netdev - [PATCH net 2/2] bpf: sockmap, updating the sg structure should also update curr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20231206232706.374377-3-john.fastabend@gmail.com>
Date: Wed,  6 Dec 2023 15:27:06 -0800
From: John Fastabend <john.fastabend@...il.com>
To: kuba@...nel.org,
	jannh@...gle.com,
	daniel@...earbox.net
Cc: john.fastabend@...il.com,
	borisp@...dia.com,
	bpf@...r.kernel.org,
	netdev@...r.kernel.org
Subject: [PATCH net 2/2] bpf: sockmap, updating the sg structure should also update curr

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@...il.com>
---
 net/core/filter.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 7e4d7c3bcc84..1737884be52f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2602,6 +2602,22 @@ 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,
@@ -2721,6 +2737,7 @@ 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;
@@ -2857,6 +2874,7 @@ 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;
 }
@@ -3025,6 +3043,7 @@ 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;
 }
-- 
2.33.0