From: Joshua Daley <[email protected]>
In the dir_rem[level] == 0 case, level is decremented, then
a virtio_read() is issued on sec_loc[level]. If level is -1, then the
4 bytes before the static sec_loc array are read, and the virtio_read()
is issued on that garbage block number.
Guard the call to virtio_read() against the value of level to prevent
this.
Fixes: 869648e87eeb ("pc-bios/s390-ccw: El Torito 16-bit boot image size field
workaround")
Signed-off-by: Joshua Daley <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
---
pc-bios/s390-ccw/bootmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 420ee32eff..ed6e8cbbc7 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -902,7 +902,7 @@ static inline long iso_get_file_size(uint32_t load_rba)
if (dir_rem[level] == 0) {
/* Nothing remaining */
level--;
- if (virtio_read(sec_loc[level], temp)) {
+ if (level >= 0 && virtio_read(sec_loc[level], temp)) {
puts("Failed to read ISO directory");
return -EIO;
}
--
2.53.0
