CVE-2021-47528

Summary

In the Linux kernel, the following vulnerability has been resolved:

usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

In cdnsp_endpoint_init(), cdnsp_ring_alloc() is assigned to pep->ring and there is a dereference of it in cdnsp_endpoint_init(), which could lead to a NULL pointer dereference on failure of cdnsp_ring_alloc().

Fix this bug by adding a check of pep->ring.

This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs.

Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug.

Builds with CONFIG_USB_CDNSP_GADGET=y show no new warnings, and our static analyzer no longer warns about this code.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux3d82904559f4f5a2622db1b21de3edf2eded7664 < 7d94bc8e335cb33918e52efdbe192c36707bfa24affected
LinuxLinux3d82904559f4f5a2622db1b21de3edf2eded7664 < 37307f7020ab38dde0892a578249bf63d00bca64affected
LinuxLinux5.12affected
LinuxLinux0 < 5.12unaffected
LinuxLinux5.15.7 <= 5.15.*unaffected
LinuxLinux5.16 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References