{ "schema_version": "1.6.1", "id": "RPI-CVE-2024-39488", "modified": "2026-10-07T17:22:01Z", "upstream": [ "CVE-2024-39488" ], "published": "2024-07-10T07:14:25Z", "summary": "arm64: asm-bug: Add .align 2 to the end of __BUG_ENTRY", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: asm-bug: Add .align 2 to the end of __BUG_ENTRY\n\nWhen CONFIG_DEBUG_BUGVERBOSE=n, we fail to add necessary padding bytes\nto bug_table entries, and as a result the last entry in a bug table will\nbe ignored, potentially leading to an unexpected panic(). All prior\nentries in the table will be handled correctly.\n\nThe arm64 ABI requires that struct fields of up to 8 bytes are\nnaturally-aligned, with padding added within a struct such that struct\nare suitably aligned within arrays.\n\nWhen CONFIG_DEBUG_BUGVERPOSE=y, the layout of a bug_entry is:\n\n\tstruct bug_entry {\n\t\tsigned int bug_addr_disp;\t// 4 bytes\n\t\tsigned int file_disp;\t// 4 bytes\n\t\tunsigned short line;\t\t// 2 bytes\n\t\tunsigned short flags;\t\t// 2 bytes\n\t}\n\n... with 12 bytes total, requiring 4-byte alignment.\n\nWhen CONFIG_DEBUG_BUGVERBOSE=n, the layout of a bug_entry is:\n\n\tstruct bug_entry {\n\t\tsigned int bug_addr_disp;\t// 4 bytes\n\t\tunsigned short flags;\t\t// 2 bytes\n\t\t< implicit padding >\t\t// 2 bytes\n\t}\n\n... with 8 bytes total, with 6 bytes of data and 2 bytes of trailing\npadding, requiring 4-byte alginment.\n\nWhen we create a bug_entry in assembly, we align the start of the entry\nto 4 bytes, which implicitly handles padding for any prior entries.\nHowever, we do not align the end of the entry, and so when\nCONFIG_DEBUG_BUGVERBOSE=n, the final entry lacks the trailing padding\nbytes.\n\nFor the main kernel image this is not a problem as find_bug() doesn't\ndepend on the trailing padding bytes when searching for entries:\n\n\tfor (bug = __start___bug_table; bug < __stop___bug_table; ++bug)\n\t\tif (bugaddr == bug_addr(bug))\n\t\t\treturn bug;\n\nHowever for modules, module_bug_finalize() depends on the trailing\nbytes when calculating the number of entries:\n\n\tmod->num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);\n\n... and as the last bug_entry lacks the necessary padding bytes, this entry\nwill not be counted, e.g. in the case of a single entry:\n\n\tsechdrs[i].sh_size == 6\n\tsizeof(struct bug_entry) == 8;\n\n\tsechdrs[i].sh_size / sizeof(struct bug_entry) == 0;\n\nConsequently module_find_bug() will miss the last bug_entry when it does:\n\n\tfor (i = 0; i < mod->num_bugs; ++i, ++bug)\n\t\tif (bugaddr == bug_addr(bug))\n\t\t\tgoto out;\n\n... which can lead to a kenrel panic due to an unhandled bug.\n\nThis can be demonstrated with the following module:\n\n\tstatic int __init buginit(void)\n\t{\n\t\tWARN(1, \"hello\\n\");\n\t\treturn 0;\n\t}\n\n\tstatic void __exit bugexit(void)\n\t{\n\t}\n\n\tmodule_init(buginit);\n\tmodule_exit(bugexit);\n\tMODULE_LICENSE(\"GPL\");\n\n... which will trigger a kernel panic when loaded:\n\n\t------------[ cut here ]------------\n\thello\n\tUnexpected kernel BRK exception at EL1\n\tInternal error: BRK handler: 00000000f2000800 [#1] PREEMPT SMP\n\tModules linked in: hello(O+)\n\tCPU: 0 PID: 50 Comm: insmod Tainted: G O 6.9.1 #8\n\tHardware name: linux,dummy-virt (DT)\n\tpstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n\tpc : buginit+0x18/0x1000 [hello]\n\tlr : buginit+0x18/0x1000 [hello]\n\tsp : ffff800080533ae0\n\tx29: ffff800080533ae0 x28: 0000000000000000 x27: 0000000000000000\n\tx26: ffffaba8c4e70510 x25: ffff800080533c30 x24: ffffaba8c4a28a58\n\tx23: 0000000000000000 x22: 0000000000000000 x21: ffff3947c0eab3c0\n\tx20: ffffaba8c4e3f000 