Re: call panic if nl_table allocation fails

[David Miller]

From: Akinobu Mita [EMAIL PROTECTED]
Date: Wed, 23 Aug 2006 20:37:40 +0900

 This patch makes crash happen if initialization of nl_table fails
 in initcalls. It is better than getting use after free crash later.
 
 Cc: Patrick McHardy [EMAIL PROTECTED]
 Cc: David Miller [EMAIL PROTECTED]
 Signed-off-by: Akinobu Mita [EMAIL PROTECTED]

Patch applied, thank you.
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call panic if nl_table allocation fails

[Akinobu Mita]

This patch makes crash happen if initialization of nl_table fails
in initcalls. It is better than getting use after free crash later.

Cc: Patrick McHardy [EMAIL PROTECTED]
Cc: David Miller [EMAIL PROTECTED]
Signed-off-by: Akinobu Mita [EMAIL PROTECTED]

Index: work-failmalloc/net/netlink/af_netlink.c
===
--- work-failmalloc.orig/net/netlink/af_netlink.c
+++ work-failmalloc/net/netlink/af_netlink.c
@@ -1273,8 +1273,7 @@ netlink_kernel_create(int unit, unsigned
struct netlink_sock *nlk;
unsigned long *listeners = NULL;
 
-   if (!nl_table)
-   return NULL;
+   BUG_ON(!nl_table);
 
if (unit0 || unit=MAX_LINKS)
return NULL;
@@ -1745,11 +1744,8 @@ static int __init netlink_proto_init(voi
netlink_skb_parms_too_large();
 
nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
-   if (!nl_table) {
-enomem:
-   printk(KERN_CRIT netlink_init: Cannot allocate nl_table\n);
-   return -ENOMEM;
-   }
+   if (!nl_table)
+   goto panic;
 
if (num_physpages = (128 * 1024))
max = num_physpages  (21 - PAGE_SHIFT);
@@ -1769,7 +1765,7 @@ enomem:
nl_pid_hash_free(nl_table[i].hash.table,
 1 * sizeof(*hash-table));
kfree(nl_table);
-   goto enomem;
+   goto panic;
}
memset(hash-table, 0, 1 * sizeof(*hash-table));
hash-max_shift = order;
@@ -1786,6 +1782,8 @@ enomem:
rtnetlink_init();
 out:
return err;
+panic:
+   panic(netlink_init: Cannot allocate nl_table\n);
 }
 
 core_initcall(netlink_proto_init);
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Re: call panic if nl_table allocation fails

[James Morris]

On Wed, 23 Aug 2006, Akinobu Mita wrote:

 This patch makes crash happen if initialization of nl_table fails
 in initcalls. It is better than getting use after free crash later.

   nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);

Perhaps it'd be better to declare this as an array rather than allocating 
it at runtime.



- James
-- 
James Morris
[EMAIL PROTECTED]
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Re: call panic if nl_table allocation fails

[Patrick McHardy]

James Morris wrote:
 On Wed, 23 Aug 2006, Akinobu Mita wrote:
 
 
This patch makes crash happen if initialization of nl_table fails
in initcalls. It is better than getting use after free crash later.
 
 
  nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
 
 
 Perhaps it'd be better to declare this as an array rather than allocating 
 it at runtime.

That would still leave the MAX_LINKS allocations for the pid hashes
which need to be allocated because they are dynamically sized. We
could delay the pid hash allocations until the first bind happens
of course, but I doubt it would be worth it since they start with
just a single bucket.

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