ptp: netc: fix period truncation and potential divide-by-zero in PEROUT
In the Linux kernel, the following vulnerability has been resolved: ptp: netc: fix period truncation and potential divide-by-zero in PEROUT The max_period bound in net_timer_enable_perout() was computed as: max_period = (u64)NETC_TMR_DEFAULT_FIPER + integral_period; which exceeds U32_MAX when integral_period > 0 (e.g. 0x100000002 for the default 333333333 Hz clock). A period_ns that passes this check but exceeds U32_MAX is then silently truncated when stored into the u32 struct netc_pp::period field. A truncated value of zero can reach netc_timer_set_perout_alarm(), where the local u32 period variable would also be 0, causing a divide-by-zero in roundup_u64(delta, period) whenever the stime < min_time branch is taken (which always happens for a start time of {0, 0}). Additionally, netc_timer_enable_periodic_pulse() and netc_timer_enable_fiper() both compute: fiper = pp->period - integral_period; A zero pp->period results in an unsigned wraparound to 0xFFFFFFFD, mis-programming the FIPER hardware register. Fix all three issues by capping max_period at NETC_TMR_DEFAULT_FIPER (0xFFFFFFFF). This ensures that any period_ns passing the range check fits in a u32 without truncation, so the stored value is always valid and non-zero. The accepted range is reduced by integral_period ns (typically only a few nanoseconds), which is negligible in practice.
CVE-2026-90100
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-90100
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "671e266835b8a87d6cc2c6db962de23783405dd8",
"lessThan": "51fe3fe0ffec033bd831c71d9bee3dee827e491c",
"versionType": "git"
},
{
"status": "affected",
"version": "671e266835b8a87d6cc2c6db962de23783405dd8",
"lessThan": "08988d1941e180f0ad30d91233cb64f3418ba23c",
"versionType": "git"
},
{
"status": "affected",
"version": "671e266835b8a87d6cc2c6db962de23783405dd8",
"lessThan": "777dbc9914b2f003f1d44af80c7a4a395c5961b2",
"versionType": "git"
}
],
"programFiles": [
"drivers/ptp/ptp_netc.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/ptp/ptp_netc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90100
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36509 · Revision 1
- Added to Heist Feed
- Publisher date