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* [PATCH AUTOSEL 4.9 03/33] netfilter: ebtables: fix a memory leak bug in compat
       [not found] <20190814022323.17111-1-sashal@kernel.org>
@ 2019-08-14  2:22 ` Sasha Levin
  0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2019-08-14  2:22 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Wenwen Wang, Florian Westphal, Pablo Neira Ayuso, Sasha Levin,
	netfilter-devel, coreteam, netdev

From: Wenwen Wang <wenwen@cs.uga.edu>

[ Upstream commit 15a78ba1844a8e052c1226f930133de4cef4e7ad ]

In compat_do_replace(), a temporary buffer is allocated through vmalloc()
to hold entries copied from the user space. The buffer address is firstly
saved to 'newinfo->entries', and later on assigned to 'entries_tmp'. Then
the entries in this temporary buffer is copied to the internal kernel
structure through compat_copy_entries(). If this copy process fails,
compat_do_replace() should be terminated. However, the allocated temporary
buffer is not freed on this path, leading to a memory leak.

To fix the bug, free the buffer before returning from compat_do_replace().

Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bridge/netfilter/ebtables.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 142ccaae9c7b6..4a47918b504f8 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -2288,8 +2288,10 @@ static int compat_do_replace(struct net *net, void __user *user,
 	state.buf_kern_len = size64;
 
 	ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
-	if (WARN_ON(ret < 0))
+	if (WARN_ON(ret < 0)) {
+		vfree(entries_tmp);
 		goto out_unlock;
+	}
 
 	vfree(entries_tmp);
 	tmp.entries_size = size64;
-- 
2.20.1


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2019-08-14  2:22 ` [PATCH AUTOSEL 4.9 03/33] netfilter: ebtables: fix a memory leak bug in compat Sasha Levin

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