smb: client: fix use-after-free in crypt_message when using async crypto

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix use-after-free in crypt_message when using async crypto The CVE-2024-50047 fix removed asynchronous crypto handling from crypt_message(), assuming all crypto operations are synchronous. However, when hardware crypto accelerators are used, this can cause use-after-free crashes: crypt_message() // Allocate the creq buffer containing the req creq = smb2_get_aead_req(..., &req); // Async encryption returns -EINPROGRESS immediately rc = enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req); // Free creq while async operation is still in progress kvfree_sensitive(creq, ...); Hardware crypto modules often implement async AEAD operations for performance. When crypto_aead_encrypt/decrypt() returns -EINPROGRESS, the operation completes asynchronously. Without crypto_wait_req(), the function immediately frees the request buffer, leading to crashes when the driver later accesses the freed memory. This results in a use-after-free condition when the hardware crypto driver later accesses the freed request structure, leading to kernel crashes with NULL pointer dereferences. The issue occurs because crypto_alloc_aead() with mask=0 doesn't guarantee synchronous operation. Even without CRYPTO_ALG_ASYNC in the mask, async implementations can be selected. Fix by restoring the async crypto handling: • DECLARE_CRYPTO_WAIT(wait) for completion tracking • aead_request_set_callback() for async completion notification • crypto_wait_req() to wait for operation completion This ensures the request buffer isn't freed until the crypto operation completes, whether synchronous or asynchronous, while preserving the CVE-2024-50047 fix.

Timeline

1. Jul 28, 2025, 11:21 AM UTCCVE published
2. Aug 5, 2026, 12:02 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 5.10.237 · fixed in 5.10.241; From 5.15.181 · fixed in 5.15.190; From 6.1.128 · fixed in 6.1.147; From 6.6.57 · fixed in 6.6.100; From 6.11.4 · fixed in 6.12

• Linux Linux

  6.12

References 7