Bug 2054865 (CVE-2021-45402) - CVE-2021-45402 kernel: pointer leak in check_alu_op() of kernel/bpf/verifier.c
Summary: CVE-2021-45402 kernel: pointer leak in check_alu_op() of kernel/bpf/verifier.c
Keywords:
Status: NEW
Alias: CVE-2021-45402
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2055321 2055397 2055398 2055399 2055400
Blocks: 2054862
TreeView+ depends on / blocked
 
Reported: 2022-02-15 20:43 UTC by Todd Cullum
Modified: 2022-09-19 19:49 UTC (History)
48 users (show)

Fixed In Version: Linux kernel 5.16-rc6
Doc Type: If docs needed, set a value
Doc Text:
A memory leak flaw was found in the Linux kernel’s BPF subsystem in the way a user triggers the check_alu_op function of the BPF verifier. This flaw allows a local user to obtain unauthorized memory access or potentially crash the system.
Clone Of:
Environment:
Last Closed:


Attachments (Terms of Use)

Description Todd Cullum 2022-02-15 20:43:45 UTC
The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel through v5.16-rc5 did not properly update bounds while handling the mov32 instruction, which allows local users to obtain potentially sensitive address information, aka a "pointer leak."

Commits:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b1a7288dedc6caf9023f2676b4f5ed34cf0d4029
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=3cf2b61eb06765e27fec6799292d9fb46d0b7e60
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=e572ff80f05c33cd0cb4860f864f5c9c044280b6

Comment 2 Alex 2022-02-16 17:15:27 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2055321]

Comment 5 Justin M. Forbes 2022-02-17 21:57:26 UTC
This was fixed for Fedora with the 5.15.11 stable kernel updates.


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