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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , Oliver Hartkopp , Marc Kleine-Budde , Alexander Aring , Stefan Schmidt , Miquel Raynal , David Ahern , Willem de Bruijn , linux-bluetooth@vger.kernel.org, linux-can@vger.kernel.org, linux-wpan@vger.kernel.org Cc: kernel-team@cloudflare.com, kuniyu@amazon.com, alibuda@linux.alibaba.com, Ignat Korchagin Subject: [PATCH v2 0/8] do not leave dangling sk pointers in pf->create functions Date: Mon, 7 Oct 2024 22:34:54 +0100 Message-Id: <20241007213502.28183-1-ignat@cloudflare.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Some protocol family create() implementations have an error path after allocating the sk object and calling sock_init_data(). sock_init_data() attaches the allocated sk object to the sock object, provided by the caller. If the create() implementation errors out after calling sock_init_data(), it releases the allocated sk object, but the caller ends up having a dangling sk pointer in its sock object on return. Subsequent manipulations on this sock object may try to access the sk pointer, because it is not NULL thus creating a use-after-free scenario. While the first patch in the series should be enough to handle this scenario Eric Dumazet suggested that it would be a good idea to refactor the code for the af_packet implementation to avoid the error path, which leaves a dangling pointer, because it may be better for some tools like kmemleak. I went a bit further and tried to actually fix all the implementations, which could potentially leave a dangling sk pointer. Changes in V2: * reverted the change introduced in 6cd4a78d962b ("net: do not leave a dangling sk pointer, when socket creation fails") * added optional commits to all pf->create implementaions to clear the sk pointer on error after sock_init_data() Ignat Korchagin (8): net: explicitly clear the sk pointer, when pf->create fails af_packet: avoid erroring out after sock_init_data() in packet_create() Bluetooth: L2CAP: do not leave dangling sk pointer on error in l2cap_sock_create() Bluetooth: RFCOMM: avoid leaving dangling sk pointer in rfcomm_sock_alloc() net: af_can: do not leave a dangling sk pointer in can_create() net: ieee802154: do not leave a dangling sk pointer in ieee802154_create() net: inet: do not leave a dangling sk pointer in inet_create() inet6: do not leave a dangling sk pointer in inet6_create() net/bluetooth/l2cap_sock.c | 1 + net/bluetooth/rfcomm/sock.c | 10 +++++----- net/can/af_can.c | 1 + net/core/sock.c | 3 --- net/ieee802154/socket.c | 12 +++++++----- net/ipv4/af_inet.c | 22 ++++++++++------------ net/ipv6/af_inet6.c | 22 ++++++++++------------ net/packet/af_packet.c | 12 ++++++------ net/socket.c | 7 ++++++- 9 files changed, 46 insertions(+), 44 deletions(-)