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bpf: Explicitly memset some bpf info structures declared on the stack

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commit 5c6f258879 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>
This commit is contained in:
Greg Kroah-Hartman 2020-03-20 17:22:58 +01:00
parent ba1ebf3aef
commit 7855a721d9
1 changed files with 4 additions and 2 deletions
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6
kernel/bpf/syscall.c
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@ -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;