mirror of
https://github.com/CVEProject/cvelist.git
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102 lines
5.7 KiB
JSON
102 lines
5.7 KiB
JSON
{
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"data_version": "4.0",
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"data_type": "CVE",
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"data_format": "MITRE",
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"CVE_data_meta": {
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"ID": "CVE-2021-47608",
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"ASSIGNER": "cve@kernel.org",
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"STATE": "PUBLIC"
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},
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"description": {
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"description_data": [
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{
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"lang": "eng",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix kernel address leakage in atomic fetch\n\nThe change in commit 37086bfdc737 (\"bpf: Propagate stack bounds to registers\nin atomics w/ BPF_FETCH\") around check_mem_access() handling is buggy since\nthis would allow for unprivileged users to leak kernel pointers. For example,\nan atomic fetch/and with -1 on a stack destination which holds a spilled\npointer will migrate the spilled register type into a scalar, which can then\nbe exported out of the program (since scalar != pointer) by dumping it into\na map value.\n\nThe original implementation of XADD was preventing this situation by using\na double call to check_mem_access() one with BPF_READ and a subsequent one\nwith BPF_WRITE, in both cases passing -1 as a placeholder value instead of\nregister as per XADD semantics since it didn't contain a value fetch. The\nBPF_READ also included a check in check_stack_read_fixed_off() which rejects\nthe program if the stack slot is of __is_pointer_value() if dst_regno < 0.\nThe latter is to distinguish whether we're dealing with a regular stack spill/\nfill or some arithmetical operation which is disallowed on non-scalars, see\nalso 6e7e63cbb023 (\"bpf: Forbid XADD on spilled pointers for unprivileged\nusers\") for more context on check_mem_access() and its handling of placeholder\nvalue -1.\n\nOne minimally intrusive option to fix the leak is for the BPF_FETCH case to\ninitially check the BPF_READ case via check_mem_access() with -1 as register,\nfollowed by the actual load case with non-negative load_reg to propagate\nstack bounds to registers."
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}
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]
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},
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"problemtype": {
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"problemtype_data": [
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{
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"description": [
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{
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"lang": "eng",
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"value": "n/a"
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}
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]
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}
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]
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},
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"affects": {
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"vendor": {
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"vendor_data": [
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{
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"vendor_name": "Linux",
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"product": {
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"product_data": [
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{
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"product_name": "Linux",
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"version": {
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"version_data": [
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{
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"version_affected": "<",
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"version_name": "37086bfdc737",
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"version_value": "423628125a48"
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},
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{
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"version_value": "not down converted",
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"x_cve_json_5_version_data": {
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"versions": [
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{
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"version": "5.12",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "5.12",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "5.15.11",
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"lessThanOrEqual": "5.15.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "5.16",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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],
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"defaultStatus": "affected"
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}
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}
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]
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}
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}
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]
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}
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}
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]
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}
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},
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"references": {
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"reference_data": [
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{
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"url": "https://git.kernel.org/stable/c/423628125a484538111c2c6d9bb1588eb086053b",
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"refsource": "MISC",
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"name": "https://git.kernel.org/stable/c/423628125a484538111c2c6d9bb1588eb086053b"
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},
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{
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"url": "https://git.kernel.org/stable/c/7d3baf0afa3aa9102d6a521a8e4c41888bb79882",
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"refsource": "MISC",
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"name": "https://git.kernel.org/stable/c/7d3baf0afa3aa9102d6a521a8e4c41888bb79882"
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}
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]
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},
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"generator": {
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"engine": "bippy-9e1c9544281a"
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}
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} |