# CVE-2021-47549: linux: In the Linux kernel, the following vulnerability has been resolved:  sata_fsl: fix UAF in sata_fsl_port_stop when rmm...

CVE-2021-47549 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47549, released May 24, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47549
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 24, 2024

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.15-1 | [DEBIAN-CVE-2021-47549](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47549.md) | May 24, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.15-1 | [DEBIAN-CVE-2021-47549](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47549.md) | May 24, 2024 |
| Linux | linux Debian 14 | 5.15.15-1 | [DEBIAN-CVE-2021-47549](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47549.md) | May 24, 2024 |

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