6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: John Fastabend <john.fastabend@xxxxxxxxx>
[ Upstream commit bb9aefde5bbaf6c168c77ba635c155b4980c2287 ]
Curr pointer should be updated when the sg structure is shifted.
Fixes: 7246d8ed4dcce ("bpf: helper to pop data from messages")
Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
Link: https://lore.kernel.org/r/20231206232706.374377-3-john.fastabend@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/core/filter.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/net/core/filter.c b/net/core/filter.c
index b149a165c405c..90fe3e7543833 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2591,6 +2591,22 @@ BPF_CALL_2(bpf_msg_cork_bytes, struct sk_msg *, msg, u32, bytes)
return 0;
}
+static void sk_msg_reset_curr(struct sk_msg *msg)
+{
+ u32 i = msg->sg.start;
+ u32 len = 0;
+
+ do {
+ len += sk_msg_elem(msg, i)->length;
+ sk_msg_iter_var_next(i);
+ if (len >= msg->sg.size)
+ break;
+ } while (i != msg->sg.end);
+
+ msg->sg.curr = i;
+ msg->sg.copybreak = 0;
+}
+
static const struct bpf_func_proto bpf_msg_cork_bytes_proto = {
.func = bpf_msg_cork_bytes,
.gpl_only = false,
@@ -2710,6 +2726,7 @@ BPF_CALL_4(bpf_msg_pull_data, struct sk_msg *, msg, u32, start,
msg->sg.end - shift + NR_MSG_FRAG_IDS :
msg->sg.end - shift;
out:
+ sk_msg_reset_curr(msg);
msg->data = sg_virt(&msg->sg.data[first_sge]) + start - offset;
msg->data_end = msg->data + bytes;
return 0;
@@ -2846,6 +2863,7 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start,
msg->sg.data[new] = rsge;
}
+ sk_msg_reset_curr(msg);
sk_msg_compute_data_pointers(msg);
return 0;
}
@@ -3014,6 +3032,7 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start,
sk_mem_uncharge(msg->sk, len - pop);
msg->sg.size -= (len - pop);
+ sk_msg_reset_curr(msg);
sk_msg_compute_data_pointers(msg);
return 0;
}
--
2.42.0
