Linux AF_ALG Crypto Code Removing Zero-Copy Support Out Of Security Concerns
The Linux kernel is removing zero-copy support from its AF_ALG cryptographic subsystem due to security concerns. This change aims to reduce the risk of vulnerabilities associated with direct memory access by user-space applications. While it may slightly decrease performance, the update prioritizes safety without breaking the existing user API.
- ▪The removal of zero-copy support is a proactive measure in response to recent security issues in the Linux kernel.
- ▪Zero-copy functionality has been deemed risky as it can lead to potential exploits by allowing user-space modifications of memory during cryptographic operations.
- ▪The change will be included in the upcoming Linux 7.2 merge window, with the kernel making stable internal copies of data for cryptographic operations.
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Linux AF_ALG Crypto Code Removing Zero-Copy Support Out Of Security Concerns Written by Michael Larabel in Linux Security on 18 May 2026 at 08:00 AM EDT. Add A Comment Given all the recent Linux kernel security concerns and new bugs being discovered, the Linux cryptographic subsystem is proactively dropping zero-copy functionality from AF_ALG due to growing security concerns. Zero-copy support is great for better performance and efficiency, but in kernel space it does increase the likelihood of exploiting its semantics by malicious software. The Linux AF_ALF code for exposing the Linux kernel's cryptographic API to user-space will be removing zero-copy support from the SKCIPHER and AEAD code to reduce security risks.
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