{"id":"CVE-2023-54137","summary":"vfio/type1: fix cap_migration information leak","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/type1: fix cap_migration information leak\n\nFix an information leak where an uninitialized hole in struct\nvfio_iommu_type1_info_cap_migration on the stack is exposed to userspace.\n\nThe definition of struct vfio_iommu_type1_info_cap_migration contains a hole as\nshown in this pahole(1) output:\n\n  struct vfio_iommu_type1_info_cap_migration {\n          struct vfio_info_cap_header header;              /*     0     8 */\n          __u32                      flags;                /*     8     4 */\n\n          /* XXX 4 bytes hole, try to pack */\n\n          __u64                      pgsize_bitmap;        /*    16     8 */\n          __u64                      max_dirty_bitmap_size; /*    24     8 */\n\n          /* size: 32, cachelines: 1, members: 4 */\n          /* sum members: 28, holes: 1, sum holes: 4 */\n          /* last cacheline: 32 bytes */\n  };\n\nThe cap_mig variable is filled in without initializing the hole:\n\n  static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,\n                         struct vfio_info_cap *caps)\n  {\n      struct vfio_iommu_type1_info_cap_migration cap_mig;\n\n      cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;\n      cap_mig.header.version = 1;\n\n      cap_mig.flags = 0;\n      /* support minimum pgsize */\n      cap_mig.pgsize_bitmap = (size_t)1 \u003c\u003c __ffs(iommu-\u003epgsize_bitmap);\n      cap_mig.max_dirty_bitmap_size = DIRTY_BITMAP_SIZE_MAX;\n\n      return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));\n  }\n\nThe structure is then copied to a temporary location on the heap. At this point\nit's already too late and ioctl(VFIO_IOMMU_GET_INFO) copies it to userspace\nlater:\n\n  int vfio_info_add_capability(struct vfio_info_cap *caps,\n                   struct vfio_info_cap_header *cap, size_t size)\n  {\n      struct vfio_info_cap_header *header;\n\n      header = vfio_info_cap_add(caps, size, cap-\u003eid, cap-\u003eversion);\n      if (IS_ERR(header))\n          return PTR_ERR(header);\n\n      memcpy(header + 1, cap + 1, size - sizeof(*header));\n\n      return 0;\n  }\n\nThis issue was found by code inspection.","modified":"2026-03-31T17:29:37.594746Z","published":"2025-12-24T13:06:52.689Z","related":["SUSE-SU-2026:0278-1","SUSE-SU-2026:0281-1","SUSE-SU-2026:0293-1","SUSE-SU-2026:0315-1","SUSE-SU-2026:20477-1","SUSE-SU-2026:20498-1","SUSE-SU-2026:20845-1","SUSE-SU-2026:20876-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/54xxx/CVE-2023-54137.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/13fd667db999bffb557c5de7adb3c14f1713dd51"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1b5feb8497cdb5b9962db2700814bffbc030fb4a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ad83d83dd891244de0d07678b257dc976db7c132"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cbac29a1caa49a34e131394e1f4d924a76d8b0c9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cd24e2a60af633f157d7e59c0a6dba64f131c0b1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f6f300ecc196d243c02adeb9ee0c62c677c24bfb"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/54xxx/CVE-2023-54137.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-54137"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ad721705d09c62f0d108a6b4f59867ebfd592c90"},{"fixed":"ad83d83dd891244de0d07678b257dc976db7c132"},{"fixed":"13fd667db999bffb557c5de7adb3c14f1713dd51"},{"fixed":"f6f300ecc196d243c02adeb9ee0c62c677c24bfb"},{"fixed":"cbac29a1caa49a34e131394e1f4d924a76d8b0c9"},{"fixed":"1b5feb8497cdb5b9962db2700814bffbc030fb4a"},{"fixed":"cd24e2a60af633f157d7e59c0a6dba64f131c0b1"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-54137.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.8.0"},{"fixed":"5.10.195"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.132"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.4.16"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.5.0"},{"fixed":"6.5.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-54137.json"}}],"schema_version":"1.7.5"}