CVE-2021-47475

Summary

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

comedi: vmk80xx: fix transfer-buffer overflows

The driver uses endpoint-sized USB transfer buffers but up until recently had no sanity checks on the sizes.

Commit e1f13c879a7c ("staging: comedi: check validity of wMaxPacketSize of usb endpoints found") inadvertently fixed NULL-pointer dereferences when accessing the transfer buffers in case a malicious device has a zero wMaxPacketSize.

Make sure to allocate buffers large enough to handle also the other accesses that are done without a size check (e.g. byte 18 in vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond the buffers, for example, when doing descriptor fuzzing.

The original driver was for a low-speed device with 8-byte buffers. Support was later added for a device that uses bulk transfers and is presumably a full-speed device with a maximum 64-byte wMaxPacketSize.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 5229159f1d052821007aff1a1beb7873eacf1a9faffected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < ec85bcff4ed09260243d8f39faba99e1041718baaffected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 40d2a7e278e2e7c0a5fd7e997e7eb63945bf93f7affected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 7a2021b896de1ad559d33b5c5cdd20b982242088affected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 199acd8c110e3ae62833c24f632b0bb1c9f012a9affected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 33d7a470730dfe7c9bfc8da84575cf2cedd60d00affected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 278484ae93297b1bb1ce755f9d3b6d95a48c7d47affected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < 06ac746d57e6d32b062e220415c607b7e2e0fa50affected
LinuxLinux985cafccbf9b7f862aa1c5ee566801e18b5161fb < a23461c47482fc232ffc9b819539d1f837adf2b1affected
LinuxLinux2.6.31affected
LinuxLinux0 < 2.6.31unaffected
LinuxLinux4.4.292 <= 4.4.*unaffected
LinuxLinux4.9.290 <= 4.9.*unaffected
LinuxLinux4.14.255 <= 4.14.*unaffected
LinuxLinux4.19.217 <= 4.19.*unaffected
LinuxLinux5.4.159 <= 5.4.*unaffected
LinuxLinux5.10.79 <= 5.10.*unaffected
LinuxLinux5.14.18 <= 5.14.*unaffected
LinuxLinux5.15.2 <= 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