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Commit 7855a721 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200320162258.GA794295@kroah.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ba1ebf3a

kernel/bpf/syscall.c

+4 −2
Original line number Diff line number Diff line
@@ -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;