diff mbox series

[PATHC,bpf,v5,1/3] skmsg: lose offset info in sk_psock_skb_ingress

Message ID 20211012065705.224643-1-liujian56@huawei.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series [PATHC,bpf,v5,1/3] skmsg: lose offset info in sk_psock_skb_ingress | expand

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Context Check Description
netdev/cover_letter warning Series does not have a cover letter
netdev/fixes_present success Fixes tag present in non-next series
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for bpf
netdev/subject_prefix success Link
netdev/cc_maintainers success CCed 14 of 14 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 67 this patch: 67
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Fixes tag looks correct
netdev/checkpatch warning CHECK: Prefer using the BIT macro WARNING: line length of 81 exceeds 80 columns
netdev/build_allmodconfig_warn success Errors and warnings before: 67 this patch: 67
netdev/header_inline success No static functions without inline keyword in header files
bpf/vmtest-bpf-PR pending PR summary
bpf/vmtest-bpf pending VM_Test

Commit Message

Liu Jian Oct. 12, 2021, 6:57 a.m. UTC 
If sockmap enable strparser, there are lose offset info in
sk_psock_skb_ingress. If the length determined by parse_msg function
is not skb->len, the skb will be converted to sk_msg multiple times,
and userspace app will get the data multiple times.

Fix this by get the offset and length from strp_msg.
And as Cong suggestion, add one bit in skb->_sk_redir to distinguish
enable or disable strparser.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
---
v1->v2: fix build error when disable CONFIG_BPF_STREAM_PARSER
v2->v3: Add one bit in skb->_sk_redir to distinguish enable or disable strparser
v3->v4: Remove "#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)" code;
	and let "stm" have a more precise scope.
v4->v5: Add fix tag.
 include/linux/skmsg.h | 18 ++++++++++++++++--
 net/core/skmsg.c      | 40 ++++++++++++++++++++++++++++++----------
 2 files changed, 46 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14ab0c0bc924..94e2a1f6e58d 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -508,8 +508,22 @@  static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
 
 #if IS_ENABLED(CONFIG_NET_SOCK_MSG)
 
-/* We only have one bit so far. */
-#define BPF_F_PTR_MASK ~(BPF_F_INGRESS)
+#define BPF_F_STRPARSER	(1UL << 1)
+
+/* We only have two bits so far. */
+#define BPF_F_PTR_MASK ~(BPF_F_INGRESS | BPF_F_STRPARSER)
+
+static inline bool skb_bpf_strparser(const struct sk_buff *skb)
+{
+	unsigned long sk_redir = skb->_sk_redir;
+
+	return sk_redir & BPF_F_STRPARSER;
+}
+
+static inline void skb_bpf_set_strparser(struct sk_buff *skb)
+{
+	skb->_sk_redir |= BPF_F_STRPARSER;
+}
 
 static inline bool skb_bpf_ingress(const struct sk_buff *skb)
 {
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 2d6249b28928..e85b7f8491b9 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -494,6 +494,7 @@  static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
 }
 
 static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
+					u32 off, u32 len,
 					struct sk_psock *psock,
 					struct sock *sk,
 					struct sk_msg *msg)
@@ -507,11 +508,11 @@  static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
 	 */
 	if (skb_linearize(skb))
 		return -EAGAIN;
-	num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
+	num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
 	if (unlikely(num_sge < 0))
 		return num_sge;
 
-	copied = skb->len;
+	copied = len;
 	msg->sg.start = 0;
 	msg->sg.size = copied;
 	msg->sg.end = num_sge;
@@ -522,9 +523,11 @@  static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
 	return copied;
 }
 
-static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb);
+static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
+				     u32 off, u32 len);
 
-static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
+static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb,
+				u32 off, u32 len)
 {
 	struct sock *sk = psock->sk;
 	struct sk_msg *msg;
@@ -535,7 +538,7 @@  static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 	 * correctly.
 	 */
 	if (unlikely(skb->sk == sk))
-		return sk_psock_skb_ingress_self(psock, skb);
+		return sk_psock_skb_ingress_self(psock, skb, off, len);
 	msg = sk_psock_create_ingress_msg(sk, skb);
 	if (!msg)
 		return -EAGAIN;
@@ -547,7 +550,7 @@  static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 	 * into user buffers.
 	 */
 	skb_set_owner_r(skb, sk);
-	err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
+	err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
 	if (err < 0)
 		kfree(msg);
 	return err;
@@ -557,7 +560,8 @@  static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
  * skb. In this case we do not need to check memory limits or skb_set_owner_r
  * because the skb is already accounted for here.
  */
-static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb)
+static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
+				     u32 off, u32 len)
 {
 	struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
 	struct sock *sk = psock->sk;
@@ -567,7 +571,7 @@  static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb
 		return -EAGAIN;
 	sk_msg_init(msg);
 	skb_set_owner_r(skb, sk);
-	err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
+	err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
 	if (err < 0)
 		kfree(msg);
 	return err;
@@ -581,7 +585,7 @@  static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
 			return -EAGAIN;
 		return skb_send_sock(psock->sk, skb, off, len);
 	}
-	return sk_psock_skb_ingress(psock, skb);
+	return sk_psock_skb_ingress(psock, skb, off, len);
 }
 
 static void sk_psock_skb_state(struct sk_psock *psock,
@@ -624,6 +628,12 @@  static void sk_psock_backlog(struct work_struct *work)
 	while ((skb = skb_dequeue(&psock->ingress_skb))) {
 		len = skb->len;
 		off = 0;
+		if (skb_bpf_strparser(skb)) {
+			struct strp_msg *stm = strp_msg(skb);
+
+			off = stm->offset;
+			len = stm->full_len;
+		}
 start:
 		ingress = skb_bpf_ingress(skb);
 		skb_bpf_redirect_clear(skb);
@@ -930,6 +940,7 @@  static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
 {
 	struct sock *sk_other;
 	int err = 0;
+	u32 len, off;
 
 	switch (verdict) {
 	case __SK_PASS:
@@ -949,7 +960,15 @@  static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
 		 * retrying later from workqueue.
 		 */
 		if (skb_queue_empty(&psock->ingress_skb)) {
-			err = sk_psock_skb_ingress_self(psock, skb);
+			len = skb->len;
+			off = 0;
+			if (skb_bpf_strparser(skb)) {
+				struct strp_msg *stm = strp_msg(skb);
+
+				off = stm->offset;
+				len = stm->full_len;
+			}
+			err = sk_psock_skb_ingress_self(psock, skb, off, len);
 		}
 		if (err < 0) {
 			spin_lock_bh(&psock->ingress_lock);
@@ -1018,6 +1037,7 @@  static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
 		ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 		skb->sk = NULL;
 	}
+	skb_bpf_set_strparser(skb);
 	sk_psock_verdict_apply(psock, skb, ret);
 out:
 	rcu_read_unlock();