From 7855a721d9db4a2c0a64758ac08e73aa627fcecd Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 20 Mar 2020 17:22:58 +0100 Subject: [PATCH] bpf: Explicitly memset some bpf info structures declared on the stack 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200320162258.GA794295@kroah.com Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/syscall.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8081e233a564..21073682061d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1364,7 +1364,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, 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(struct bpf_prog *prog, 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 bpf_map *map, 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 bpf_map *map, 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; -- 2.20.1