{"id":"AZL-100355","summary":"CVE-2026-89557 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd: do overflow check for sb-\u003ebblog_shift in super_1_load()\n\nIn super_1_load(), sb-\u003ebblog_shift is an __u8 type value loaded from on-\ndisk superblock. It is used for badblocks API badblocks_set() by the\nfollowing sequence,\n\n 1930   rdev-\u003ebadblocks.shift = sb-\u003ebblog_shift;\n 1931   for (i = 0 ; i \u003c (sectors \u003c\u003c (9-3)) ; i++, bbp++) {\n 1932           u64 bb = le64_to_cpu(*bbp);\n 1933           int count = bb & (0x3ff);\n 1934           u64 sector = bb \u003e\u003e 10;\n 1935           sector \u003c\u003c= sb-\u003ebblog_shift;\n 1936           count \u003c\u003c= sb-\u003ebblog_shift;\n 1937           if (bb + 1 == 0)\n 1938                   break;\n 1939           if (!badblocks_set(&rdev-\u003ebadblocks, sector, count, 1))\n 1940                   return -EINVAL;\n 1941   }\n\nbb-\u003ebblog_shit is in range of 0-255, variable sector is 64bit width, for\nan invalid bb-\u003ebblog_shit, it is possible to make sector be overflowed\nby the following calculation,\n 1935           sector \u003c\u003c= sb-\u003ebblog_shift;\nThen in turn when call badblocks_set() at line 1939 with the invalid\nrdev-\u003ebadblocks.shift set at line 1930, may result an overflow inside\n_badblocks_clear() in block/badblocks.c.\n\nAlthough there are many places to call badblocks APIs, the non-zero\nshift value is only used in super_1_load(), other places always use 0 as\nthe shift value. Therefore it is unnecessary to do a general shift value\noverflow check inside badblock API, and just check here as the caller.\n\nThis may avoid unnecessary check, make the badblocks API code more simple\nand elegant.","modified":"2026-09-13T06:06:36Z","published":"2026-09-11T20:19:39Z","upstream":["CVE-2026-89557"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89557"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100355.json"}}],"schema_version":"1.9.0"}