AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2025-02-23 13:24:21 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity

bpf: Forbid trampoline attach for functions with variable arguments

Browse Source 
[ Upstream commit 31379397dcc364a59ce764fabb131b645c43e340 ]

We can't currently allow to attach functions with variable arguments.
The problem is that we should save all the registers for arguments,
which is probably doable, but if caller uses more than 6 arguments,
we need stack data, which will be wrong, because of the extra stack
frame we do in bpf trampoline, so we could crash.

Also currently there's malformed trampoline code generated for such
functions at the moment as described in:

  https://lore.kernel.org/bpf/20210429212834.82621-1-jolsa@kernel.org/

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210505132529.401047-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jiri Olsa 2021-05-05 15:25:29 +02:00 committed by Greg Kroah-Hartman
parent fb91ab403e
commit 584b2c7ce2
1 changed files with 12 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
kernel/bpf/btf.c
View File

@ -4960,6 +4960,12 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
m->ret_size = ret;
for (i = 0; i < nargs; i++) {
if (i == nargs - 1 && args[i].type == 0) {
bpf_log(log,
"The function %s with variable args is unsupported.\n",
tname);
return -EINVAL;
}
ret = __get_type_size(btf, args[i].type, &t);
if (ret < 0) {
bpf_log(log,
@ -4967,6 +4973,12 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
return -EINVAL;
}
if (ret == 0) {
bpf_log(log,
"The function %s has malformed void argument.\n",
tname);
return -EINVAL;
}
m->arg_size[i] = ret;
}
m->nr_args = nargs;