CVE-2023-41325OP-TEE double free in shdr_verify_signature

Official description

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.20 and prior to version 3.22, `shdr_verify_signature` can make a double free. `shdr_verify_signature` used to verify a TA binary before it is loaded. To verify a signature of it, allocate a memory for RSA key. RSA key allocate function (`sw_crypto_acipher_alloc_rsa_public_key`) will try to allocate a memory (which is optee’s heap memory). RSA key is consist of exponent and modulus (represent as variable `e`, `n`) and it allocation is not atomic way, so it may succeed in `e` but fail in `n`. In this case sw_crypto_acipher_alloc_rsa_public_key` will free on `e` and return as it is failed but variable ‘e’ is remained as already freed memory address . `shdr_verify_signature` will free again that memory (which is `e`) even it is freed when it failed allocate RSA key. A patch is available in version 3.22. No known workarounds are available.

Affected products (as reported)

References

• https://github.com/OP-TEE/optee_os/security/advisories/GHSA-jrw7-63cq-7vhm x_refsource_CONFIRM
• https://github.com/OP-TEE/optee_os/commit/e2ec831cb07ed0099535c7c140cb6338aa62816a x_refsource_MISC