From: John Fastabend <john.fastabend@gmail.com>
To: ecree@solarflare.com, yhs@fb.com, alexei.starovoitov@gmail.com,
daniel@iogearbox.net
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, john.fastabend@gmail.com
Subject: [bpf-next PATCH v2 3/7] bpf: verifier, refine 32bit bound in do_refine_retval_range
Date: Mon, 30 Mar 2020 14:36:59 -0700 [thread overview]
Message-ID: <158560421952.10843.12496354931526965046.stgit@john-Precision-5820-Tower> (raw)
In-Reply-To: <158560409224.10843.3588655801186916301.stgit@john-Precision-5820-Tower>
Further refine return values range in do_refine_retval_range by noting
these are int return types (We will assume here that int is a 32-bit type).
Two reasons to pull this out of original patch. First it makes the original
fix impossible to backport. And second I've not seen this as being problematic
in practice unlike the other case.
Fixes: 849fa50662fbc ("bpf/verifier: refine retval R0 state for bpf_get_stack helper")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
kernel/bpf/verifier.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 804a39a..cddae95 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4335,6 +4335,7 @@ static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
return;
ret_reg->smax_value = meta->msize_max_value;
+ ret_reg->s32_max_value = meta->msize_max_value;
__reg_deduce_bounds(ret_reg);
__reg_bound_offset(ret_reg);
__update_reg_bounds(ret_reg);
next prev parent reply other threads:[~2020-03-30 21:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 21:35 [bpf-next PATCH v2 0/7] ALU32 bounds tracking support John Fastabend
2020-03-30 21:36 ` [bpf-next PATCH v2 1/7] bpf: verifier, do_refine_retval_range may clamp umin to 0 incorrectly John Fastabend
2020-03-30 21:36 ` [bpf-next PATCH v2 2/7] bpf: verifier, do explicit ALU32 bounds tracking John Fastabend
2020-03-30 22:23 ` Alexei Starovoitov
2020-03-30 21:36 ` John Fastabend [this message]
2020-03-30 21:37 ` [bpf-next PATCH v2 4/7] bpf: test_progs, add test to catch retval refine error handling John Fastabend
2020-03-30 21:37 ` [bpf-next PATCH v2 5/7] bpf: test_verifier, bpf_get_stack return value add <0 John Fastabend
2020-03-30 21:38 ` [bpf-next PATCH v2 6/7] bpf: test_verifier, #65 error message updates for trunc of boundary-cross John Fastabend
2020-03-30 21:38 ` [bpf-next PATCH v2 7/7] bpf: test_verifier, add alu32 bounds tracking tests John Fastabend
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