bpf: Fix a sdiv overflow issue
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a sdiv overflow issue Zac Ecob reported a problem where a bpf program may cause kernel crash due to the following error: Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI The failure is due to the below signed divide: LLONG_MIN/-1 where LLONG_MIN equals to -9,223,372,036,854,775,808. LLONG_MIN/-1 is supposed to give a positive number 9,223,372,036,854,775,808, but it is impossible since for 64-bit system, the maximum positive number is 9,223,372,036,854,775,807. On x86_64, LLONG_MIN/-1 will cause a kernel exception. On arm64, the result for LLONG_MIN/-1 is LLONG_MIN. Further investigation found all the following sdiv/smod cases may trigger an exception when bpf program is running on x86_64 platform: - LLONG_MIN/-1 for 64bit operation - INT_MIN/-1 for 32bit operation - LLONG_MIN%-1 for 64bit operation - INT_MIN%-1 for 32bit operation where -1 can be an immediate or in a register. On arm64, there are no exceptions: - LLONG_MIN/-1 = LLONG_MIN - INT_MIN/-1 = INT_MIN - LLONG_MIN%-1 = 0 - INT_MIN%-1 = 0 where -1 can be an immediate or in a register. Insn patching is needed to handle the above cases and the patched codes produced results aligned with above arm64 result. The below are pseudo codes to handle sdiv/smod exceptions including both divisor -1 and divisor 0 and the divisor is stored in a register. sdiv: tmp = rX tmp += 1 /* [-1, 0] -> [0, 1] if tmp >(unsigned) 1 goto L2 if tmp == 0 goto L1 rY = 0
CVE-2024-49888
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-2024-49888
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": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "45f2bbe7bc08d716a07a40025c672cad93180903",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "4902a6a0dc593c82055fc8c9ada371bafe26c9cc",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "d22e45a369afc7c28f11acfa5b5e8e478227ca5d",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "7dd34d7b7dcf9309fc6224caf4dd5b35bedddcb7",
"versionType": "git"
}
],
"programFiles": [
"kernel/bpf/verifier.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.10.14",
"versionType": "semver",
"lessThanOrEqual": "6.10.*"
},
{
"status": "unaffected",
"version": "6.11.3",
"versionType": "semver",
"lessThanOrEqual": "6.11.*"
},
{
"status": "unaffected",
"version": "6.12",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/bpf/verifier.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2024-49888
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #45908 · Revision 1
- Added to Heist Feed
- Publisher date