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CVE-2025-22003

In the Linux kernel, the following vulnerability has been resolved: can: ucan: fix out of bound read in strscpy() source Commit 7fdaf8966aae ("can: ucan: use strscpy() to instead of strncpy()") unintentionally introduced a one byte out of bound read on strscpy()'s source argument (which is kind of ironic knowing that strscpy() is meant to be a more secure alternative :)). Let's consider below buffers: dest[len + 1]; /* will be NUL terminated */ src[len]; /* may not be NUL terminated */ When doing: strncpy(dest, src, len); dest[len] = '\0'; strncpy() will read up to len bytes from src. On the other hand: strscpy(dest, src, len + 1); will read up to len + 1 bytes from src, that is to say, an out of bound read of one byte will occur on src if it is not NUL terminated. Note that the src[len] byte is never copied, but strscpy() still needs to read it to check whether a truncation occurred or not. This exact pattern happened in ucan. The root cause is that the source is not NUL terminated. Instead of doing a copy in a local buffer, directly NUL terminate it as soon as usb_control_msg() returns. With this, the local firmware_str[] variable can be removed. On top of this do a couple refactors: - ucan_ctl_payload->raw is only used for the firmware string, so rename it to ucan_ctl_payload->fw_str and change its type from u8 to char. - ucan_device_request_in() is only used to retrieve the firmware string, so rename it to ucan_get_fw_str() and refactor it to make it directly handle all the string termination logic.

Published

2025-04-03T08:15:15.840

Last Modified

2025-10-01T17:15:41.077

Status

Modified

Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Severity

CVSSv3.1: 5.5 (MEDIUM)

Weaknesses
  • Type: Primary
    CWE-125
  • Type: Secondary
    CWE-125
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System linux linux_kernel < 6.6.85 Yes
Operating System linux linux_kernel < 6.12.21 Yes
Operating System linux linux_kernel < 6.13.9 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
References