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Bug 1844112 - GnuTLS allocates more and more memory when decrypting with AES-CCM
Summary: GnuTLS allocates more and more memory when decrypting with AES-CCM
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: gnutls
Version: 8.3
Hardware: Unspecified
OS: Unspecified
Target Milestone: rc
: 8.0
Assignee: Daiki Ueno
QA Contact: Alexander Sosedkin
Depends On:
TreeView+ depends on / blocked
Reported: 2020-06-04 16:22 UTC by Andreas Schneider
Modified: 2021-09-03 15:13 UTC (History)
5 users (show)

Fixed In Version: gnutls-3.6.14-6.el8
Doc Type: No Doc Update
Doc Text:
If this bug requires documentation, please select an appropriate Doc Type value.
Clone Of:
Last Closed: 2020-11-04 01:55:24 UTC
Type: Bug
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Gitlab gnutls gnutls merge_requests 1278 0 None None None 2020-08-24 11:29:58 UTC
Red Hat Product Errata RHBA-2020:4526 0 None None None 2020-11-04 01:55:52 UTC
Samba Project 14399 0 None None None 2020-06-04 16:22:46 UTC

Description Andreas Schneider 2020-06-04 16:22:46 UTC
Description of problem:

When you copy a 5GB file to a Samba File Server using an encrypted SMB3 connection with AES-CCM, the used memory grows up to the file size. If you transfer a 5GB file it will use 5GB of RAM.

It doesn't happen with AES-GCM!

Samba creates a cipher handle and attches it to the SMB session to avoid reallocation during a file transfer. The memory is freed once the file is transferred.

For decryption we normally call gnutls_aead_cipher_decryptv2() which grows the memory to the file size using AES-CCM. It doesn't happen with gnutls_aead_cipher_decrypt().

Comment 1 Andreas Schneider 2020-06-04 16:27:04 UTC
Note that gnutls_aead_cipher_decryptv2() will be used in RHEL 8.3 with Samba 4.12. RHEL 8.2 used gnutls_aead_cipher_decrypt().

Comment 2 Andreas Schneider 2020-06-05 13:39:42 UTC
Someone created a MR for GnuTLS to address the issue, see https://gitlab.com/gnutls/gnutls/-/merge_requests/1277

Comment 3 Andreas Schneider 2020-08-24 11:15:06 UTC
Ping. When do we get a fix for RHEL 8.3?

Comment 11 Simo Sorce 2020-08-24 16:33:03 UTC
Trying to add back the exception flag Mark, gave with the needed ITR/ITM fields

Comment 18 errata-xmlrpc 2020-11-04 01:55:24 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (gnutls bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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