CVE-2022-50342

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

floppy: Fix memory leak in do_floppy_init()

A memory leak was reported when floppy_alloc_disk() failed in
do_floppy_init().

unreferenced object 0xffff888115ed25a0 (size 8):
comm “modprobe”, pid 727, jiffies 4295051278 (age 25.529s)
hex dump (first 8 bytes):
00 ac 67 5b 81 88 ff ff ..g[….
backtrace:
[] __kmalloc_node+0x4c/0xc0
[] blk_mq_realloc_tag_set_tags.part.0+0x6f/0x180
[] blk_mq_alloc_tag_set+0x573/0x1130
[] 0xffffffffc06b8b08
[] do_one_initcall+0xd0/0x4f0
[] do_init_module+0x1a4/0x680
[] load_module+0x6249/0x7110
[] __do_sys_finit_module+0x140/0x200
[] do_syscall_64+0x35/0x80
[] entry_SYSCALL_64_after_hwframe+0x46/0xb0
unreferenced object 0xffff88810fc30540 (size 32):
comm “modprobe”, pid 727, jiffies 4295051278 (age 25.529s)
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 00 00 00 00 00 00 00 00 …………….
backtrace:
[] __kmalloc_node+0x4c/0xc0
[] blk_mq_alloc_tag_set+0x393/0x1130
[] 0xffffffffc06b8b08
[] do_one_initcall+0xd0/0x4f0
[] do_init_module+0x1a4/0x680
[] load_module+0x6249/0x7110
[] __do_sys_finit_module+0x140/0x200
[] do_syscall_64+0x35/0x80
[] entry_SYSCALL_64_after_hwframe+0x46/0xb0

If the floppy_alloc_disk() failed, disks of current drive will not be set,
thus the lastest allocated set->tag cannot be freed in the error handling
path. A simple call graph shown as below:

floppy_module_init()
floppy_init()
do_floppy_init()
for (drive = 0; drive tag allocated
floppy_alloc_disk()
blk_mq_alloc_disk() # error occurred, disks failed to allocated

->out_put_disk:
for (drive = 0; drive tag leaked

Fix this problem by free the set->tag of current drive before jump to
error handling path.

[efremov: added stable list, changed title]