| Message ID | 20200717133847.10974-1-f4bug@amsat.org |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC,PATCH-for-5.1,v2] hw/ide: Avoid #DIV/0! FPU exception by setting CD-ROM sector count | expand |
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c index 27ff1f7f66..005d73bdb9 100644 --- a/hw/ide/qdev.c +++ b/hw/ide/qdev.c @@ -201,6 +201,15 @@ static void ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind, Error **errp) errp)) { return; } + } else { + uint64_t nb_sectors; + + blk_get_geometry(dev->conf.blk, &nb_sectors); + if (!nb_sectors) { + warn_report("Drive image of size zero is unsupported for 'ide-cd', " + "use at your own risk ¯\\_(ツ)_/¯"); + } + dev->conf.secs = nb_sectors; } if (!blkconf_apply_backend_options(&dev->conf, kind == IDE_CD, kind != IDE_CD, errp)) {
libFuzzer found an undefined behavior (#DIV/0!) in ide_set_sector() when using a CD-ROM (reproducer available on the BugLink): UndefinedBehaviorSanitizer:DEADLYSIGNAL ==12163==ERROR: UndefinedBehaviorSanitizer: FPE on unknown address 0x5616279cffdc (pc 0x5616279cffdc bp 0x7ffcdaabae90 sp 0x7ffcdaabae30 T12163) Fix by initializing the CD-ROM number of sectors in ide_dev_initfn(). Reported-by: Alexander Bulekov <alxndr@bu.edu> Fixes: b2df431407 ("ide scsi: Mess with geometry only for hard disk devices") BugLink: https://bugs.launchpad.net/qemu/+bug/1887309 Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- Since v1: - Allow zero-sized drive images (not sure why we need them) but display a friendly message that this is unsupported Unrelated but interesting: http://www.physics.udel.edu/~watson/scen103/cdsoln.html --- hw/ide/qdev.c | 9 +++++++++ 1 file changed, 9 insertions(+)