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authorKui-Feng Lee <thinker.li@gmail.com>2024-01-26 03:31:13 +0100
committerMartin KaFai Lau <martin.lau@kernel.org>2024-01-26 05:49:59 +0100
commite6be8cd5d3cf54ccd0ae66027d6f4697b15f4c3e (patch)
treeea60dfda94c8a06e4c14f90a4900b7167121d847 /kernel/bpf
parentbpf: One more maintainer for libbpf and BPF selftests (diff)
downloadlinux-e6be8cd5d3cf54ccd0ae66027d6f4697b15f4c3e.tar.xz
linux-e6be8cd5d3cf54ccd0ae66027d6f4697b15f4c3e.zip
bpf: Fix error checks against bpf_get_btf_vmlinux().
In bpf_struct_ops_map_alloc, it needs to check for NULL in the returned pointer of bpf_get_btf_vmlinux() when CONFIG_DEBUG_INFO_BTF is not set. ENOTSUPP is used to preserve the same behavior before the struct_ops kmod support. In the function check_struct_ops_btf_id(), instead of redoing the bpf_get_btf_vmlinux() that has already been done in syscall.c, the fix here is to check for prog->aux->attach_btf_id. BPF_PROG_TYPE_STRUCT_OPS must require attach_btf_id and syscall.c guarantees a valid attach_btf as long as attach_btf_id is set. When attach_btf_id is not set, this patch returns -ENOTSUPP because it is what the selftest in test_libbpf_probe_prog_types() and libbpf_probes.c are expecting for feature probing purpose. Changes from v1: - Remove an unnecessary NULL check in check_struct_ops_btf_id() Reported-by: syzbot+88f0aafe5f950d7489d7@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/00000000000040d68a060fc8db8c@google.com/ Reported-by: syzbot+1336f3d4b10bcda75b89@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/00000000000026353b060fc21c07@google.com/ Fixes: fcc2c1fb0651 ("bpf: pass attached BTF to the bpf_struct_ops subsystem") Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com> Link: https://lore.kernel.org/r/20240126023113.1379504-1-thinker.li@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/bpf_struct_ops.c2
-rw-r--r--kernel/bpf/verifier.c5
2 files changed, 6 insertions, 1 deletions
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index defc052e4622..0decd862dfe0 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -669,6 +669,8 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
btf = bpf_get_btf_vmlinux();
if (IS_ERR(btf))
return ERR_CAST(btf);
+ if (!btf)
+ return ERR_PTR(-ENOTSUPP);
}
st_ops_desc = bpf_struct_ops_find_value(btf, attr->btf_vmlinux_value_type_id);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index fe833e831cb6..c5d68a9d8acc 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -20298,7 +20298,10 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
return -EINVAL;
}
- btf = prog->aux->attach_btf ?: bpf_get_btf_vmlinux();
+ if (!prog->aux->attach_btf_id)
+ return -ENOTSUPP;
+
+ btf = prog->aux->attach_btf;
if (btf_is_module(btf)) {
/* Make sure st_ops is valid through the lifetime of env */
env->attach_btf_mod = btf_try_get_module(btf);