CVE-2021-47549

HIGH
Published May 24, 2024 Modified Jan 7, 2025 CWE-416

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.

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CVSS v3.1 Score

7.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/0769449b0a5eabc3545337217ae690e46673e73a https://git.kernel.org/stable/c/325ea49fc43cbc03a5e1e37de8f0ca6357ced4b1 https://git.kernel.org/stable/c/4a46b2f5dce02539e88a300800812bd24a45e097 https://git.kernel.org/stable/c/6c8ad7e8cf29eb55836e7a0215f967746ab2b504 https://git.kernel.org/stable/c/77393806c76b6b44f1c44bd957788c8bd9152c45 https://git.kernel.org/stable/c/91ba94d3f7afca195b224f77a72044fbde1389ce https://git.kernel.org/stable/c/adf098e2a8a1e1fc075d6a5ba2edd13cf7189082 https://git.kernel.org/stable/c/cdcd80292106df5cda325426e96495503e41f947 https://git.kernel.org/stable/c/0769449b0a5eabc3545337217ae690e46673e73a https://git.kernel.org/stable/c/325ea49fc43cbc03a5e1e37de8f0ca6357ced4b1 https://git.kernel.org/stable/c/4a46b2f5dce02539e88a300800812bd24a45e097 https://git.kernel.org/stable/c/6c8ad7e8cf29eb55836e7a0215f967746ab2b504 https://git.kernel.org/stable/c/77393806c76b6b44f1c44bd957788c8bd9152c45 https://git.kernel.org/stable/c/91ba94d3f7afca195b224f77a72044fbde1389ce https://git.kernel.org/stable/c/adf098e2a8a1e1fc075d6a5ba2edd13cf7189082 https://git.kernel.org/stable/c/cdcd80292106df5cda325426e96495503e41f947

Frequently Asked Questions

What is CVE-2021-47549? +
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. It has a CVSS v3.1 base score of 7.8 (HIGH).
How severe is CVE-2021-47549? +
CVE-2021-47549 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2021-47549? +
CVE-2021-47549 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47549? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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