The commit eca2040972b4 introduced a backward compatibility issue in
the function ioprio_check_cap.
Before the change, if ioprio contains a level greater than 0x7, it was
treated as -EINVAL:
data = ioprio & 0x1FFF
if data >= 0x7, return -EINVAL
Since the change, if ioprio contains a level greater than 0x7 say 0x8
it is calculated as 0x0:
level = ioprio & 0x7
To maintain backward compatibility the kernel should return -EINVAL in
the above case as well.
Fixes: eca2040972b4 ("scsi: block: ioprio: Clean up interface definition")
Signed-off-by: Ajay Kaher <ajay.kaher@xxxxxxxxxxxx>
---
block/ioprio.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/block/ioprio.c b/block/ioprio.c
index 73301a2..f08e76b 100644
--- a/block/ioprio.c
+++ b/block/ioprio.c
@@ -30,6 +30,15 @@
#include <linux/security.h>
#include <linux/pid_namespace.h>
+static inline int ioprio_check_level(int ioprio, int max_level)
+{
+ int data = IOPRIO_PRIO_DATA(ioprio);
+
+ if (IOPRIO_BAD_VALUE(data, max_level))
+ return -EINVAL;
+ return 0;
+}
+
int ioprio_check_cap(int ioprio)
{
int class = IOPRIO_PRIO_CLASS(ioprio);
@@ -49,7 +58,7 @@ int ioprio_check_cap(int ioprio)
fallthrough;
/* rt has prio field too */
case IOPRIO_CLASS_BE:
- if (level >= IOPRIO_NR_LEVELS)
+ if (ioprio_check_level(ioprio, IOPRIO_NR_LEVELS))
return -EINVAL;
break;
case IOPRIO_CLASS_IDLE:
--
2.45.1
