diff mbox series

[bpf-next,v3,13/17] bpf: Fix kfunc callback register type handling

Message ID 20230912233214.1518551-14-memxor@gmail.com (mailing list archive)
State Accepted
Commit 06d686f771ddc27a8554cd8f5b22e071040dc90e
Delegated to: BPF
Headers show
Series Exceptions - 1/2 | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1354 this patch: 1354
netdev/cc_maintainers warning 6 maintainers not CCed: jolsa@kernel.org haoluo@google.com sdf@google.com john.fastabend@gmail.com kpsingh@kernel.org song@kernel.org
netdev/build_clang success Errors and warnings before: 1367 this patch: 1367
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: 1377 this patch: 1377
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns
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-next-PR success PR summary

Commit Message

Kumar Kartikeya Dwivedi Sept. 12, 2023, 11:32 p.m. UTC 
The kfunc code to handle KF_ARG_PTR_TO_CALLBACK does not check the reg
type before using reg->subprogno. This can accidently permit invalid
pointers from being passed into callback helpers (e.g. silently from
different paths). Likewise, reg->subprogno from the per-register type
union may not be meaningful either. We need to reject any other type
except PTR_TO_FUNC.

Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Fixes: 5d92ddc3de1b ("bpf: Add callback validation to kfunc verifier logic")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 kernel/bpf/verifier.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 21e37e46d792..dff8c43dea0c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11407,6 +11407,10 @@  static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
 			break;
 		}
 		case KF_ARG_PTR_TO_CALLBACK:
+			if (reg->type != PTR_TO_FUNC) {
+				verbose(env, "arg%d expected pointer to func\n", i);
+				return -EINVAL;
+			}
 			meta->subprogno = reg->subprogno;
 			break;
 		case KF_ARG_PTR_TO_REFCOUNTED_KPTR: