59 lines
2.0 KiB
Diff
59 lines
2.0 KiB
Diff
From: Sven Eckelmann <sven@narfation.org>
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Date: Sun, 12 Feb 2017 11:26:33 +0100
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Subject: batman-adv: Fix double free during fragment merge error
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The function batadv_frag_skb_buffer was supposed not to consume the skbuff
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on errors. This was followed in the helper function
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batadv_frag_insert_packet when the skb would potentially be inserted in the
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fragment queue. But it could happen that the next helper function
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batadv_frag_merge_packets would try to merge the fragments and fail. This
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results in a kfree_skb of all the enqueued fragments (including the just
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inserted one). batadv_recv_frag_packet would detect the error in
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batadv_frag_skb_buffer and try to free the skb again.
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The behavior of batadv_frag_skb_buffer (and its helper
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batadv_frag_insert_packet) must therefore be changed to always consume the
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skbuff to have a common behavior and avoid the double kfree_skb.
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Fixes: 9b3eab61754d ("batman-adv: Receive fragmented packets and merge")
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Signed-off-by: Sven Eckelmann <sven@narfation.org>
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Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/e3bab02816097f860545d9ce9ae0808c69d7c92f
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diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
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index 0854ebd8613e9bf9044b04099b11341325d6e194..31e97e9aee0d543b68be091936888e1f6c9dd7eb 100644
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--- a/net/batman-adv/fragmentation.c
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+++ b/net/batman-adv/fragmentation.c
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@@ -239,8 +239,10 @@ err_unlock:
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spin_unlock_bh(&chain->lock);
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err:
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- if (!ret)
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+ if (!ret) {
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kfree(frag_entry_new);
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+ kfree_skb(skb);
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+ }
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return ret;
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}
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@@ -313,7 +315,7 @@ free:
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*
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* There are three possible outcomes: 1) Packet is merged: Return true and
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* set *skb to merged packet; 2) Packet is buffered: Return true and set *skb
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- * to NULL; 3) Error: Return false and leave skb as is.
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+ * to NULL; 3) Error: Return false and free skb.
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*
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* Return: true when packet is merged or buffered, false when skb is not not
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* used.
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@@ -338,9 +340,9 @@ bool batadv_frag_skb_buffer(struct sk_buff **skb,
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goto out_err;
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out:
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- *skb = skb_out;
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ret = true;
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out_err:
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+ *skb = skb_out;
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return ret;
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}
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