tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper()

Overview

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

tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper()

tee_dyn_shm_alloc_helper() derives nr_pages from a caller-supplied size and passes it to alloc_pages_exact() without checking it. For size == 0 nr_pages is 0, and alloc_pages_exact(0) calls get_order(0), which is documented as undefined and returns BITS_PER_LONG - PAGE_SHIFT. The page allocator then trips its order > MAX_PAGE_ORDER warning and fails the allocation; on a panic_on_warn kernel that ends the boot.

This can be triggered by TEE_IOC_SHM_ALLOC with struct tee_ioctl_shm_alloc_data where size is 0.

Reject a zero page count, as register_shm_helper() already does for the register path.

Affected

• Linux >= cf4441503e20a0c0a36e0a98dcf57de3d3844c91 < e5dc7af9c3a5373ee7a84959126e7dfa9e4ad50d
• Linux >= cf4441503e20a0c0a36e0a98dcf57de3d3844c91 < 65cb86860a80ffc6af897d53f5bd4b1733bca0ec
• Linux >= cf4441503e20a0c0a36e0a98dcf57de3d3844c91 < c2a97703359e25ec7ef8b2b0ef32fb3982add90a
• Linux >= cf4441503e20a0c0a36e0a98dcf57de3d3844c91 < b7f925fd5226deb953c8dcdc9677d3fcc2717c00
• Linux 6.10

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.