gsd-2021-47131
Vulnerability from gsd
Modified
2024-03-05 06:03
Details
In the Linux kernel, the following vulnerability has been resolved:
net/tls: Fix use-after-free after the TLS device goes down and up
When a netdev with active TLS offload goes down, tls_device_down is
called to stop the offload and tear down the TLS context. However, the
socket stays alive, and it still points to the TLS context, which is now
deallocated. If a netdev goes up, while the connection is still active,
and the data flow resumes after a number of TCP retransmissions, it will
lead to a use-after-free of the TLS context.
This commit addresses this bug by keeping the context alive until its
normal destruction, and implements the necessary fallbacks, so that the
connection can resume in software (non-offloaded) kTLS mode.
On the TX side tls_sw_fallback is used to encrypt all packets. The RX
side already has all the necessary fallbacks, because receiving
non-decrypted packets is supported. The thing needed on the RX side is
to block resync requests, which are normally produced after receiving
non-decrypted packets.
The necessary synchronization is implemented for a graceful teardown:
first the fallbacks are deployed, then the driver resources are released
(it used to be possible to have a tls_dev_resync after tls_dev_del).
A new flag called TLS_RX_DEV_DEGRADED is added to indicate the fallback
mode. It's used to skip the RX resync logic completely, as it becomes
useless, and some objects may be released (for example, resync_async,
which is allocated and freed by the driver).
Aliases
{ "gsd": { "metadata": { "exploitCode": "unknown", "remediation": "unknown", "reportConfidence": "confirmed", "type": "vulnerability" }, "osvSchema": { "aliases": [ "CVE-2021-47131" ], "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tls: Fix use-after-free after the TLS device goes down and up\n\nWhen a netdev with active TLS offload goes down, tls_device_down is\ncalled to stop the offload and tear down the TLS context. However, the\nsocket stays alive, and it still points to the TLS context, which is now\ndeallocated. If a netdev goes up, while the connection is still active,\nand the data flow resumes after a number of TCP retransmissions, it will\nlead to a use-after-free of the TLS context.\n\nThis commit addresses this bug by keeping the context alive until its\nnormal destruction, and implements the necessary fallbacks, so that the\nconnection can resume in software (non-offloaded) kTLS mode.\n\nOn the TX side tls_sw_fallback is used to encrypt all packets. The RX\nside already has all the necessary fallbacks, because receiving\nnon-decrypted packets is supported. The thing needed on the RX side is\nto block resync requests, which are normally produced after receiving\nnon-decrypted packets.\n\nThe necessary synchronization is implemented for a graceful teardown:\nfirst the fallbacks are deployed, then the driver resources are released\n(it used to be possible to have a tls_dev_resync after tls_dev_del).\n\nA new flag called TLS_RX_DEV_DEGRADED is added to indicate the fallback\nmode. It\u0027s used to skip the RX resync logic completely, as it becomes\nuseless, and some objects may be released (for example, resync_async,\nwhich is allocated and freed by the driver).", "id": "GSD-2021-47131", "modified": "2024-03-05T06:03:55.191174Z", "schema_version": "1.4.0" } }, "namespaces": { "cve.org": { "CVE_data_meta": { "ASSIGNER": "cve@kernel.org", "ID": "CVE-2021-47131", "STATE": "PUBLIC" }, "affects": { "vendor": { "vendor_data": [ { "product": { "product_data": [ { "product_name": "Linux", "version": { "version_data": [ { "version_affected": "\u003c", "version_name": "e8f69799810c", "version_value": "f1d4184f128d" }, { "version_value": "not down converted", "x_cve_json_5_version_data": { "defaultStatus": "affected", "versions": [ { "status": "affected", "version": "4.18" }, { "lessThan": "4.18", "status": "unaffected", "version": "0", "versionType": "custom" }, { "lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.43", "versionType": "custom" }, { "lessThanOrEqual": "5.12.