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authorJiri Benc <jbenc@redhat.com>2015-03-29 16:05:28 +0200
committerDavid S. Miller <davem@davemloft.net>2015-03-31 14:07:24 -0400
commit5899f0478528b59ea9ced201eacb3e56ca406c39 (patch)
treeb260bb0d9c9089954268ba60a625f0d995334060
parentf5e2dc5d7fe78fe4d8748d217338f4f7b6a5d7ea (diff)
downloadlinux-5899f0478528b59ea9ced201eacb3e56ca406c39.tar.bz2
netlink: pad nla_memcpy dest buffer with zeroes
This is especially important in cases where the kernel allocs a new structure and expects a field to be set from a netlink attribute. If such attribute is shorter than expected, the rest of the field is left containing previous data. When such field is read back by the user space, kernel memory content is leaked. Signed-off-by: Jiri Benc <jbenc@redhat.com> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--lib/nlattr.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 76a1b59523ab..f5907d23272d 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -279,6 +279,8 @@ int nla_memcpy(void *dest, const struct nlattr *src, int count)
int minlen = min_t(int, count, nla_len(src));
memcpy(dest, nla_data(src), minlen);
+ if (count > minlen)
+ memset(dest + minlen, 0, count - minlen);
return minlen;
}