| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.5 031/124] ax25: add link layer header validation function | Date | Mon, 18 Apr 2016 11:28:23 +0900 |
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4.5-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn <willemb@google.com>
[ Upstream commit ea47781c26510e5d97f80f9aceafe9065bd5e3aa ]
As variable length protocol, AX25 fails link layer header validation tests based on a minimum length. header_ops.validate allows protocols to validate headers that are shorter than hard_header_len. Implement this callback for AX25.
See also http://comments.gmane.org/gmane.linux.network/401064
Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ax25/ax25_ip.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
--- a/net/ax25/ax25_ip.c +++ b/net/ax25/ax25_ip.c @@ -228,8 +228,23 @@ netdev_tx_t ax25_ip_xmit(struct sk_buff } #endif +static bool ax25_validate_header(const char *header, unsigned int len) +{ + ax25_digi digi; + + if (!len) + return false; + + if (header[0]) + return true; + + return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL, + NULL); +} + const struct header_ops ax25_header_ops = { .create = ax25_hard_header, + .validate = ax25_validate_header, }; EXPORT_SYMBOL(ax25_header_ops);
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