*", "status": "unaffected", "version": "5.12.10", "versionType": "custom" }, { "lessThanOrEqual": "*", "status": "unaffected", "version": "5.13", "versionType": "original_commit_for_fix" } ] } } ] } } ] }, "vendor_name": "Linux" } ] } }, "data_format": "MITRE", "data_type": "CVE", "data_version": "4.0", "description": { "description_data": [ { "lang": "eng", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tls: Fix use-after-free after the TLS device goes down and up\n\nWhen a netdev with active TLS offload goes down, tls_device_down is\ncalled to stop the offload and tear down the TLS context. However, the\nsocket stays alive, and it still points to the TLS context, which is now\ndeallocated. If a netdev goes up, while the connection is still active,\nand the data flow resumes after a number of TCP retransmissions, it will\nlead to a use-after-free of the TLS context.\n\nThis commit addresses this bug by keeping the context alive until its\nnormal destruction, and implements the necessary fallbacks, so that the\nconnection can resume in software (non-offloaded) kTLS mode.\n\nOn the TX side tls_sw_fallback is used to encrypt all packets. The RX\nside already has all the necessary fallbacks, because receiving\nnon-decrypted packets is supported. The thing needed on the RX side is\nto block resync requests, which are normally produced after receiving\nnon-decrypted packets.\n\nThe necessary synchronization is implemented for a graceful teardown:\nfirst the fallbacks are deployed, then the driver resources are released\n(it used to be possible to have a tls_dev_resync after tls_dev_del).\n\nA new flag called TLS_RX_DEV_DEGRADED is added to indicate the fallback\nmode. It\u0027s used to skip the RX resync logic completely, as it becomes\nuseless, and some objects may be released (for example, resync_async,\nwhich is allocated and freed by the driver)." } ] }, "generator": { "engine": "bippy-8df59b4913de" }, "problemtype": { "problemtype_data": [ { "description": [ { "lang": "eng", "value": "n/a" } ] } ] }, "references": { "reference_data": [ { "name": "https://git.kernel.org/stable/c/f1d4184f128dede82a59a841658ed40d4e6d3aa2", "refsource": "MISC", "url": "https://git.kernel.org/stable/c/f1d4184f128dede82a59a841658ed40d4e6d3aa2" }, { "name": "https://git.kernel.org/stable/c/0f1e6fe66977a864fe850522316f713d7b926fd9", "refsource": "MISC", "url": "https://git.kernel.org/stable/c/0f1e6fe66977a864fe850522316f713d7b926fd9" }, { "name": "https://git.kernel.org/stable/c/c55dcdd435aa6c6ad6ccac0a4c636d010ee367a4", "refsource": "MISC", "url": "https://git.kernel.org/stable/c/c55dcdd435aa6c6ad6ccac0a4c636d010ee367a4" } ] } }, "nvd.nist.gov": { "cve": { "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tls: Fix use-after-free after the TLS device goes down and up\n\nWhen a netdev with active TLS offload goes down, tls_device_down is\ncalled to stop the offload and tear down the TLS context. However, the\nsocket stays alive, and it still points to the TLS context, which is now\ndeallocated. If a netdev goes up, while the connection is still active,\nand the data flow resumes after a number of TCP retransmissions, it will\nlead to a use-after-free of the TLS context.\n\nThis commit addresses this bug by keeping the context alive until its\nnormal destruction, and implements the necessary fallbacks, so that the\nconnection can resume in software (non-offloaded) kTLS mode.\n\nOn the TX side tls_sw_fallback is used to encrypt all packets. The RX\nside already has all the necessary fallbacks, because receiving\nnon-decrypted packets is supported. The thing needed on the RX side is\nto block resync requests, which are normally produced after receiving\nnon-decrypted packets.\n\nThe necessary synchronization is implemented for a graceful teardown:\nfirst the fallbacks are deployed, then the driver resources are released\n(it used to be possible to have a tls_dev_resync after tls_dev_del).\n\nA new flag called TLS_RX_DEV_DEGRADED is added to indicate the fallback\nmode. It\u0027s used to skip the RX resync logic completely, as it becomes\nuseless, and some objects may be released (for example, resync_async,\nwhich is allocated and freed by the driver)." } ], "id": "CVE-2021-47131", "lastModified": "2024-03-17T22:38:29.433", "metrics": {}, "published": "2024-03-15T21:15:07.623", "references": [ { "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0f1e6fe66977a864fe850522316f713d7b926fd9" }, { "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c55dcdd435aa6c6ad6ccac0a4c636d010ee367a4" }, { "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f1d4184f128dede82a59a841658ed40d4e6d3aa2" } ], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis" } } } }
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Sightings
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Nomenclature
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- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.