rom_state_paddr is guest provided (caller address of outw(VAPIC_PORT) + writen 16-bit value) and can be influenced to point beyond the end of the host memory backing the guest's RAM. Make sure we do not use this pointer to actually read beyond the limits.
Reading arbitrary guest bytes is harmless, the guest kernel has to manage access to this I/O port anyway. Signed-off-by: Jan Kiszka <[email protected]> --- hw/i386/kvmvapic.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c index 1c2dbf5..2d87600 100644 --- a/hw/i386/kvmvapic.c +++ b/hw/i386/kvmvapic.c @@ -596,6 +596,9 @@ static int vapic_map_rom_writable(VAPICROMState *s) section = memory_region_find(as, 0, 1); /* read ROM size from RAM region */ + if (rom_paddr + 2 >= memory_region_size(section.mr)) { + return -1; + } ram = memory_region_get_ram_ptr(section.mr); rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE; if (rom_size == 0) { -- 1.8.1.1.298.ge7eed54 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
