From: Greg Kroah-Hartman gregkh@linuxfoundation.org
commit 5c6f25887963f15492b604dd25cb149c501bbabf upstream.
Trying to initialize a structure with "= {};" will not always clean out all padding locations in a structure. So be explicit and call memset to initialize everything for a number of bpf information structures that are then copied from userspace, sometimes from smaller memory locations than the size of the structure.
Reported-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Yonghong Song yhs@fb.com Link: https://lore.kernel.org/bpf/20200320162258.GA794295@kroah.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/bpf/syscall.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1364,7 +1364,7 @@ static int bpf_prog_get_info_by_fd(struc union bpf_attr __user *uattr) { struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info); - struct bpf_prog_info info = {}; + struct bpf_prog_info info; u32 info_len = attr->info.info_len; char __user *uinsns; u32 ulen; @@ -1375,6 +1375,7 @@ static int bpf_prog_get_info_by_fd(struc return err; info_len = min_t(u32, sizeof(info), info_len);
+ memset(&info, 0, sizeof(info)); if (copy_from_user(&info, uinfo, info_len)) return -EFAULT;
@@ -1420,7 +1421,7 @@ static int bpf_map_get_info_by_fd(struct union bpf_attr __user *uattr) { struct bpf_map_info __user *uinfo = u64_to_user_ptr(attr->info.info); - struct bpf_map_info info = {}; + struct bpf_map_info info; u32 info_len = attr->info.info_len; int err;
@@ -1429,6 +1430,7 @@ static int bpf_map_get_info_by_fd(struct return err; info_len = min_t(u32, sizeof(info), info_len);
+ memset(&info, 0, sizeof(info)); info.type = map->map_type; info.id = map->id; info.key_size = map->key_size;