x19: ffffaba846464000 x18: 0000000000000006\n\tx17: 0000000000000000 x16: ffffaba8c2492834 x15: 0720072007200720\n\tx14: 0720072007200720 x13: ffffaba8c49b27c8 x12: 0000000000000312\n\tx11: 0000000000000106 x10: ffffaba8c4a0a7c8 x9 : ffffaba8c49b27c8\n\tx8 : 00000000ffffefff x7 : ffffaba8c4a0a7c8 x6 : 80000000fffff000\n\tx5 : 0000000000000107 x4 : 0000000000000000 x3 : 0000000000000000\n\tx2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff3947c0eab3c0\n\tCall trace:\n\t buginit+0x18/0x1000 [hello]\n\t do_one_initcall+0x80/0x1c8\n\t do_init_module+0x60/0x218\n\t load_module+0x1ba4/0x1d70\n\t __do_sys_init_module+0x198/0x1d0\n\t __arm64_sys_init_module+0x1c/0x28\n\t invoke_syscall+0x48/0x114\n\t el0_svc\n---truncated---", "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.21-1+rpt1", "1:6.1.47-1+rpt2", "1:6.1.47-1+rpt4", "1:6.1.54-1+rpt2", "1:6.1.58-1+rpt2", "1:6.1.63-1+rpt1", "1:6.1.73-1+rpt1", "1:6.6.20-1+rpt1", "1:6.6.28-1+rpt1", "1:6.6.31-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi1-rpi-v8", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v8", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-2712", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v8", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-2712", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v8", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-2712", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v8", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-2712", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v8", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-2712", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-v8", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.28+rpt-rpi-2712", "binary_version": "1:6.6.28-1+rpt1" }, { "binary_name": "linux-image-6.6.28+rpt-rpi-v8", "binary_version": "1:6.6.28-1+rpt1" }, { "binary_name": "linux-image-6.6.31+rpt-rpi-2712", "binary_version": "1:6.6.31-1+rpt1" }, { "binary_name": "linux-image-6.6.31+rpt-rpi-v8", "binary_version": "1:6.6.31-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.1.21-1+rpt1": { "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed", "upstream_version": "6.1.21", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.93" }, "1:6.1.47-1+rpt2": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.93" }, "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.93", "compiled_filter": false }, "1:6.1.54-1+rpt2": { "linux_commit": "2906f7abdc03d4a92b6b0e2e0c87ea2a9dffe8f7", "upstream_version": "6.1.54", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.93" }, "1:6.1.58-1+rpt2": { "linux_commit": "ccf1586ad0663fa91238ac56abf6340d6d740d18", 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"references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2024-39488" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f221bd58db0f6ca087ac0392284f6bce21f4f8ea" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/22469a0335a1a1a690349b58bcb55822457df81e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/461a760d578b2b2c2faac3040b6b7c77baf128f8" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c1929c041a262a4a27265db8dce3619c92aa678c" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/3fd487ffaa697ddb05af78a75aaaddabe71c52b0" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9f2ad88f9b349554f64e4037ec185c84d7dd9c7d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c27a2f7668e215c1ebbccd96fab27a220a93f1f7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ffbf4fb9b5c12ff878a10ea17997147ea4ebea6f" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-05-12T04:54:46Z" } }