From 67378563df2e168d32a4054616f244a91aec462d Mon Sep 17 00:00:00 2001
From: David Ward <david.ward@ll.mit.edu>
Date: Tue, 27 Mar 2012 09:01:52 +0000
Subject: net/garp: avoid infinite loop if attribute already exists
An infinite loop occurred if garp_attr_create was called with the values
of an existing attribute. This might happen if a previous leave request
for the attribute has not yet been followed by a PDU transmission (or,
if the application previously issued a join request for the attribute
and is now issuing another one, without having issued a leave request).
If garp_attr_create finds an existing attribute having the same values,
return the address to it. Its state will then get updated (i.e., if it
was in a leaving state, it will move into a non-leaving state and not
get deleted during the next PDU transmission).
To accomplish this fix, collapse garp_attr_insert into garp_attr_create
(which is its only caller).
Thanks to Jorge Boncompte [DTI2] <jorge@dti2.net> for contributing to
this fix.
Signed-off-by: David Ward <david.ward@ll.mit.edu>
Acked-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/802/garp.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
(limited to 'net/802')
diff --git a/net/802/garp.c b/net/802/garp.c
index 8e21b6db3981..a5c224830439 100644
--- a/net/802/garp.c
+++ b/net/802/garp.c
@@ -167,7 +167,8 @@ static struct garp_attr *garp_attr_lookup(const struct garp_applicant *app,
return NULL;
}
-static void garp_attr_insert(struct garp_applicant *app, struct garp_attr *new)
+static struct garp_attr *garp_attr_create(struct garp_applicant *app,
+ const void *data, u8 len, u8 type)
{
struct rb_node *parent = NULL, **p = &app->gid.rb_node;
struct garp_attr *attr;
@@ -176,21 +177,16 @@ static void garp_attr_insert(struct garp_applicant *app, struct garp_attr *new)
while (*p) {
parent = *p;
attr = rb_entry(parent, struct garp_attr, node);
- d = garp_attr_cmp(attr, new->data, new->dlen, new->type);
+ d = garp_attr_cmp(attr, data, len, type);
if (d < 0)
p = &parent->rb_left;
else if (d > 0)
p = &parent->rb_right;
+ else {
+ /* The attribute already exists; re-use it. */
+ return attr;
+ }
}
- rb_link_node(&new->node, parent, p);
- rb_insert_color(&new->node, &app->gid);
-}
-
-static struct garp_attr *garp_attr_create(struct garp_applicant *app,
- const void *data, u8 len, u8 type)
-{
- struct garp_attr *attr;
-
attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
if (!attr)
return attr;
@@ -198,7 +194,9 @@ static struct garp_attr *garp_attr_create(struct garp_applicant *app,
attr->type = type;
attr->dlen = len;
memcpy(attr->data, data, len);
- garp_attr_insert(app, attr);
+
+ rb_link_node(&attr->node, parent, p);
+ rb_insert_color(&attr->node, &app->gid);
return attr;
}
--
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