Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
blk-crypto: make blk_crypto_evict_key() more robust
If blk_crypto_evict_key() sees that the key is still in-use (due to a bug) or that ->keyslot_evict failed, it currently just returns while leaving the key linked into the keyslot management structures.
However, blk_crypto_evict_key() is only called in contexts such as inode eviction where failure is not an option. So actually the caller proceeds with freeing the blk_crypto_key regardless of the return value of blk_crypto_evict_key().
These two assumptions don’t match, and the result is that there can be a use-after-free in blk_crypto_reprogram_all_keys() after one of these errors occurs. (Note, these errors shouldn’t happen; we’re just talking about what happens if they do anyway.)
Fix this by making blk_crypto_evict_key() unlink the key from the keyslot management structures even on failure.
Also improve some comments.
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 5.14.0 (+1 more)
In the Linux kernel, the following vulnerability has been resolved:
blk-crypto: make blk_crypto_evict_key() more robust
If blk_crypto_evict_key() sees that the key is still in-use (due to a bug) or that ->keyslot_evict failed, it currently just returns while leaving the key linked into the keyslot management structures.
However, blk_crypto_evict_key() is only called in contexts such as inode eviction where failure is not an option. So actually the caller proceeds with freeing the blk_crypto_key regardless of the return value of blk_crypto_evict_key().
These two assumptions don’t match, and the result is that there can be a use-after-free in blk_crypto_reprogram_all_keys() after one of these errors occurs. (Note, these errors shouldn’t happen; we’re just talking about what happens if they do anyway.)
Fix this by making blk_crypto_evict_key() unlink the key from the keyslot management structures even on failure.
Also improve some comments.