CVE-2024-26800

In the Linux kernel, the following vulnerability has been resolved:

tls: fix use-after-free on failed backlog decryption

When the decrypt request goes to the backlog and crypto_aead_decrypt returns -EBUSY, tls_do_decryption will wait until all async decryptions have completed. If one of them fails, tls_do_decryption will return -EBADMSG and tls_decrypt_sg jumps to the error path, releasing all the pages. But the pages have been passed to the async callback, and have already been released by tls_decrypt_done.

The only true async case is when crypto_aead_decrypt returns -EINPROGRESS. With -EBUSY, we already waited so we can tell tls_sw_recvmsg that the data is available for immediate copy, but we need to notify tls_decrypt_sg (via the new ->async_done flag) that the memory has already been released.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/13114dc5543069f7b97991e3b79937b6da05f5b0
• https://git.kernel.org/stable/c/1ac9fb84bc7ecd4bc6428118301d9d864d2a58d1
• https://git.kernel.org/stable/c/81be85353b0f5a7b660635634b655329b429eefe
• https://git.kernel.org/stable/c/f2b85a4cc763841843de693bbd7308fe9a2c4c89
• https://git.kernel.org/stable/c/13114dc5543069f7b97991e3b79937b6da05f5b0
• https://git.kernel.org/stable/c/1ac9fb84bc7ecd4bc6428118301d9d864d2a58d1
• https://git.kernel.org/stable/c/81be85353b0f5a7b660635634b655329b429eefe
• https://git.kernel.org/stable/c/f2b85a4cc763841843de693bbd7308fe9a2c4c89