As a part of MANA hardening for CVM, add validation for the doorbell
ID (db_id) received from hardware in the GDMA_REGISTER_DEVICE response
to prevent out-of-bounds memory access when calculating the doorbell
page address.
In mana_gd_ring_doorbell(), the doorbell page address is calculated as:
addr = db_page_base + db_page_size * db_index
= (bar0_va + db_page_off) + db_page_size * db_index
A hardware could return values that cause this address to fall outside
the BAR0 MMIO region. In Confidential VM environments, hardware responses
cannot be fully trusted.
Add the following validations:
- Store the BAR0 size (bar0_size) in gdma_context during probe.
- Validate the doorbell page offset (db_page_off) read from device
registers does not exceed bar0_size during initialization, converting
mana_gd_init_registers() to return an error code.
- Validate db_id from GDMA_REGISTER_DEVICE response against the
maximum number of doorbell pages that fit within BAR0.
Signed-off-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
Link: https://patch.msgid.link/20260306211212.543376-1-ernis@linux.microsoft.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
89fe91c659