr_iso is 10 bytes but only 9 are written (family, iso_bdaddr, iso_bdaddr_type), leaking the trailing pad byte on every call. - for a broadcast peer (BIS_LINK or PA_LINK) the returned length grows by sizeof(struct sockaddr_iso_bc), but only bc_sid, bc_num_bis and bc_bis are filled; bc_bdaddr and bc_bdaddr_type, the first 7 bytes of that structure, are never written. An unprivileged process can open a BTPROTO_ISO socket and reach the pad leak with getsockname(); the broadcast leak needs an established BIS/PA connection. l2cap and rfcomm already memset their sockaddr in getname for the same reason; do the same here. Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type") Fixes: 0a766a0affb5 ("Bluetooth: ISO: Fix getpeername not returning sockaddr_iso_bc fields") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/iso.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index e46242d4455d..aa2ce78f56a2 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -1536,6 +1536,7 @@ static int iso_sock_getname(struct socket *sock, struct sockaddr *addr, lock_sock(sk); + memset(sa, 0, sizeof(struct sockaddr_iso)); addr->sa_family = AF_BLUETOOTH; if (peer) { @@ -1546,6 +1547,7 @@ static int iso_sock_getname(struct socket *sock, struct sockaddr *addr, sa->iso_bdaddr_type = iso_pi(sk)->dst_type; if (hcon && (hcon->type == BIS_LINK || hcon->type == PA_LINK)) { + memset(sa->iso_bc, 0, sizeof(struct sockaddr_iso_bc)); sa->iso_bc->bc_sid = iso_pi(sk)->bc_sid; sa->iso_bc->bc_num_bis = iso_pi(sk)->bc_num_bis; memcpy(sa->iso_bc->bc_bis, iso_pi(sk)->bc_bis,