UBUNTU-CVE-2021-46974

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    UBUNTU-CVE-2021-46974

    Published: 27 Feb 2024Last Modified: 9 Sept 2026
    Upstream:
    CVE-2021-46974

    Summary:

    Details: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix masking negation logic upon negative dst register The negation logic for the case where the off_reg is sitting in the dst register is not correct given then we cannot just invert the add to a sub or vice versa. As a fix, perform the final bitwise and-op unconditionally into AX from the off_reg, then move the pointer from the src to dst and finally use AX as the source for the original pointer arithmetic operation such that the inversion yields a correct result. The single non-AX mov in between is possible given constant blinding is retaining it as it's not an immediate based operation.

    References: https://ubuntu.com/security/CVE-2021-46974, https://git.kernel.org/linus/b9b34ddbe2076ade359cd5ce7537d5ed019e9807, https://git.kernel.org/stable/c/4d542ddb88fb2f39bf7f14caa2902f3e8d06f6ba, https://git.kernel.org/stable/c/0e2dfdc74a7f4036127356d42ea59388f153f42c, https://git.kernel.org/stable/c/53e0db429b37a32b8fc706d0d90eb4583ad13848, https://git.kernel.org/stable/c/2cfa537674cd1051a3b8111536d77d0558f33d5d, https://git.kernel.org/stable/c/6eba92a4d4be8feb4dc33976abac544fa99d6ecc, https://git.kernel.org/stable/c/7cf64d8679ca1cb20cf57d6a88bfee79a0922a66, https://git.kernel.org/stable/c/b9b34ddbe2076ade359cd5ce7537d5ed019e9807, https://www.cve.org/CVERecord?id=CVE-2021-46974

    Affected packages

    Package

    Name: linux-azure

    Purl: pkg:deb/ubuntu/linux-azure?arch=source&distro=trusty%2Fesm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -4.15.0-1118.131~14.04.1

    Affected versions

    4.15.0-1023.24~14.04.1
    4.15.0-1030.31~14.04.1
    4.15.0-1031.32~14.04.1
    4.15.0-1032.33~14.04.2
    4.15.0-1035.36~14.04.2
    4.15.0-1036.38~14.04.2
    4.15.0-1037.39~14.04.2
    4.15.0-1039.41~14.04.2
    4.15.0-1040.44~14.04.1
    4.15.0-1041.45~14.04.1
    4.15.0-1042.46~14.04.1
    4.15.0-1045.49~14.04.1
    4.15.0-1046.50~14.04.1
    4.15.0-1047.51~14.04.1
    4.15.0-1049.54~14.04.1
    4.15.0-1050.55~14.04.1
    4.15.0-1051.56~14.04.1
    4.15.0-1052.57~14.04.1
    4.15.0-1055.60~14.04.1
    4.15.0-1056.61~14.04.1
    4.15.0-1057.62~14.04.1
    4.15.0-1059.64~14.04.1
    4.15.0-1060.65~14.04.1
    4.15.0-1061.66~14.04.1
    4.15.0-1063.68~14.04.1
    4.15.0-1064.69~14.04.1
    4.15.0-1066.71~14.04.1
    4.15.0-1067.72~14.04.1
    4.15.0-1069.74~14.04.1
    4.15.0-1071.76~14.04.1
    4.15.0-1074.79~14.04.1
    4.15.0-1077.82~14.04.1
    4.15.0-1082.92~14.04.1
    4.15.0-1083.93~14.04.1
    4.15.0-1089.99~14.04.1
    4.15.0-1091.101~14.04.1
    4.15.0-1092.102~14.04.1
    4.15.0-1093.103~14.04.1
    4.15.0-1095.105~14.04.1
    4.15.0-1096.106~14.04.1
    4.15.0-1098.109~14.04.1
    4.15.0-1100.111~14.04.1
    4.15.0-1102.113~14.04.1
    4.15.0-1103.114~14.04.1
    4.15.0-1106.118~14.04.1
    4.15.0-1108.120~14.04.1
    4.15.0-1109.121~14.04.1
    4.15.0-1110.122~14.04.1
    4.15.0-1111.123~14.04.1
    4.15.0-1112.124~14.04.1
    4.15.0-1113.126~14.04.1
    4.15.0-1114.127~14.04.1
    4.15.0-1115.128~14.04.1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2021-46974 | CVE-DB