From bippy-d175d3acf727 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47549: sata_fsl: fix UAF in sata_fsl_port_stop when rmmod sata_fsl Description =========== In the Linux kernel, the following vulnerability has been resolved: sata_fsl: fix UAF in sata_fsl_port_stop when rmmod sata_fsl When the `rmmod sata_fsl.ko` command is executed in the PPC64 GNU/Linux, a bug is reported: ================================================================== BUG: Unable to handle kernel data access on read at 0x80000800805b502c Oops: Kernel access of bad area, sig: 11 [#1] NIP [c0000000000388a4] .ioread32+0x4/0x20 LR [80000000000c6034] .sata_fsl_port_stop+0x44/0xe0 [sata_fsl] Call Trace: .free_irq+0x1c/0x4e0 (unreliable) .ata_host_stop+0x74/0xd0 [libata] .release_nodes+0x330/0x3f0 .device_release_driver_internal+0x178/0x2c0 .driver_detach+0x64/0xd0 .bus_remove_driver+0x70/0xf0 .driver_unregister+0x38/0x80 .platform_driver_unregister+0x14/0x30 .fsl_sata_driver_exit+0x18/0xa20 [sata_fsl] .__se_sys_delete_module+0x1ec/0x2d0 .system_call_exception+0xfc/0x1f0 system_call_common+0xf8/0x200 ================================================================== The triggering of the BUG is shown in the following stack: driver_detach device_release_driver_internal __device_release_driver drv->remove(dev) --> platform_drv_remove/platform_remove drv->remove(dev) --> sata_fsl_remove iounmap(host_priv->hcr_base); <---- unmap kfree(host_priv); <---- free devres_release_all release_nodes dr->node.release(dev, dr->data) --> ata_host_stop ap->ops->port_stop(ap) --> sata_fsl_port_stop ioread32(hcr_base + HCONTROL) <---- UAF host->ops->host_stop(host) The iounmap(host_priv->hcr_base) and kfree(host_priv) functions should not be executed in drv->remove. These functions should be executed in host_stop after port_stop. Therefore, we move these functions to the new function sata_fsl_host_stop and bind the new function to host_stop. The Linux kernel CVE team has assigned CVE-2021-47549 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 4.4.294 with commit cdcd80292106 Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 4.9.292 with commit 91ba94d3f7af Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 4.14.257 with commit 325ea49fc43c Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 4.19.220 with commit 0769449b0a5e Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 5.4.164 with commit 77393806c76b Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 5.10.84 with commit 4a46b2f5dce0 Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 5.15.7 with commit adf098e2a8a1 Issue introduced in 2.6.24 with commit faf0b2e5afe7 and fixed in 5.16 with commit 6c8ad7e8cf29 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-2021-47549 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/ata/sata_fsl.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/cdcd80292106df5cda325426e96495503e41f947 https://git.kernel.org/stable/c/91ba94d3f7afca195b224f77a72044fbde1389ce https://git.kernel.org/stable/c/325ea49fc43cbc03a5e1e37de8f0ca6357ced4b1 https://git.kernel.org/stable/c/0769449b0a5eabc3545337217ae690e46673e73a https://git.kernel.org/stable/c/77393806c76b6b44f1c44bd957788c8bd9152c45 https://git.kernel.org/stable/c/4a46b2f5dce02539e88a300800812bd24a45e097 https://git.kernel.org/stable/c/adf098e2a8a1e1fc075d6a5ba2edd13cf7189082 https://git.kernel.org/stable/c/6c8ad7e8cf29eb55836e7a0215f967746ab2b504