Bug 1220844 (CVE-2021-47081)

Summary: VUL-0: CVE-2021-47081: kernel: habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Kernel Bugs <kernel-bugs>
Status: RESOLVED FIXED QA Contact: Security Team bot <security-team>
Severity: Normal    
Priority: P5 - None CC: rfrohl
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/396019/
Whiteboard:
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description SMASH SMASH 2024-03-04 10:24:50 UTC 
In the Linux kernel, the following vulnerability has been resolved:

habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory

Our code analyzer reported a uaf.

In gaudi_memset_device_memory, cb is get via hl_cb_kernel_create()
with 2 refcount.
If hl_cs_allocate_job() failed, the execution runs into release_cb
branch. One ref of cb is dropped by hl_cb_put(cb) and could be freed
if other thread also drops one ref. Then cb is used by cb->id later,
which is a potential uaf.

My patch add a variable 'id' to accept the value of cb->id before the
hl_cb_put(cb) is called, to avoid the potential uaf.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47081
https://www.cve.org/CVERecord?id=CVE-2021-47081
https://git.kernel.org/stable/c/115726c5d312b462c9d9931ea42becdfa838a076
https://git.kernel.org/stable/c/b49f5af30b0e4064fbd91e83823a4bfcb2c7a3e7
https://bugzilla.redhat.com/show_bug.cgi?id=2267535
Comment 1 Robert Frohl 2024-03-04 10:26:26 UTC 
does not affect SUSE kernels, closing