diff mbox series

[bpf-next,08/10] bpf: enforce precision of R0 on program/async callback return

Message ID 20231122011656.1105943-9-andrii@kernel.org (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series BPF verifier retval logic fixes | expand

Checks

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bpf/vmtest-bpf-next-PR success PR summary
netdev/series_format success Posting correctly formatted
netdev/codegen success Generated files up to date
netdev/tree_selection success Clearly marked for bpf-next
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: 1146 this patch: 1146
netdev/cc_maintainers warning 8 maintainers not CCed: yonghong.song@linux.dev john.fastabend@gmail.com song@kernel.org haoluo@google.com jolsa@kernel.org kpsingh@kernel.org martin.lau@linux.dev sdf@google.com
netdev/build_clang success Errors and warnings before: 1162 this patch: 1162
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 No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1173 this patch: 1173
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 10 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
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Commit Message

Andrii Nakryiko Nov. 22, 2023, 1:16 a.m. UTC 
Given we enforce a valid range for program and async callback return
value, we must mark R0 as precise to avoid incorrect state pruning.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 kernel/bpf/verifier.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Eduard Zingerman Nov. 22, 2023, 3:13 p.m. UTC | #1 
On Tue, 2023-11-21 at 17:16 -0800, Andrii Nakryiko wrote:
> Given we enforce a valid range for program and async callback return
> value, we must mark R0 as precise to avoid incorrect state pruning.
> 
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---

Acked-by: Eduard Zingerman <eddyz87@gmail.com>

[...]
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 87d720d44e0c..1a0a545aec9c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -15003,6 +15003,10 @@  static int check_return_code(struct bpf_verifier_env *env, int regno, const char
 		return -EINVAL;
 	}
 
+	err = mark_chain_precision(env, regno);
+	if (err)
+		return err;
+
 	if (!retval_range_within(range, reg)) {
 		verbose_invalid_scalar(env, reg, range, exit_ctx, reg_name);
 		if (!is_subprog &&