diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2023-10-07 00:06:50 +0200 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2023-10-06 17:11:20 -0700 |
| commit | edfa9af0a73ecc2000d7bb81d0b0fd3158cc9a65 (patch) | |
| tree | 2fa48698f2b0cfb93be08203381e12cc6b5c4c03 | |
| parent | a4fe78386afb94780f8e6fcd10a67c4d4dfe4da8 (diff) | |
| download | linux-edfa9af0a73ecc2000d7bb81d0b0fd3158cc9a65.tar.gz | |
bpf: Handle bpf_mprog_query with NULL entry
Improve consistency for bpf_mprog_query() API and let the latter also handle
a NULL entry as can be the case for tcx. Instead of returning -ENOENT, we
copy a count of 0 and revision of 1 to user space, so that this can be fed
into a subsequent bpf_mprog_attach() call as expected_revision. A BPF self-
test as part of this series has been added to assert this case.
Suggested-by: Lorenz Bauer <lmb@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20231006220655.1653-2-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
| -rw-r--r-- | kernel/bpf/mprog.c | 10 | ||||
| -rw-r--r-- | kernel/bpf/tcx.c | 8 |
2 files changed, 7 insertions, 11 deletions
diff --git a/kernel/bpf/mprog.c b/kernel/bpf/mprog.c index 007d98c799e2d0..1394168062e856 100644 --- a/kernel/bpf/mprog.c +++ b/kernel/bpf/mprog.c @@ -401,14 +401,16 @@ int bpf_mprog_query(const union bpf_attr *attr, union bpf_attr __user *uattr, struct bpf_mprog_cp *cp; struct bpf_prog *prog; const u32 flags = 0; + u32 id, count = 0; + u64 revision = 1; int i, ret = 0; - u32 id, count; - u64 revision; if (attr->query.query_flags || attr->query.attach_flags) return -EINVAL; - revision = bpf_mprog_revision(entry); - count = bpf_mprog_total(entry); + if (entry) { + revision = bpf_mprog_revision(entry); + count = bpf_mprog_total(entry); + } if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) return -EFAULT; if (copy_to_user(&uattr->query.revision, &revision, sizeof(revision))) diff --git a/kernel/bpf/tcx.c b/kernel/bpf/tcx.c index 13f0b5dc8262a0..1338a13a8b64b0 100644 --- a/kernel/bpf/tcx.c +++ b/kernel/bpf/tcx.c @@ -123,7 +123,6 @@ int tcx_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { bool ingress = attr->query.attach_type == BPF_TCX_INGRESS; struct net *net = current->nsproxy->net_ns; - struct bpf_mprog_entry *entry; struct net_device *dev; int ret; @@ -133,12 +132,7 @@ int tcx_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) ret = -ENODEV; goto out; } - entry = tcx_entry_fetch(dev, ingress); - if (!entry) { - ret = -ENOENT; - goto out; - } - ret = bpf_mprog_query(attr, uattr, entry); + ret = bpf_mprog_query(attr, uattr, tcx_entry_fetch(dev, ingress)); out: rtnl_unlock(); return ret; |