Withdrawn by the publisher.

In the Linux kernel, the following vulnerability has been resolved:

ntfs: fail attrlist updates when the superblock is inactive

generic_shutdown_super() clears SB_ACTIVE before evicting cached inodes. If eviction selects the fake inode for a base inode's unnamed $ATTRIBUTE_LIST attribute, ntfs_evict_big_inode() drops the fake inode's reference on the base inode while the fake inode is still hashed and marked I_FREEING.

That iput can synchronously write back the base inode. The writeback path may update mapping pairs and call ntfs_attrlist_update(), which unconditionally calls ntfs_attr_iget() for the same $ATTRIBUTE_LIST fake inode. VFS then finds the I_FREEING inode and waits for eviction to finish, but the current task is still inside that eviction path, causing a self-deadlock in find_inode().

Fix this by mirroring the teardown guard used by __ntfs_write_inode(): once SB_ACTIVE has been cleared, do not try to iget the attribute-list fake inode. Return -EIO so teardown aborts the update instead of waiting on the inode it is evicting.

In the Linux kernel, the following vulnerability has been resolved:

ntfs: fail attrlist updates when the superblock is inactive

generic_shutdown_super() clears SB_ACTIVE before evicting cached inodes. If eviction selects the fake inode for a base inode's unnamed $ATTRIBUTE_LIST attribute, ntfs_evict_big_inode() drops the fake inode's reference on the base inode while the fake inode is still hashed and marked I_FREEING.

That iput can synchronously write back the base inode. The writeback path may update mapping pairs and call ntfs_attrlist_update(), which unconditionally calls ntfs_attr_iget() for the same $ATTRIBUTE_LIST fake inode. VFS then finds the I_FREEING inode and waits for eviction to finish, but the current task is still inside that eviction path, causing a self-deadlock in find_inode().

Fix this by mirroring the teardown guard used by __ntfs_write_inode(): once SB_ACTIVE has been cleared, do not try to iget the attribute-list fake inode. Return -EIO so teardown aborts the update instead of waiting on the inode it is evicting.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 93 more

In the Linux kernel, the following vulnerability has been resolved: ntfs: fail attrlist updates when the superblock is inactive generic_shutdown_super() clears SB_ACTIVE before evicting cached inodes. If eviction selects the fake inode for a base inode's unnamed $ATTRIBUTE_LIST attribute, ntfs_evict_big_inode() drops the fake inode's reference on the base inode while the fake inode is still hashed and marked I_FREEING. That iput can synchronously write back the base inode. The writeback path may update mapping pairs and call ntfs_attrlist_update(), which unconditionally calls ntfs_attr_iget() for the same $ATTRIBUTE_LIST fake inode. VFS then finds the I_FREEING inode and waits for eviction to finish, but the current task is still inside that eviction path, causing a self-deadlock in find_inode(). Fix this by mirroring the teardown guard used by __ntfs_write_inode(): once SB_ACTIVE has been cleared, do not try to iget the attribute-list fake inode. Return -EIO so teardown aborts the update instead of waiting on the inode it is evicting.

Ein Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um root Rechte zu erlangen, um einen Denial of Service herbeizuführen oder einen nicht näher spezifizierten Angriff durchzuführen.