// For flags

CVE-2024-38626

fuse: clear FR_SENT when re-adding requests into pending list

Severity Score

"-"
*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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

fuse: clear FR_SENT when re-adding requests into pending list

The following warning was reported by lee bruce:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 8264 at fs/fuse/dev.c:300
fuse_request_end+0x685/0x7e0 fs/fuse/dev.c:300
Modules linked in:
CPU: 0 PID: 8264 Comm: ab2 Not tainted 6.9.0-rc7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:fuse_request_end+0x685/0x7e0 fs/fuse/dev.c:300
......
Call Trace:
<TASK>
fuse_dev_do_read.constprop.0+0xd36/0x1dd0 fs/fuse/dev.c:1334
fuse_dev_read+0x166/0x200 fs/fuse/dev.c:1367
call_read_iter include/linux/fs.h:2104 [inline]
new_sync_read fs/read_write.c:395 [inline]
vfs_read+0x85b/0xba0 fs/read_write.c:476
ksys_read+0x12f/0x260 fs/read_write.c:619
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xce/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
......
</TASK>

The warning is due to the FUSE_NOTIFY_RESEND notify sent by the write()
syscall in the reproducer program and it happens as follows:

(1) calls fuse_dev_read() to read the INIT request
The read succeeds. During the read, bit FR_SENT will be set on the
request.
(2) calls fuse_dev_write() to send an USE_NOTIFY_RESEND notify
The resend notify will resend all processing requests, so the INIT
request is moved from processing list to pending list again.
(3) calls fuse_dev_read() with an invalid output address
fuse_dev_read() will try to copy the same INIT request to the output
address, but it will fail due to the invalid address, so the INIT
request is ended and triggers the warning in fuse_request_end().

Fix it by clearing FR_SENT when re-adding requests into pending list.

*Credits: N/A
CVSS Scores
Attack Vector
-
Attack Complexity
-
Privileges Required
-
User Interaction
-
Scope
-
Confidentiality
-
Integrity
-
Availability
-
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-06-18 CVE Reserved
  • 2024-06-21 CVE Published
  • 2024-06-22 EPSS Updated
  • 2024-12-19 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 6.9 < 6.9.4
Search vendor "Linux" for product "Linux Kernel" and version " >= 6.9 < 6.9.4"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 6.9 < 6.10
Search vendor "Linux" for product "Linux Kernel" and version " >= 6.9 < 6.10"
en
Affected