In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: fix ntfs_mount_options leak in ntfs_fill_super()
In ntfs_fill_super(), the fc->fs_private pointer is set to NULL without
first freeing the memory it points to. This causes the subsequent call to
ntfs_fs_free() to skip freeing the ntfs_mount_options structure.
This results in a kmemleak report:
unreferenced object 0xff1100015378b800 (size 32):
comm "mount", pid 582, jiffies 4294890685
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 ed ff ed ff 00 04 00 00 ................
backtrace (crc ed541d8c):
__kmalloc_cache_noprof+0x424/0x5a0
__ntfs_init_fs_context+0x47/0x590
alloc_fs_context+0x5d8/0x960
__x64_sys_fsopen+0xb1/0x190
do_syscall_64+0x50/0x1f0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
This issue can be reproduced using the following commands:
fallocate -l 100M test.file
mount test.file /tmp/test
Since sbi->options is duplicated from fc->fs_private and does not
directly use the memory allocated for fs_private, it is unnecessary to
set fc->fs_private to NULL.
Additionally, this patch simplifies the code by utilizing the helper
function put_mount_options() instead of open-coding the cleanup logic.