Re: [Openipmi-developer] [PATCH] ipmi: fix unsigned long underflow

[Corey Minyard]

On 08/07/2017 03:41 AM, Weilong Chen wrote:

Hi Minyard,

I test this patch, it works.

Thanks.



Thanks, I added a Tested-by: for you and it's queued for the next release.
If it's urgent I can send it in now.

I also added this for the stable kernels 3.16 and later.

-corey


On 2017/7/30 10:20, miny...@acm.org wrote:

From: Corey Minyard 

When I set the timeout to a specific value such as 500ms, the timeout
event will not happen in time due to the overflow in function
check_msg_timeout:
...
ent->timeout -= timeout_period;
if (ent->timeout > 0)
return;
...

The type of timeout_period is long, but ent->timeout is unsigned long.
This patch makes the type consistent.

Reported-by: Weilong Chen 
Signed-off-by: Corey Minyard 
---
I like to keep things consistent (though I obviously messed up here)
and keep variables that should be positive unsigned.

But you are right, there is a bug here and some inconsistency.
This patch changes timeout_period to be unsigned and fixes the
check.  Can you try this out?

 drivers/char/ipmi/ipmi_msghandler.c | 10 ++
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c 
b/drivers/char/ipmi/ipmi_msghandler.c

index 810b138..c82d9fd 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -4030,7 +4030,8 @@ smi_from_recv_msg(ipmi_smi_t intf, struct 
ipmi_recv_msg *recv_msg,

 }

 static void check_msg_timeout(ipmi_smi_t intf, struct seq_table *ent,
-  struct list_head *timeouts, long timeout_period,
+  struct list_head *timeouts,
+  unsigned long timeout_period,
   int slot, unsigned long *flags,
   unsigned int *waiting_msgs)
 {
@@ -4043,8 +4044,8 @@ static void check_msg_timeout(ipmi_smi_t intf, 
struct seq_table *ent,

 if (!ent->inuse)
 return;

-ent->timeout -= timeout_period;
-if (ent->timeout > 0) {
+if (timeout_period < ent->timeout) {
+ent->timeout -= timeout_period;
 (*waiting_msgs)++;
 return;
 }
@@ -4110,7 +4111,8 @@ static void check_msg_timeout(ipmi_smi_t intf, 
struct seq_table *ent,

 }
 }

-static unsigned int ipmi_timeout_handler(ipmi_smi_t intf, long 
timeout_period)

+static unsigned int ipmi_timeout_handler(ipmi_smi_t intf,
+ unsigned long timeout_period)
 {
 struct list_head timeouts;
 struct ipmi_recv_msg *msg, *msg2;






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Re: [Openipmi-developer] [PATCH] ipmi: fix unsigned long underflow

[Weilong Chen]

Hi Minyard,

I test this patch, it works.

Thanks.

On 2017/7/30 10:20, miny...@acm.org wrote:

From: Corey Minyard 

When I set the timeout to a specific value such as 500ms, the timeout
event will not happen in time due to the overflow in function
check_msg_timeout:
...
ent->timeout -= timeout_period;
if (ent->timeout > 0)
return;
...

The type of timeout_period is long, but ent->timeout is unsigned long.
This patch makes the type consistent.

Reported-by: Weilong Chen 
Signed-off-by: Corey Minyard 
---
I like to keep things consistent (though I obviously messed up here)
and keep variables that should be positive unsigned.

But you are right, there is a bug here and some inconsistency.
This patch changes timeout_period to be unsigned and fixes the
check.  Can you try this out?

 drivers/char/ipmi/ipmi_msghandler.c | 10 ++
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c 
b/drivers/char/ipmi/ipmi_msghandler.c
index 810b138..c82d9fd 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -4030,7 +4030,8 @@ smi_from_recv_msg(ipmi_smi_t intf, struct ipmi_recv_msg 
*recv_msg,
 }

 static void check_msg_timeout(ipmi_smi_t intf, struct seq_table *ent,
- struct list_head *timeouts, long timeout_period,
+ struct list_head *timeouts,
+ unsigned long timeout_period,
  int slot, unsigned long *flags,
  unsigned int *waiting_msgs)
 {
@@ -4043,8 +4044,8 @@ static void check_msg_timeout(ipmi_smi_t intf, struct 
seq_table *ent,
if (!ent->inuse)
return;

-   ent->timeout -= timeout_period;
-   if (ent->timeout > 0) {
+   if (timeout_period < ent->timeout) {
+   ent->timeout -= timeout_period;
(*waiting_msgs)++;
return;
}
@@ -4110,7 +4111,8 @@ static void check_msg_timeout(ipmi_smi_t intf, struct 
seq_table *ent,
}
 }

-static unsigned int ipmi_timeout_handler(ipmi_smi_t intf, long timeout_period)
+static unsigned int ipmi_timeout_handler(ipmi_smi_t intf,
+unsigned long timeout_period)
 {
struct list_head timeouts;
struct ipmi_recv_msg *msg, *msg2;




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[Openipmi-developer] [PATCH] ipmi: fix unsigned long underflow

[minyard]

From: Corey Minyard 

When I set the timeout to a specific value such as 500ms, the timeout
event will not happen in time due to the overflow in function
check_msg_timeout:
...
ent->timeout -= timeout_period;
if (ent->timeout > 0)
return;
...

The type of timeout_period is long, but ent->timeout is unsigned long.
This patch makes the type consistent.

Reported-by: Weilong Chen 
Signed-off-by: Corey Minyard 
---
I like to keep things consistent (though I obviously messed up here)
and keep variables that should be positive unsigned.

But you are right, there is a bug here and some inconsistency.
This patch changes timeout_period to be unsigned and fixes the
check.  Can you try this out?

 drivers/char/ipmi/ipmi_msghandler.c | 10 ++
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c 
b/drivers/char/ipmi/ipmi_msghandler.c
index 810b138..c82d9fd 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -4030,7 +4030,8 @@ smi_from_recv_msg(ipmi_smi_t intf, struct ipmi_recv_msg 
*recv_msg,
 }
 
 static void check_msg_timeout(ipmi_smi_t intf, struct seq_table *ent,
- struct list_head *timeouts, long timeout_period,
+ struct list_head *timeouts,
+ unsigned long timeout_period,
  int slot, unsigned long *flags,
  unsigned int *waiting_msgs)
 {
@@ -4043,8 +4044,8 @@ static void check_msg_timeout(ipmi_smi_t intf, struct 
seq_table *ent,
if (!ent->inuse)
return;
 
-   ent->timeout -= timeout_period;
-   if (ent->timeout > 0) {
+   if (timeout_period < ent->timeout) {
+   ent->timeout -= timeout_period;
(*waiting_msgs)++;
return;
}
@@ -4110,7 +4111,8 @@ static void check_msg_timeout(ipmi_smi_t intf, struct 
seq_table *ent,
}
 }
 
-static unsigned int ipmi_timeout_handler(ipmi_smi_t intf, long timeout_period)
+static unsigned int ipmi_timeout_handler(ipmi_smi_t intf,
+unsigned long timeout_period)
 {
struct list_head timeouts;
struct ipmi_recv_msg *msg, *msg2;
-- 
2.7.4


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