diff options
| -rw-r--r-- | fs/userfaultfd.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index b5074a344635..87d31921b66c 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1285,6 +1285,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, struct uffdio_api uffdio_api; void __user *buf = (void __user *)arg; int ret; + __u64 features; ret = -EINVAL; if (ctx->state != UFFD_STATE_WAIT_API) @@ -1292,21 +1293,23 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, ret = -EFAULT; if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api))) goto out; - if (uffdio_api.api != UFFD_API || - (uffdio_api.features & ~UFFD_API_FEATURES)) { + features = uffdio_api.features; + if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES)) { memset(&uffdio_api, 0, sizeof(uffdio_api)); if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api))) goto out; ret = -EINVAL; goto out; } - uffdio_api.features &= UFFD_API_FEATURES; + /* report all available features and ioctls to userland */ + uffdio_api.features = UFFD_API_FEATURES; uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api))) goto out; ctx->state = UFFD_STATE_RUNNING; - ctx->features = uffd_ctx_features(uffdio_api.features); + /* only enable the requested features for this uffd context */ + ctx->features = uffd_ctx_features(features); ret = 0; out: return ret; |