netdev - [bpf-next PATCH v2 3/7] bpf: verifier, refine 32bit bound in do_refine_retval

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <158560421952.10843.12496354931526965046.stgit@john-Precision-5820-Tower>
Date:   Mon, 30 Mar 2020 14:36:59 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     ecree@...arflare.com, yhs@...com, alexei.starovoitov@...il.com,
        daniel@...earbox.net
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        john.fastabend@...il.com
Subject: [bpf-next PATCH v2 3/7] bpf: verifier,
 refine 32bit bound in do_refine_retval_range

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@...il.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);