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From 32f493a17f62a2b144790b7b46054b9b4ee43f68 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri, 20 Mar 2020 17:18:56 +0100
Subject: [PATCH 2/2] bpf: explicitly memset some bpf info structures declared
on the stack
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>
---
kernel/bpf/btf.c | 3 ++-
kernel/bpf/syscall.c | 6 ++++--
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 787140095e58..2fc945fcf952 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4564,7 +4564,7 @@ int btf_get_info_by_fd(const struct btf *btf,
union bpf_attr __user *uattr)
{
struct bpf_btf_info __user *uinfo;
- struct bpf_btf_info info = {};
+ struct bpf_btf_info info;
u32 info_copy, btf_copy;
void __user *ubtf;
u32 uinfo_len;
@@ -4573,6 +4573,7 @@ int btf_get_info_by_fd(const struct btf *btf,
uinfo_len = attr->info.info_len;
info_copy = min_t(u32, uinfo_len, sizeof(info));
+ memset(&info, 0, sizeof(info));
if (copy_from_user(&info, uinfo, info_copy))
return -EFAULT;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a4b1de8ea409..84213cc5d016 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2787,7 +2787,7 @@ 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;
struct bpf_prog_stats stats;
char __user *uinsns;
@@ -2799,6 +2799,7 @@ 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;
@@ -3062,7 +3063,7 @@ 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;
@@ -3071,6 +3072,7 @@ 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;
--
2.25.2
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