From: Greg Kroah-Hartman gregkh@linuxfoundation.org
commit 739790605705ddcf18f21782b9c99ad7d53a8c11 upstream.
do_prlimit() adds the user-controlled resource value to a pointer that will subsequently be dereferenced. In order to help prevent this codepath from being used as a spectre "gadget" a barrier needs to be added after checking the range.
Reported-by: Jordy Zomer jordyzomer@google.com Tested-by: Jordy Zomer jordyzomer@google.com Suggested-by: Linus Torvalds torvalds@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sys.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/kernel/sys.c +++ b/kernel/sys.c @@ -1548,6 +1548,8 @@ int do_prlimit(struct task_struct *tsk,
if (resource >= RLIM_NLIMITS) return -EINVAL; + resource = array_index_nospec(resource, RLIM_NLIMITS); + if (new_rlim) { if (new_rlim->rlim_cur > new_rlim->rlim_max) return -EINVAL;