Messages in this thread Patch in this message | | | From | vegard.nossum@oracle ... | Subject | [PATCH] sched: fix information leak in sys_sched_getattr() | Date | Sun, 16 Feb 2014 22:24:17 +0100 |
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From: Vegard Nossum <vegard.nossum@oracle.com>
We're copying the on-stack structure to userspace, but forgot to give the right number of bytes to copy. This allows the calling process to obtain up to PAGE_SIZE bytes from the stack (and possibly adjacent kernel memory).
This fix copies only as much as we actually have on the stack (attr->size defaults to the size of the struct) and leaves the rest of the userspace-provided buffer untouched.
Found using kmemcheck + trinity.
Fixes: d50dde5a10f30 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI") Cc: Dario Faggioli <raistlin@linux.it> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b46131e..ac939c3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3786,7 +3786,7 @@ static int sched_read_attr(struct sched_attr __user *uattr, attr->size = usize; } - ret = copy_to_user(uattr, attr, usize); + ret = copy_to_user(uattr, attr, attr->size); if (ret) return -EFAULT; -- 1.7.10.4
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