Impact
s2n-tls uses the Linux atexit function to register functions that clean up the global state when the process exits. In multi-threaded environments, the atexit handler may clean up state which is still in use by other threads. When this occurs, the exiting process may experience a segmentation fault or other undefined behavior.
Customers of AWS services do not need to take action. Applications using s2n-tls should upgrade to the most recent release of s2n-tls.
Impacted versions: < v1.5.9.
Patches
The patch commit 493b771 is included in s2n-tls v1.5.9 [1]
Workarounds
The atexit handler may be disabled by calling s2n_disable_atexit() prior to initializing s2n-tls. The atexit handler is off by default in the patched versions. For further details, refer to s2n-tls Usage Guide: Initialization and Teardown.
If you have any questions or comments about this advisory, we ask that you contact AWS/Amazon Security via our vulnerability reporting page [2] or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
[1] https://github.com/aws/s2n-tls/releases/tag/v1.5.9
[2] Vulnerability reporting page: https://aws.amazon.com/security/vulnerability-reporting
References
Impact
s2n-tls uses the Linux atexit function to register functions that clean up the global state when the process exits. In multi-threaded environments, the atexit handler may clean up state which is still in use by other threads. When this occurs, the exiting process may experience a segmentation fault or other undefined behavior.
Customers of AWS services do not need to take action. Applications using s2n-tls should upgrade to the most recent release of s2n-tls.
Impacted versions: < v1.5.9.
Patches
The patch commit 493b771 is included in s2n-tls v1.5.9 [1]
Workarounds
The atexit handler may be disabled by calling
s2n_disable_atexit()prior to initializing s2n-tls. The atexit handler is off by default in the patched versions. For further details, refer to s2n-tls Usage Guide: Initialization and Teardown.If you have any questions or comments about this advisory, we ask that you contact AWS/Amazon Security via our vulnerability reporting page [2] or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
[1] https://github.com/aws/s2n-tls/releases/tag/v1.5.9
[2] Vulnerability reporting page: https://aws.amazon.com/security/vulnerability-reporting
References