-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 OpenSSL Security Advisory [9th January 2024] ============================================ POLY1305 MAC implementation corrupts vector registers on PowerPC (CVE-2023-6129) ================================================================================ Severity: Low Issue summary: The POLY1305 MAC (message authentication code) implementation contains a bug that might corrupt the internal state of applications running on PowerPC CPU based platforms if the CPU provides vector instructions. Impact summary: If an attacker can influence whether the POLY1305 MAC algorithm is used, the application state might be corrupted with various application dependent consequences. The POLY1305 MAC (message authentication code) implementation in OpenSSL for PowerPC CPUs restores the contents of vector registers in a different order than they are saved. Thus the contents of some of these vector registers are corrupted when returning to the caller. The vulnerable code is used only on newer PowerPC processors supporting the PowerISA 2.07 instructions. The consequences of this kind of internal application state corruption can be various - from no consequences, if the calling application does not depend on the contents of non-volatile XMM registers at all, to the worst consequences, where the attacker could get complete control of the application process. However unless the compiler uses the vector registers for storing pointers, the most likely consequence, if any, would be an incorrect result of some application dependent calculations or a crash leading to a denial of service. The POLY1305 MAC algorithm is most frequently used as part of the CHACHA20-POLY1305 AEAD (authenticated encryption with associated data) algorithm. The most common usage of this AEAD cipher is with TLS protocol versions 1.2 and 1.3. If this cipher is enabled on the server a malicious client can influence whether this AEAD cipher is used. This implies that TLS server applications using OpenSSL can be potentially impacted. However we are currently not aware of any concrete application that would be affected by this issue therefore we consider this a Low severity security issue. OpenSSL versions 3.0.0 to 3.0.12, 3.1.0 to 3.1.4 and 3.2.0 are vulnerable to this issue. The FIPS provider is not affected because the POLY1305 MAC algorithm is not FIPS approved and the FIPS provider does not implement it. OpenSSL versions 1.1.1 and 1.0.2 are not affected by this issue. Due to the low severity of this issue we are not issuing new releases of OpenSSL at this time. The fix will be included in the next releases when they become available. The fix is also available in commit 5b139f95 (for 3.2), commit f3fc5808 (for 3.1) and commit 050d263 (for 3.0) in the OpenSSL git repository. This issue was reported on 9th October 2023 by Sverker Eriksson (Ericsson). The fix was developed by Rohan McLure (IBM). General Advisory Notes ====================== URL for this Security Advisory: https://www.openssl.org/news/secadv/20240109.txt Note: the online version of the advisory may be updated with additional details over time. For details of OpenSSL severity classifications please see: https://www.openssl.org/policies/secpolicy.html -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE3HAyZir4heL0fyQ/UnRmohynnm0FAmWddmsACgkQUnRmohyn nm3nyBAAokn+TaX6ctAfk5TddGFSLabmBWOieIt52qAEqVxOnOn3IK/Ezuv6x3Gk SrXzuTY9w8mAezME2ZUrDULuixji0u/n84RRXCqJaAo0s4bPl5BY9munrG+2dBsh rusDdd8bzYdeDtRLjVeYjqMreVrpDSVx8JKto/nKcxK1w/yrzCXwpTe+n6pDu8PI OXQAcnDvFXWN7I7x23XQrv/Gx2crwNo3GuV1Seoih+595dAjjeyTsxChQCAwAooV MoCrHjdur6l9ALlQBj3Y4zZkBcyuUV4ngiNiptBVcBQB+ktcaVzMp2C6AVz3xARJ eiVXBAflL/UVkYcskgBeZfuDxS/NBcImpyKyjrfp5HQPh7ahqeyLdQraQBh82VjJ ArpKzLP/Ngl6QsCikkJZKEGAP7hTlaXShmNyKy7qIGmMNadMV4epL+lNxEEXk9aP f65obbiumGsBypY/4BzIEv2Kr9EXXeVJiHibscAaWch5e3q9e0eQuLXO/TOHpxLf NEhOXVSpBt6sp4C6hgztRTIX3/2H/xTH4ZqVwJezhra2x9ytrIDhiQVzOvE5tDdH Kzr+ydZhp7H/3NrhO2LgIHC67McU3MQNv44xUx9UTm1WaspZiZtqgP+vrgEfffs4 Vx9Uv06OxZmTD/X2OHzgNhkqN5FwHaRUhnWmRzt63XThHO1Rxm4= =8de2 -----END PGP SIGNATURE-----
