RDMA/ucma: Limit possible option size

[ Upstream commit 6a21dfc0d0db7b7e0acedce67ca533a6eb19283c ]

Users of ucma are supposed to provide size of option level,
in most paths it is supposed to be equal to u8 or u16, but
it is not the case for the IB path record, where it can be
multiple of struct ib_path_rec_data.

This patch takes simplest possible approach and prevents providing
values more than possible to allocate.

Reported-by: syzbot+a38b0e9f694c379ca7ce@syzkaller.appspotmail.com
Fixes: 7ce86409adcd ("RDMA/ucma: Allow user space to set service type")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 81dd84d0b68b545824788b9d7de99403b1befffe..1ce5e1cc81016472aee271c68684f0757f672fa7 100644 (file)
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1187,6 +1187,9 @@ static ssize_t ucma_set_option(struct ucma_file *file, const char __user *inbuf,
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
 
+       if (unlikely(cmd.optval > KMALLOC_MAX_SIZE))
+               return -EINVAL;
+
        optval = memdup_user((void __user *) (unsigned long) cmd.optval,
                             cmd.optlen);
        if (IS_ERR(optval)) {