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netfilter: ebtables: fix a memory leak bug in compat

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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>
This commit is contained in:
Wenwen Wang 2019-07-20 07:22:45 -05:00 committed by Pablo Neira Ayuso
parent 0cea0e1148
commit 15a78ba184
1 changed files with 3 additions and 1 deletions
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4
net/bridge/netfilter/ebtables.c
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@ -2261,8 +2261,10 @@ static int compat_do_replace(struct net *net, void __user *user,
state.buf_kern_len = size64; state.buf_kern_len = size64;
ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state); 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; goto out_unlock;
}
vfree(entries_tmp); vfree(entries_tmp);
tmp.entries_size = size64; tmp.entries_size = size64;