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37 lines
1.3 KiB
37 lines
1.3 KiB
From c8f05589644d6b719e5a2c7fc548604f248be9be Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Sun, 29 Jul 2018 17:44:06 +0200
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Subject: [PATCH] nl: avoid NULL pointer dereference
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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It's a valid case to call nla_put() with NULL data and 0 len. It's done e.g. in
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the nla_put_attr().
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There has to be a check for data in nla_put() as passing NULL to the memcpy()
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is not allowed. Even if length is 0, both pointers have to be valid.
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For a reference see C99 standard (7.21.1/2), it says: "pointer arguments on
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such a call shall still have valid values".
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Reported-by: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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[christian.brauner@ubuntu.com: adapted commit message]
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Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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---
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src/lxc/nl.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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--- a/src/lxc/nl.c
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+++ b/src/lxc/nl.c
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@@ -61,7 +61,8 @@ static int nla_put(struct nlmsg *nlmsg,
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rta = NLMSG_TAIL(nlmsg->nlmsghdr);
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rta->rta_type = attr;
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rta->rta_len = rtalen;
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- memcpy(RTA_DATA(rta), data, len);
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+ if (data && len)
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+ memcpy(RTA_DATA(rta), data, len);
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nlmsg->nlmsghdr->nlmsg_len = tlen;
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return 0;
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}
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