In the case that size1 was zero, because of the explicit 'end1 > addr' check, the range check would fail and the error message would read as shown below. The correct comparison is 'end1 >= addr' (or 'addr <= end1').
EDU: DMA range 0x40000-0x3ffff out of bounds (0x40000-0x3ffff)! At the opposite end, in the case that size1 was 4096, within() would fail because of the non-inclusive check 'end1 < end2', which should have been 'end1 <= end2'. The error message would previously say EDU: DMA range 0x40000-0x40fff out of bounds (0x40000-0x40fff)! Note: the original change (and error message) was when parameters were uint32_t. Signed-off-by: Chris Friedt <chrisfri...@gmail.com> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1254 --- hw/misc/edu.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/hw/misc/edu.c b/hw/misc/edu.c index e935c418d4..a6f5f97f13 100644 --- a/hw/misc/edu.c +++ b/hw/misc/edu.c @@ -103,19 +103,18 @@ static void edu_lower_irq(EduState *edu, uint32_t val) } } -static bool within(uint64_t addr, uint64_t start, uint64_t end) -{ - return start <= addr && addr < end; -} - static void edu_check_range(uint64_t addr, uint64_t size1, uint64_t start, uint64_t size2) { uint64_t end1 = addr + size1; uint64_t end2 = start + size2; - if (within(addr, start, end2) && - end1 > addr && within(end1, start, end2)) { + /* + * 1. ensure we aren't overflowing + * 2. ensure that [start, end2) is within [addr, end1) + */ + if (end1 >= addr && end2 >= start && start >= addr && end2 <= end1) + { return; } -- 2.36.1
