From bippy-d175d3acf727 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47479: staging: rtl8712: fix use-after-free in rtl8712_dl_fw Description =========== In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix use-after-free in rtl8712_dl_fw Syzbot reported use-after-free in rtl8712_dl_fw(). The problem was in race condition between r871xu_dev_remove() ->ndo_open() callback. It's easy to see from crash log, that driver accesses released firmware in ->ndo_open() callback. It may happen, since driver was releasing firmware _before_ unregistering netdev. Fix it by moving unregister_netdev() before cleaning up resources. Call Trace: ... rtl871x_open_fw drivers/staging/rtl8712/hal_init.c:83 [inline] rtl8712_dl_fw+0xd95/0xe10 drivers/staging/rtl8712/hal_init.c:170 rtl8712_hal_init drivers/staging/rtl8712/hal_init.c:330 [inline] rtl871x_hal_init+0xae/0x180 drivers/staging/rtl8712/hal_init.c:394 netdev_open+0xe6/0x6c0 drivers/staging/rtl8712/os_intfs.c:380 __dev_open+0x2bc/0x4d0 net/core/dev.c:1484 Freed by task 1306: ... release_firmware+0x1b/0x30 drivers/base/firmware_loader/main.c:1053 r871xu_dev_remove+0xcc/0x2c0 drivers/staging/rtl8712/usb_intf.c:599 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458 The Linux kernel CVE team has assigned CVE-2021-47479 to this issue. Affected and fixed versions =========================== Issue introduced in 3.3 with commit 8c213fa59199 and fixed in 5.10.79 with commit c430094541a8 Issue introduced in 3.3 with commit 8c213fa59199 and fixed in 5.14.18 with commit befd23bd3b17 Issue introduced in 3.3 with commit 8c213fa59199 and fixed in 5.15.2 with commit a65c9afe9f2f Issue introduced in 3.3 with commit 8c213fa59199 and fixed in 5.16 with commit c052cc1a069c Issue introduced in 3.2.6 with commit bc5d453eab45 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2021-47479 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/staging/rtl8712/usb_intf.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/c430094541a80575259a94ff879063ef01473506 https://git.kernel.org/stable/c/befd23bd3b17f1a3f9c943a8580b47444c7c63ed https://git.kernel.org/stable/c/a65c9afe9f2f55b7a7fb4a25ab654cd4139683a4 https://git.kernel.org/stable/c/c052cc1a069c3e575619cf64ec427eb41176ca70