diff mbox series

[bpf,3/7] bpf: Refuse unused attributes in bpf_prog_{attach,detach}

Message ID 20231006220655.1653-3-daniel@iogearbox.net (mailing list archive)
State Accepted
Commit ba62d61128bda71fd02622f320ac59d861fc4baa
Delegated to: BPF
Headers show
Series [bpf,1/7] bpf: Fix BPF_PROG_QUERY last field check | expand

Checks

Context Check Description
bpf/vmtest-bpf-VM_Test-0 success Logs for ShellCheck
netdev/series_format warning Series does not have a cover letter
netdev/tree_selection success Clearly marked for bpf
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1365 this patch: 1365
netdev/cc_maintainers fail 2 blamed authors not CCed: ast@kernel.org kuba@kernel.org; 11 maintainers not CCed: song@kernel.org ast@kernel.org andrii@kernel.org kuba@kernel.org yonghong.song@linux.dev jolsa@kernel.org kpsingh@kernel.org john.fastabend@gmail.com sdf@google.com haoluo@google.com martin.lau@linux.dev
netdev/build_clang success Errors and warnings before: 1388 this patch: 1388
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1389 this patch: 1389
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 37 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
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bpf/vmtest-bpf-VM_Test-14 success Logs for test_progs_no_alu32 on aarch64 with gcc
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bpf/vmtest-bpf-VM_Test-17 success Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-18 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-20 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-19 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-22 success Logs for test_progs_parallel on x86_64 with gcc
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bpf/vmtest-bpf-PR success PR summary

Commit Message

Daniel Borkmann Oct. 6, 2023, 10:06 p.m. UTC 
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 mbox series

Patch

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) {