[lttng-dev] [PATCH lttng-modules] Fix: copy_from_user size when limited allocation

[Mathieu Desnoyers]

merged into master, thanks!

Mathieu

----- On May 2, 2016, at 4:48 PM, Julien Desfossez jdesfossez at efficios.com wrote:

> We restrict the memory allocation to one page, but in two syscalls we were
> using the wrong size in the copy_from_user.
> 
> Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
> ---
> instrumentation/syscalls/headers/syscalls_pointers_override.h | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h
> b/instrumentation/syscalls/headers/syscalls_pointers_override.h
> index dd6f954..4a69fc3 100644
> --- a/instrumentation/syscalls/headers/syscalls_pointers_override.h
> +++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h
> @@ -418,8 +418,7 @@ static struct lttng_type lttng_pollfd_elem = {
> 		if (!tp_locvar->fds)							\
> 			goto error;							\
> 		err = lib_ring_buffer_copy_from_user_check_nofault(			\
> -			tp_locvar->fds, ufds,						\
> -			nfds * sizeof(struct pollfd));					\
> +			tp_locvar->fds, ufds, tp_locvar->alloc_fds);			\
> 		if (err != 0)								\
> 			goto error;							\
> 	}										\
> @@ -772,7 +771,7 @@ static struct lttng_type lttng_epoll_wait_elem = {
> 										\
> 		err = lib_ring_buffer_copy_from_user_check_nofault(		\
> 			tp_locvar->events, uevents,				\
> -			maxevents * sizeof(struct epoll_event));		\
> +			maxalloc * sizeof(struct epoll_event));			\
> 		if (err != 0)							\
> 			tp_locvar->fds_length = 0;				\
> 	}									\
> --
> 1.9.1

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com