cxl/port: Fix use after free of parent_port in cxl_detach_ep()
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | affected |
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Configuration 1 [-]
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No data.
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| Linux | Linux Kernel |
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| Source | ID | Title |
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Debian DSA |
DSA-6238-1 | linux security update |
Ubuntu USN |
USN-8567-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8574-1 | Linux kernel (GCP FIPS) vulnerabilities |
Ubuntu USN |
USN-8574-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8595-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-8596-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8595-2 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8606-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8607-1 | Linux kernel (Azure CVM) vulnerabilities |
Ubuntu USN |
USN-8608-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8609-1 | Linux kernel (Azure CVM) vulnerabilities |
Ubuntu USN |
USN-8574-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8595-3 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8619-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-8665-1 | Linux kernel (Raspberry Pi) vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.159% probability within 30 days)
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ssvc
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| CPEs | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
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cvssV3_1
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cvssV3_1
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| Weaknesses | CWE-416 |
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threat_severity
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cvssV3_1
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| Description | In the Linux kernel, the following vulnerability has been resolved: cxl/port: Fix use after free of parent_port in cxl_detach_ep() cxl_detach_ep() is called during bottom-up removal when all CXL memory devices beneath a switch port have been removed. For each port in the hierarchy it locks both the port and its parent, removes the endpoint, and if the port is now empty, marks it dead and unregisters the port by calling delete_switch_port(). There are two places during this work where the parent_port may be used after freeing: First, a concurrent detach may have already processed a port by the time a second worker finds it via bus_find_device(). Without pinning parent_port, it may already be freed when we discover port->dead and attempt to unlock the parent_port. In a production kernel that's a silent memory corruption, with lock debug, it looks like this: []DEBUG_LOCKS_WARN_ON(__owner_task(owner) != get_current()) []WARNING: kernel/locking/mutex.c:949 at __mutex_unlock_slowpath+0x1ee/0x310 []Call Trace: []mutex_unlock+0xd/0x20 []cxl_detach_ep+0x180/0x400 [cxl_core] []devm_action_release+0x10/0x20 []devres_release_all+0xa8/0xe0 []device_unbind_cleanup+0xd/0xa0 []really_probe+0x1a6/0x3e0 Second, delete_switch_port() releases three devm actions registered against parent_port. The last of those is unregister_port() and it calls device_unregister() on the child port, which can cascade. If parent_port is now also empty the device core may unregister and free it too. So by the time delete_switch_port() returns, parent_port may be free, and the subsequent device_unlock(&parent_port->dev) operates on freed memory. The kernel log looks same as above, with a different offset in cxl_detach_ep(). Both of these issues stem from the absence of a lifetime guarantee between a child port and its parent port. Establish a lifetime rule for ports: child ports hold a reference to their parent device until release. Take the reference when the port is allocated and drop it when released. This ensures the parent is valid for the full lifetime of the child and eliminates the use after free window in cxl_detach_ep(). This is easily reproduced with a reload of cxl_acpi in QEMU with CXL devices present. | |
| Title | cxl/port: Fix use after free of parent_port in cxl_detach_ep() | |
| First Time appeared |
Linux
Linux linux Kernel |
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| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
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| References |
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