Bug 1939664 (CVE-2021-3446) - CVE-2021-3446 libtpms: return of wrong initialization vector when certain symmetric ciphers are used
Summary: CVE-2021-3446 libtpms: return of wrong initialization vector when certain sym...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-3446
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: 1939665 1942902 1942903 1942904
Blocks: 1934217 1939659
TreeView+ depends on / blocked
 
Reported: 2021-03-16 19:05 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-10-29 09:59 UTC (History)
3 users (show)

Fixed In Version: libtpms 0.7.7, libtpms 0.8.2
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Doc Text:
A flaw was found in libtpms. The commonly used integration of libtpms with OpenSSL contained a vulnerability related to the returned IV (initialization vector) when certain symmetric ciphers were used. Instead of returning the last IV it returned the initial IV to the caller, thus weakening the subsequent encryption and decryption steps. The highest threat from this vulnerability is to data confidentiality.
Clone Of:
Environment:
Last Closed: 2021-10-29 09:59:03 UTC
Embargoed:

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Description Guilherme de Almeida Suckevicz 2021-03-16 19:05:58 UTC 
The commonly used integration of libtpms with OpenSSL contained a vulnerability related to the returned IV (initialization vector) when certain symmetric ciphers were used. Instead of returning the last IV it returned the initial IV to the caller. The fix for this required the copying of the last-used IV from OpenSSL so it can be return back to the caller and used in subsequent encryption and decryption steps. The side-effect of the fix is that previously chain-encrypted data will not be decryptable anymore with the TPM 2.

Reference and upstream patch:
https://github.com/stefanberger/libtpms/commit/32c159ab53db703749a8f90430cdc7b20b00975e
Comment 1 Guilherme de Almeida Suckevicz 2021-03-16 19:06:23 UTC 
Created libtpms tracking bugs for this issue:

Affects: fedora-all [bug 1939665]
Comment 3 Mauro Matteo Cascella 2021-03-25 10:42:19 UTC 
Statement:

The versions of `libtpms` as shipped with Red Hat Enterprise Linux 8 Advanced Virtualization are affected by this issue. A future update may fix the code.
Comment 4 Mauro Matteo Cascella 2021-04-15 17:46:31 UTC 
Upstream fix:
https://github.com/stefanberger/libtpms/commit/5a2f196842d9da43c65fd4a533ff348af684939f [v0.8.2]
https://github.com/stefanberger/libtpms/commit/68aa19dac7e1b80509a915ed72c2cbc1184b42bb [v0.7.7]
Comment 5 Stefan Berger 2021-10-14 21:13:55 UTC 
This bug has been fixed a while ago. I think this bugzilla can be closed.
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