nvd-json-data-feeds/CVE-2024/CVE-2024-450xx/CVE-2024-45003.json

{
  "id": "CVE-2024-45003",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2024-09-04T20:15:08.823",
  "lastModified": "2024-09-04T20:15:08.823",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfs: Don't evict inode under the inode lru traversing context\n\nThe inode reclaiming process(See function prune_icache_sb) collects all\nreclaimable inodes and mark them with I_FREEING flag at first, at that\ntime, other processes will be stuck if they try getting these inodes\n(See function find_inode_fast), then the reclaiming process destroy the\ninodes by function dispose_list(). Some filesystems(eg. ext4 with\nea_inode feature, ubifs with xattr) may do inode lookup in the inode\nevicting callback function, if the inode lookup is operated under the\ninode lru traversing context, deadlock problems may happen.\n\nCase 1: In function ext4_evict_inode(), the ea inode lookup could happen\n        if ea_inode feature is enabled, the lookup process will be stuck\n\tunder the evicting context like this:\n\n 1. File A has inode i_reg and an ea inode i_ea\n 2. getfattr(A, xattr_buf) // i_ea is added into lru // lru->i_ea\n 3. Then, following three processes running like this:\n\n    PA                              PB\n echo 2 > /proc/sys/vm/drop_caches\n  shrink_slab\n   prune_dcache_sb\n   // i_reg is added into lru, lru->i_ea->i_reg\n   prune_icache_sb\n    list_lru_walk_one\n     inode_lru_isolate\n      i_ea->i_state |= I_FREEING // set inode state\n     inode_lru_isolate\n      __iget(i_reg)\n      spin_unlock(&i_reg->i_lock)\n      spin_unlock(lru_lock)\n                                     rm file A\n                                      i_reg->nlink = 0\n      iput(i_reg) // i_reg->nlink is 0, do evict\n       ext4_evict_inode\n        ext4_xattr_delete_inode\n         ext4_xattr_inode_dec_ref_all\n          ext4_xattr_inode_iget\n           ext4_iget(i_ea->i_ino)\n            iget_locked\n             find_inode_fast\n              __wait_on_freeing_inode(i_ea) ----\u2192 AA deadlock\n    dispose_list // cannot be executed by prune_icache_sb\n     wake_up_bit(&i_ea->i_state)\n\nCase 2: In deleted inode writing function ubifs_jnl_write_inode(), file\n        deleting process holds BASEHD's wbuf->io_mutex while getting the\n\txattr inode, which could race with inode reclaiming process(The\n        reclaiming process could try locking BASEHD's wbuf->io_mutex in\n\tinode evicting function), then an ABBA deadlock problem would\n\thappen as following:\n\n 1. File A has inode ia and a xattr(with inode ixa), regular file B has\n    inode ib and a xattr.\n 2. getfattr(A, xattr_buf) // ixa is added into lru // lru->ixa\n 3. Then, following three processes running like this:\n\n        PA                PB                        PC\n                echo 2 > /proc/sys/vm/drop_caches\n                 shrink_slab\n                  prune_dcache_sb\n                  // ib and ia are added into lru, lru->ixa->ib->ia\n                  prune_icache_sb\n                   list_lru_walk_one\n                    inode_lru_isolate\n                     ixa->i_state |= I_FREEING // set inode state\n                    inode_lru_isolate\n                     __iget(ib)\n                     spin_unlock(&ib->i_lock)\n                     spin_unlock(lru_lock)\n                                                   rm file B\n                                                    ib->nlink = 0\n rm file A\n  iput(ia)\n   ubifs_evict_inode(ia)\n    ubifs_jnl_delete_inode(ia)\n     ubifs_jnl_write_inode(ia)\n      make_reservation(BASEHD) // Lock wbuf->io_mutex\n      ubifs_iget(ixa->i_ino)\n       iget_locked\n        find_inode_fast\n         __wait_on_freeing_inode(ixa)\n          |          iput(ib) // ib->nlink is 0, do evict\n          |           ubifs_evict_inode\n          |            ubifs_jnl_delete_inode(ib)\n          \u2193             ubifs_jnl_write_inode\n     ABBA deadlock \u2190-----make_reservation(BASEHD)\n                   dispose_list // cannot be executed by prune_icache_sb\n                    wake_up_bit(&ixa->i_state)\n\nFix the possible deadlock by using new inode state flag I_LRU_ISOLATING\nto pin the inode in memory while inode_lr
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/03880af02a78bc9a98b5a581f529cf709c88a9b8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2a0629834cd82f05d424bbc193374f9a43d1f87d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3525ad25240dfdd8c78f3470911ed10aa727aa72",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/437741eba63bf4e437e2beb5583f8633556a2b98",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9063ab49c11e9518a3f2352434bb276cc8134c5f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b9bda5f6012dd00372f3a06a82ed8971a4c57c32",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cda54ec82c0f9d05393242b20b13f69b083f7e88",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}