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[Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device |
Date: |
Fri, 5 Apr 2013 11:51:01 +0200 |
What is the highest addressable sector on an empty CD-ROM? Nothing is
addressable so produce an error.
This patch prevents a divide-by-zero in ide_set_sector() since
s->sectors and s->heads would be 0. Not to mention that a sector=-1
argument would be nonsense.
Note that WIN_READ_NATIVE_MAX can be triggered using hdparm -N 1024
/dev/cdrom. The LBA bit will be set to 1 though, so the only easy way
to go down the ide_set_sector() CHS code path which divides by zero is
to comment out the s->select & 0x40 case for testing.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/ide/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/ide/core.c b/hw/ide/core.c
index 3743dc3..77f1379 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1262,6 +1262,10 @@ void ide_exec_cmd(IDEBus *bus, uint32_t val)
lba48 = 1;
/* fall through */
case WIN_READ_NATIVE_MAX:
+ /* Refuse if no sectors are addressable (e.g. medium not inserted) */
+ if (s->nb_sectors == 0) {
+ goto abort_cmd;
+ }
ide_cmd_lba48_transform(s, lba48);
ide_set_sector(s, s->nb_sectors - 1);
s->status = READY_STAT | SEEK_STAT;
--
1.8.1.4
- [Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device,
Stefan Hajnoczi <=
Re: [Qemu-devel] [PATCH] ide: refuse WIN_READ_NATIVE_MAX on empty device, Stefan Hajnoczi, 2013/04/10