From: Daniel Borkmann <daniel@iogearbox.net>
To: bpf@vger.kernel.org
Cc: lmb@isovalent.com, martin.lau@kernel.org,
Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH bpf 3/7] bpf: Refuse unused attributes in bpf_prog_{attach,detach}
Date: Sat, 7 Oct 2023 00:06:51 +0200 [thread overview]
Message-ID: <20231006220655.1653-3-daniel@iogearbox.net> (raw)
In-Reply-To: <20231006220655.1653-1-daniel@iogearbox.net>
From: Lorenz Bauer <lmb@isovalent.com>
The recently added tcx attachment extended the BPF UAPI for attaching and
detaching by a couple of fields. Those fields are currently only supported
for tcx, other types like cgroups and flow dissector silently ignore the
new fields except for the new flags.
This is problematic once we extend bpf_mprog to older attachment types, since
it's hard to figure out whether the syscall really was successful if the
kernel silently ignores non-zero values.
Explicitly reject non-zero fields relevant to bpf_mprog for attachment types
which don't use the latter yet.
Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/syscall.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 453a43695a23..d77b2f8b9364 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3796,7 +3796,6 @@ static int bpf_prog_attach(const union bpf_attr *attr)
{
enum bpf_prog_type ptype;
struct bpf_prog *prog;
- u32 mask;
int ret;
if (CHECK_ATTR(BPF_PROG_ATTACH))
@@ -3805,10 +3804,16 @@ static int bpf_prog_attach(const union bpf_attr *attr)
ptype = attach_type_to_prog_type(attr->attach_type);
if (ptype == BPF_PROG_TYPE_UNSPEC)
return -EINVAL;
- mask = bpf_mprog_supported(ptype) ?
- BPF_F_ATTACH_MASK_MPROG : BPF_F_ATTACH_MASK_BASE;
- if (attr->attach_flags & ~mask)
- return -EINVAL;
+ if (bpf_mprog_supported(ptype)) {
+ if (attr->attach_flags & ~BPF_F_ATTACH_MASK_MPROG)
+ return -EINVAL;
+ } else {
+ if (attr->attach_flags & ~BPF_F_ATTACH_MASK_BASE)
+ return -EINVAL;
+ if (attr->relative_fd ||
+ attr->expected_revision)
+ return -EINVAL;
+ }
prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
if (IS_ERR(prog))
@@ -3878,6 +3883,10 @@ static int bpf_prog_detach(const union bpf_attr *attr)
if (IS_ERR(prog))
return PTR_ERR(prog);
}
+ } else if (attr->attach_flags ||
+ attr->relative_fd ||
+ attr->expected_revision) {
+ return -EINVAL;
}
switch (ptype) {
--
2.34.1
next prev parent reply other threads:[~2023-10-06 22:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-06 22:06 [PATCH bpf 1/7] bpf: Fix BPF_PROG_QUERY last field check Daniel Borkmann
2023-10-06 22:06 ` [PATCH bpf 2/7] bpf: Handle bpf_mprog_query with NULL entry Daniel Borkmann
2023-10-06 22:06 ` Daniel Borkmann [this message]
2023-10-06 22:06 ` [PATCH bpf 4/7] selftests/bpf: Test bpf_mprog query API via libbpf and raw syscall Daniel Borkmann
2023-10-06 22:06 ` [PATCH bpf 5/7] selftests/bpf: Adapt assert_mprog_count to always expect 0 count Daniel Borkmann
2023-10-06 22:06 ` [PATCH bpf 6/7] selftests/bpf: Test query on empty mprog and pass revision into attach Daniel Borkmann
2023-10-06 22:06 ` [PATCH bpf 7/7] selftests/bpf: Make seen_tc* variable tests more robust Daniel Borkmann
2023-10-07 5:20 ` [PATCH bpf 1/7] bpf: Fix BPF_PROG_QUERY last field check patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231006220655.1653-3-daniel@iogearbox.net \
--to=daniel@iogearbox.net \
--cc=bpf@vger.kernel.org \
--cc=lmb@isovalent.com \
--cc=martin.lau@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).