Security: Improper Input Validation in the function utee_cryp_obj_alloc

[c01dkit]

Affected components：

affected source code file: /tee/tee/tee_svc_cryp.c, affected functions: utee_cryp_obj_alloc
affected source code file: /tee/tee/tee_obj.c, affected functions: tee_obj_alloc and tee_obj_free

Attack vector(s)

One way to exploit the vulnerability, invoking the function TEE_AllocateOperation and TEE_Realloc with a large size to disturb the heap layout, and invoke TEE_AllocateOperation again.

Suggested description of the vulnerability for use in the CVE

Improper Input Validation vulnerablity in the function tee_obj_free in Samsung Electronics mTower v0.3.0 (and earlier) allows a trusted application to trigger a Denial of Service (DoS) via invoking the function TEE_AllocateOperation with a disturbed heap layout.

Discoverer(s)/Credits

SyzTrust

Reference(s)

https://github.com/Samsung/mTower

mTower/tee/tee/tee_svc_cryp.c

Line 1248 in efd3670

TEE_Result utee_cryp_obj_alloc(unsigned long obj_type,

mTower/tee/tee/tee_obj.c

Line 109 in efd3670

free(o->attr);

Additional information

As shown in POC, the calloc function in tee_obj_alloc does not return a buffer with all bits zero as expected when the heap layout was disturbed in mTower on a real IoT hardware (such as Numaker-PFM-M2351). Executing the statement free(o->attr) then will free an invalid pointer, which will crash the trusted execution environment kernel and cause a Denial of Service (DoS).

PoC

poc_14.zip

THANK YOU FOR CONTRIBUTIONS IN MTOWER TEE OS!