{"id":"CVE-2023-54137","state":"PUBLISHED","title":"vfio/type1: fix cap_migration information leak","description":"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 << __ffs(iommu->pgsize_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->id, cap->version);\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.","publishedAt":"2025-12-24T13:06:52.689Z","updatedAt":"2026-05-11T19:56:12.086Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"ad83d83dd891244de0d07678b257dc976db7c132","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"13fd667db999bffb557c5de7adb3c14f1713dd51","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"f6f300ecc196d243c02adeb9ee0c62c677c24bfb","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"cbac29a1caa49a34e131394e1f4d924a76d8b0c9","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"1b5feb8497cdb5b9962db2700814bffbc030fb4a","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"cd24e2a60af633f157d7e59c0a6dba64f131c0b1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/vfio_iommu_type1.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.8","versionType":"semver"},{"version":"5.10.195","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.132","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.53","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.16","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5.3","status":"unaffected","lessThanOrEqual":"6.5.*","versionType":"semver"},{"version":"6.6","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/vfio_iommu_type1.c"]}],"references":["https://git.kernel.org/stable/c/ad83d83dd891244de0d07678b257dc976db7c132","https://git.kernel.org/stable/c/13fd667db999bffb557c5de7adb3c14f1713dd51","https://git.kernel.org/stable/c/f6f300ecc196d243c02adeb9ee0c62c677c24bfb","https://git.kernel.org/stable/c/cbac29a1caa49a34e131394e1f4d924a76d8b0c9","https://git.kernel.org/stable/c/1b5feb8497cdb5b9962db2700814bffbc030fb4a","https://git.kernel.org/stable/c/cd24e2a60af633f157d7e59c0a6dba64f131c0b1"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:42.242Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/54xxx/CVE-2023-54137.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-54137","state":"PUBLISHED","datePublished":"2025-12-24T13:06:52.689Z","dateUpdated":"2026-05-11T19:56:12.086Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-24T13:02:52.522Z"},"containers":{"cna":{"title":"vfio/type1: fix cap_migration information leak","descriptions":[{"lang":"en","value":"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 << __ffs(iommu->pgsize_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->id, cap->version);\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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"ad83d83dd891244de0d07678b257dc976db7c132","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"13fd667db999bffb557c5de7adb3c14f1713dd51","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"f6f300ecc196d243c02adeb9ee0c62c677c24bfb","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"cbac29a1caa49a34e131394e1f4d924a76d8b0c9","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"1b5feb8497cdb5b9962db2700814bffbc030fb4a","versionType":"git"},{"version":"ad721705d09c62f0d108a6b4f59867ebfd592c90","status":"affected","lessThan":"cd24e2a60af633f157d7e59c0a6dba64f131c0b1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/vfio_iommu_type1.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.8","versionType":"semver"},{"version":"5.10.195","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.132","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.53","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.16","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5.3","status":"unaffected","lessThanOrEqual":"6.5.*","versionType":"semver"},{"version":"6.6","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/vfio_iommu_type1.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ad83d83dd891244de0d07678b257dc976db7c132"},{"url":"https://git.kernel.org/stable/c/13fd667db999bffb557c5de7adb3c14f1713dd51"},{"url":"https://git.kernel.org/stable/c/f6f300ecc196d243c02adeb9ee0c62c677c24bfb"},{"url":"https://git.kernel.org/stable/c/cbac29a1caa49a34e131394e1f4d924a76d8b0c9"},{"url":"https://git.kernel.org/stable/c/1b5feb8497cdb5b9962db2700814bffbc030fb4a"},{"url":"https://git.kernel.org/stable/c/cd24e2a60af633f157d7e59c0a6dba64f131c0b1"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T19:56:12.086Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"5.10.195"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"5.15.132"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"6.1.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"6.4.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"6.5.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"6.6"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}