From 61f259821dd3306e49b7d42a3f90fb5a4ff3351b Mon Sep 17 00:00:00 2001 From: "Luck, Tony" Date: Tue, 30 Jul 2019 21:39:57 -0700 Subject: [PATCH] IB/core: Add mitigation for Spectre V1 Some processors may mispredict an array bounds check and speculatively access memory that they should not. With a user supplied array index we like to play things safe by masking the value with the array size before it is used as an index. Signed-off-by: Tony Luck Link: https://lore.kernel.org/r/20190731043957.GA1600@agluck-desk2.amr.corp.intel.com Signed-off-by: Doug Ledford --- drivers/infiniband/core/user_mad.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 9f8a48016b41..ffdeaf6e0b68 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -49,6 +49,7 @@ #include #include #include +#include #include @@ -884,11 +885,14 @@ static int ib_umad_unreg_agent(struct ib_umad_file *file, u32 __user *arg) if (get_user(id, arg)) return -EFAULT; + if (id >= IB_UMAD_MAX_AGENTS) + return -EINVAL; mutex_lock(&file->port->file_mutex); mutex_lock(&file->mutex); - if (id >= IB_UMAD_MAX_AGENTS || !__get_agent(file, id)) { + id = array_index_nospec(id, IB_UMAD_MAX_AGENTS); + if (!__get_agent(file, id)) { ret = -EINVAL; goto out; } -- 2.30.2