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.
Metrics
Affected Vendors & Products
References
History
Sat, 12 Apr 2025 03:00:00 +0000
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References |
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Metrics |
threat_severity
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threat_severity
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Thu, 10 Apr 2025 16:30:00 +0000
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First Time appeared |
Linux
Linux linux Kernel |
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Weaknesses | CWE-125 | |
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc7:*:*:*:*:*:* |
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Vendors & Products |
Linux
Linux linux Kernel |
|
Metrics |
cvssV3_1
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Fri, 04 Apr 2025 02:15:00 +0000
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References |
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Thu, 03 Apr 2025 07:30:00 +0000
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Description | 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. | |
Title | can: ucan: fix out of bound read in strscpy() source | |
References |
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Status: PUBLISHED
Assigner: Linux
Published: 2025-04-03T07:19:05.403Z
Updated: 2025-05-04T07:27:14.151Z
Reserved: 2024-12-29T08:45:45.802Z
Link: CVE-2025-22003

No data.

Status : Analyzed
Published: 2025-04-03T08:15:15.840
Modified: 2025-04-10T16:13:15.503
Link: CVE-2025-22003
