Vulnerability CVE-2022-48635

Vulnerability CVE-2022-48635

Published: 2024-04-28

Description:

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

fsdax: Fix infinite loop in dax_iomap_rw()

I got an infinite loop and a WARNING report when executing a tail command
in virtiofs.

WARNING: CPU: 10 PID: 964 at fs/iomap/iter.c:34 iomap_iter+0x3a2/0x3d0
Modules linked in:
CPU: 10 PID: 964 Comm: tail Not tainted 5.19.0-rc7
Call Trace:
<TASK>
dax_iomap_rw+0xea/0x620
? __this_cpu_preempt_check+0x13/0x20
fuse_dax_read_iter+0x47/0x80
fuse_file_read_iter+0xae/0xd0
new_sync_read+0xfe/0x180
? 0xffffffff81000000
vfs_read+0x14d/0x1a0
ksys_read+0x6d/0xf0
__x64_sys_read+0x1a/0x20
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The tail command will call read() with a count of 0. In this case,
iomap_iter() will report this WARNING, and always return 1 which casuing
the infinite loop in dax_iomap_rw().

Fixing by checking count whether is 0 in dax_iomap_rw().

References:

https://git.kernel.org/stable/c/929ef155e1da41c06f4d8ca86ae12b851a83a744

https://git.kernel.org/stable/c/60644dffac87b1bb47bdb393aa29d5f2ffcf41a0

https://git.kernel.org/stable/c/17d9c15c9b9e7fb285f7ac5367dfb5f00ff575e3

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