CVE-2024-43859 f2fs: fix to truncate preallocated blocks in f2fs_file_open()

2024-08-1709:24:28

Linux

www.cve.org

linux kernel

vulnerability resolved

f2fs

preallocated blocks

file open

kernel bug

pointer dereference

null pointer

inode

mount

fscrypt_file_open

cve

EPSS

Percentile

5.0%

JSON

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

f2fs: fix to truncate preallocated blocks in f2fs_file_open()

chenyuwen reports a f2fs bug as below:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000011
fscrypt_set_bio_crypt_ctx+0x78/0x1e8
f2fs_grab_read_bio+0x78/0x208
f2fs_submit_page_read+0x44/0x154
f2fs_get_read_data_page+0x288/0x5f4
f2fs_get_lock_data_page+0x60/0x190
truncate_partial_data_page+0x108/0x4fc
f2fs_do_truncate_blocks+0x344/0x5f0
f2fs_truncate_blocks+0x6c/0x134
f2fs_truncate+0xd8/0x200
f2fs_iget+0x20c/0x5ac
do_garbage_collect+0x5d0/0xf6c
f2fs_gc+0x22c/0x6a4
f2fs_disable_checkpoint+0xc8/0x310
f2fs_fill_super+0x14bc/0x1764
mount_bdev+0x1b4/0x21c
f2fs_mount+0x20/0x30
legacy_get_tree+0x50/0xbc
vfs_get_tree+0x5c/0x1b0
do_new_mount+0x298/0x4cc
path_mount+0x33c/0x5fc
__arm64_sys_mount+0xcc/0x15c
invoke_syscall+0x60/0x150
el0_svc_common+0xb8/0xf8
do_el0_svc+0x28/0xa0
el0_svc+0x24/0x84
el0t_64_sync_handler+0x88/0xec

It is because inode.i_crypt_info is not initialized during below path:

mount
f2fs_fill_super
f2fs_disable_checkpoint
f2fs_gc
- f2fs_iget
- f2fs_truncate

So, let’s relocate truncation of preallocated blocks to f2fs_file_open(),
after fscrypt_file_open().

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/f2fs/f2fs.h",
      "fs/f2fs/file.c",
      "fs/f2fs/inode.c"
    ],
    "versions": [
      {
        "version": "d4dd19ec1ea0",
        "lessThan": "5f04969136db",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "d4dd19ec1ea0",
        "lessThan": "f44a25a8bfe0",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "d4dd19ec1ea0",
        "lessThan": "3ba0ae885215",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "d4dd19ec1ea0",
        "lessThan": "298b1e4182d6",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/f2fs/f2fs.h",
      "fs/f2fs/file.c",
      "fs/f2fs/inode.c"
    ],
    "versions": [
      {
        "version": "5.17",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.17",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.109",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.44",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10.3",
        "lessThanOrEqual": "6.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.11",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]