ubifs: fix out-of-bounds read in signature length check

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/ubifs/auth.c"
                    ],
                    "versions": [
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "ab7405bd86331cc2dbc8201699d4adc33bea75e7",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "11abc34698cb3172badf8aa12e623f1bac98bbd8",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "8cc3da72cf57acb4b77442ea8cec48425dff7c06",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "37a9d25a563f5f9103282954ce573c4a61321e7c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "f76b79d6e42af20682495bccd22f72c7164b0018",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "a1dc246f98bb94233effa4fa3ec7bf84700bb7d1",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "83e1aa9f5f906c9b1f4949d0521f0f950a159d96",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "817aa094842dfc3a6b98c9582d4a647827f66201",
                            "lessThan": "95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/ubifs/auth.c"
                    ],
                    "versions": [
                        {
                            "version": "5.3",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.3",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.270",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.221",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.188",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.157",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.109",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.50",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.4",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }