From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: linux-bluetooth@vger.kernel.org
Subject: [PATCH v2 01/15] skbuff: introduce skb_pull_data
Date: Wed, 1 Dec 2021 10:54:52 -0800 [thread overview]
Message-ID: <20211201185506.1421186-2-luiz.dentz@gmail.com> (raw)
In-Reply-To: <20211201185506.1421186-1-luiz.dentz@gmail.com>
From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Like skb_pull but returns the original data pointer before pulling the
data after performing a check against sbk->len.
This allows to change code that does "struct foo *p = (void *)skb->data;"
which is hard to audit and error prone, to:
p = skb_pull_data(skb, sizeof(*p));
if (!p)
return;
Which is both safer and cleaner.
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
include/linux/skbuff.h | 2 ++
net/core/skbuff.c | 23 +++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index eba256af64a5..877dda38684a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2373,6 +2373,8 @@ static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len)
return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
}
+void *skb_pull_data(struct sk_buff *skb, size_t len);
+
void *__pskb_pull_tail(struct sk_buff *skb, int delta);
static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a33247fdb8f5..0b19833ffbce 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2023,6 +2023,29 @@ void *skb_pull(struct sk_buff *skb, unsigned int len)
}
EXPORT_SYMBOL(skb_pull);
+/**
+ * skb_pull_data - remove data from the start of a buffer returning its
+ * original position.
+ * @skb: buffer to use
+ * @len: amount of data to remove
+ *
+ * This function removes data from the start of a buffer, returning
+ * the memory to the headroom. A pointer to the original data in the buffer
+ * is returned after checking if there is enough data to pull. Once the
+ * data has been pulled future pushes will overwrite the old data.
+ */
+void *skb_pull_data(struct sk_buff *skb, size_t len)
+{
+ void *data = skb->data;
+
+ if (skb->len < len)
+ return NULL;
+
+ skb_pull(skb, len);
+
+ return data;
+}
+
/**
* skb_trim - remove end from a buffer
* @skb: buffer to alter
--
2.33.1
next prev parent reply other threads:[~2021-12-01 18:55 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-01 18:54 [PATCH v2 00/15] Rework parsing of HCI events Luiz Augusto von Dentz
2021-12-01 18:54 ` Luiz Augusto von Dentz [this message]
2021-12-01 18:54 ` [PATCH v2 02/15] Bluetooth: HCI: Use skb_pull_data to parse BR/EDR events Luiz Augusto von Dentz
2021-12-01 18:54 ` [PATCH v2 03/15] Bluetooth: HCI: Use skb_pull_data to parse Command Complete event Luiz Augusto von Dentz
2021-12-01 18:54 ` [PATCH v2 04/15] Bluetooth: HCI: Use skb_pull_data to parse Number of Complete Packets event Luiz Augusto von Dentz
2021-12-01 18:54 ` [PATCH v2 05/15] Bluetooth: HCI: Use skb_pull_data to parse Inquiry Result event Luiz Augusto von Dentz
2021-12-01 18:54 ` [PATCH v2 06/15] Bluetooth: HCI: Use skb_pull_data to parse Inquiry Result with RSSI event Luiz Augusto von Dentz
2021-12-01 18:54 ` [PATCH v2 07/15] Bluetooth: HCI: Use skb_pull_data to parse Extended Inquiry Result event Luiz Augusto von Dentz
2021-12-01 18:54 ` [PATCH v2 08/15] Bluetooth: HCI: Use skb_pull_data to parse LE Metaevents Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 09/15] Bluetooth: HCI: Use skb_pull_data to parse LE Advertising Report event Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 10/15] Bluetooth: HCI: Use skb_pull_data to parse LE Ext " Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 11/15] Bluetooth: HCI: Use skb_pull_data to parse LE Direct " Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 12/15] Bluetooth: hci_event: Use of a function table to handle HCI events Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 13/15] Bluetooth: hci_event: Use of a function table to handle LE subevents Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 14/15] Bluetooth: hci_event: Use of a function table to handle Command Complete Luiz Augusto von Dentz
2021-12-01 18:55 ` [PATCH v2 15/15] Bluetooth: hci_event: Use of a function table to handle Command Status Luiz Augusto von Dentz
2021-12-03 21:12 ` [PATCH v2 00/15] Rework parsing of HCI events Marcel Holtmann
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