50 lines
1.7 KiB
Diff
50 lines
1.7 KiB
Diff
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From 387193faf4e8216ef201f2c685f69f6fa766ec46 Mon Sep 17 00:00:00 2001
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From: Florian Westphal <fw@strlen.de>
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Date: Sun, 18 Mar 2018 19:33:27 +0100
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Subject: [PATCH] libmnl: zero attribute padding
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Sergei Trofimovich reports 'uninitialized bytes' warnings from nftables:
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Syscall param sendmsg(msg.msg_iov[0]) points to uninitialised byte(s)
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at 0x55B9EFB: sendmsg (in /lib64/libc-2.25.so)
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by 0x43E658: mnl_nft_socket_sendmsg (mnl.c:239)
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by 0x43E658: mnl_batch_talk (mnl.c:254)
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by 0x407898: nft_netlink (libnftables.c:58)
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by 0x407898: nft_run (libnftables.c:96)
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by 0x407CD5: nft_run_cmd_from_buffer (libnftables.c:291)
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by 0x406EDE: main (main.c:274)
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This is harmless, the uninitialized memory is the padding
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that sometimes needs to be inserted between end of an attribute
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and the beginning of the new attribute.
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Zero it to silence memory sanitizer output.
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Signed-off-by: Florian Westphal <fw@strlen.de>
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Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
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(cherry picked from commit 37c876b55a2c00424ccda5a300ab5fdec1d88b22)
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---
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src/attr.c | 5 +++++
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1 file changed, 5 insertions(+)
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diff --git a/src/attr.c b/src/attr.c
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index 4f131874c11e4..0359ba959d7a0 100644
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--- a/src/attr.c
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+++ b/src/attr.c
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@@ -412,10 +412,15 @@ void mnl_attr_put(struct nlmsghdr *nlh, uint16_t type, size_t len,
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{
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struct nlattr *attr = mnl_nlmsg_get_payload_tail(nlh);
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uint16_t payload_len = MNL_ALIGN(sizeof(struct nlattr)) + len;
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+ int pad;
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attr->nla_type = type;
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attr->nla_len = payload_len;
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memcpy(mnl_attr_get_payload(attr), data, len);
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+ pad = MNL_ALIGN(len) - len;
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+ if (pad > 0)
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+ memset(mnl_attr_get_payload(attr) + len, 0, pad);
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+
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nlh->nlmsg_len += MNL_ALIGN(payload_len);
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}
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