CVE-2026-74350

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

ocfs2: validate fast symlink target during inode read

ocfs2validateinode_block() already rejects several inconsistent

self-contained dinodes before they are exposed to the rest of the

filesystem.  Fast symlinks need the same treatment.

A zero-cluster symlink is treated as a fast symlink and later read through

pagegetlink() and ocfs2fastsymlinkreadfolio().  That path uses

strnlen() on the inline payload and then copies len + 1 bytes into the

folio.  If a corrupt dinode stores an i_size that does not fit the inline

area or omits the terminating NUL at i_size, that copy reads past the end

of the inode block buffer.

Reject zero-cluster symlink dinodes whose i_size exceeds the inline

fast-symlink capacity or whose inline payload is not NUL-terminated

exactly at i_size when the inode block is validated.  This keeps malformed

fast symlinks from reaching the read path.

Validation reproduced this kernel report:

KASAN use-after-free in ocfs2fastsymlinkreadfolio+0x12c/0x1f0

RIP: 0033:0x7f5c6d859aa7

Read of size 3905

Call trace:

  dumpstacklvl+0x66/0xa0 (?:?)

  print_report+0xce/0x630 (?:?)

  ocfs2fastsymlinkreadfolio+0x12c/0x1f0 (fs/ocfs2/inode.c:?)

  srsoaliasreturn_thunk+0x5/0xfbef5 (?:?)

  _virtaddr_valid+0x19f/0x330 (?:?)

  kasan_report+0xe0/0x110 (?:?)

  kasancheckrange+0x105/0x1b0 (?:?)

  _asanmemcpy+0x23/0x60 (?:?)

  filemapreadfolio+0x27/0xe0 (?:?)

  filemapreadfolio+0x35/0xe0 (?:?)

  doreadcache_folio+0x138/0x230 (?:?)

  _pageget_link+0x26/0x110 (?:?)

  pagegetlink+0x2e/0x70 (?:?)

  vfs_readlink+0x15e/0x250 (?:?)

  touch_atime+0x4d/0x370 (?:?)

  do_readlinkat+0x186/0x200 (?:?)

  douseraddr_fault+0x65a/0x890 (?:?)

  _x64sys_readlink+0x46/0x60 (?:?)

  dosyscall64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)

  entrySYSCALL64afterhwframe+0x77/0x7f (?:?)