Bug 1227956 (CVE-2022-48801)

Summary: VUL-0: CVE-2022-48801: kernel: iio: buffer: fix file related error handling in IIO_BUFFER_GET_FD_IOCTL
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Security Team bot <security-team>
Status: RESOLVED FIXED QA Contact: Security Team bot <security-team>
Severity: Major    
Priority: P2 - High CC: camila.matos, meissner, miroslav.franc
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/414181/
Whiteboard: CVSSv3.1:SUSE:CVE-2022-48801:7.8:(AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---
Bug Depends on:    
Bug Blocks: 1228023    

Description SMASH SMASH 2024-07-16 14:50:44 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iio: buffer: Fix file related error handling in IIO_BUFFER_GET_FD_IOCTL

If we fail to copy the just created file descriptor to userland, we
try to clean up by putting back 'fd' and freeing 'ib'. The code uses
put_unused_fd() for the former which is wrong, as the file descriptor
was already published by fd_install() which gets called internally by
anon_inode_getfd().

This makes the error handling code leaving a half cleaned up file
descriptor table around and a partially destructed 'file' object,
allowing userland to play use-after-free tricks on us, by abusing
the still usable fd and making the code operate on a dangling
'file->private_data' pointer.

Instead of leaving the kernel in a partially corrupted state, don't
attempt to explicitly clean up and leave this to the process exit
path that'll release any still valid fds, including the one created
by the previous call to anon_inode_getfd(). Simply return -EFAULT to
indicate the error.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2022-48801
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2022/CVE-2022-48801.mbox
https://git.kernel.org/stable/c/b7f54894aa7517d2b6c797a499b9f491e9db9083
https://git.kernel.org/stable/c/202071d2518537866d291aa7cf26af54e674f4d4
https://git.kernel.org/stable/c/c72ea20503610a4a7ba26c769357d31602769c01
https://www.cve.org/CVERecord?id=CVE-2022-48801