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Subject[PATCH 1/1] setitimer : Return -EFAULT if the user pointer "value" is NULL
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Return -EFAULT if user  pointer "value" is  NULL.

In the current timer implementation

setitimer (which, NULL, NULL)

is equal to

timer.it_value.tv_sec = 0;
timer.it_value.tv_usec = 0;
timer.it_interval.tv_sec = 0;
timer.it_interval.tv_usec = 0;

setitimer (which, &timer, NULL);

setitimer man page says "The function setitimer() sets the specified timer to the value in new_value".

If the new_value is NULL, kernel should not set timer with tv_sec = 0 and tv_usec = 0, instead return -EFAULT.

Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com>
---
kernel/itimer.c | 17 ++++++++---------
1 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/kernel/itimer.c b/kernel/itimer.c
index 22000c3..f356bdf 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -279,19 +279,18 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
struct itimerval __user *, ovalue)
{
struct itimerval set_buffer, get_buffer;
- int error;
+ int error = -EFAULT;

if (value) {
if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
return -EFAULT;
- } else
- memset((char *) &set_buffer, 0, sizeof(set_buffer));

- error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
- if (error || !ovalue)
- return error;
+ error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
+ if (error || !ovalue)
+ return error;

- if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
- return -EFAULT;
- return 0;
+ if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
+ return -EFAULT;
+ }
+ return error;
}
--
1.7.3.4


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