From: Chengfeng Ye cyeaa@connect.ust.hk
stable inclusion from stable-v5.10.115 commit e757ff4bbc893bc030c2d10143091094da73b9ff category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5IZ9C
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
commit b7c81f80246fac44077166f3e07103affe6db8ff upstream.
&e->event and e point to the same address, and &e->event could be freed in queue_event. So there is a potential uaf issue if we dereference e after calling queue_event(). Fix this by adding a temporary variable to maintain e->client in advance, this can avoid the potential uaf issue.
Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye cyeaa@connect.ust.hk Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp Link: https://lore.kernel.org/r/20220409041243.603210-2-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/firewire/core-cdev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c index fb6c651214f3..b0cc3f1e9bb0 100644 --- a/drivers/firewire/core-cdev.c +++ b/drivers/firewire/core-cdev.c @@ -1480,6 +1480,7 @@ static void outbound_phy_packet_callback(struct fw_packet *packet, { struct outbound_phy_packet_event *e = container_of(packet, struct outbound_phy_packet_event, p); + struct client *e_client;
switch (status) { /* expected: */ @@ -1496,9 +1497,10 @@ static void outbound_phy_packet_callback(struct fw_packet *packet, } e->phy_packet.data[0] = packet->timestamp;
+ e_client = e->client; queue_event(e->client, &e->event, &e->phy_packet, sizeof(e->phy_packet) + e->phy_packet.length, NULL, 0); - client_put(e->client); + client_put(e_client); }
static int ioctl_send_phy_packet(struct client *client, union ioctl_arg *arg)