4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Benedict Wong <benedictwong@xxxxxxxxxx> commit e2612cd496e7b465711d219ea6118893d7253f52 upstream. Fixes 9b42c1f179a6, which changed the default route lookup behavior for tunnel mode SAs in the outbound direction to use the skb mark, whereas previously mark=0 was used if the output mark was unspecified. In mark-based routing schemes such as Android’s, this change in default behavior causes routing loops or lookup failures. This patch restores the default behavior of using a 0 mark while still incorporating the skb mark if the SET_MARK (and SET_MARK_MASK) is specified. Tested with additions to Android's kernel unit test suite: https://android-review.googlesource.com/c/kernel/tests/+/860150 Fixes: 9b42c1f179a6 ("xfrm: Extend the output_mark to support input direction and masking") Signed-off-by: Benedict Wong <benedictwong@xxxxxxxxxx> Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/xfrm/xfrm_policy.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1628,7 +1628,10 @@ static struct dst_entry *xfrm_bundle_cre dst_copy_metrics(dst1, dst); if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) { - __u32 mark = xfrm_smark_get(fl->flowi_mark, xfrm[i]); + __u32 mark = 0; + + if (xfrm[i]->props.smark.v || xfrm[i]->props.smark.m) + mark = xfrm_smark_get(fl->flowi_mark, xfrm[i]); family = xfrm[i]->props.family; dst = xfrm_dst_lookup(xfrm[i], tos, fl->flowi_oif,
