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[FIB]: full_children & empty_children should be uint, not ushort 

If declared as unsigned short, these fields can overflow, and whole
trie logic is broken. I could not make the machine crash, but some
tnode can never be freed.

Note for 64 bit arches : By reordering t_key and parent in [node,
leaf, tnode] structures, we can use 32 bits hole after t_key so that
sizeof(struct tnode) doesnt change after this patch.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2008-01-13 22:31:44 -08:00 committed by David S. Miller
parent f16f3026db
commit 8d96544475
1 changed files with 12 additions and 13 deletions
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25
net/ipv4/fib_trie.c
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@ -97,13 +97,13 @@ typedef unsigned int t_key;
#define IS_LEAF(n) (n->parent & T_LEAF)
struct node {
t_key key;
unsigned long parent;
t_key key;
};
struct leaf {
t_key key;
unsigned long parent;
t_key key;
struct hlist_head list;
struct rcu_head rcu;
};
@ -116,12 +116,12 @@ struct leaf_info {
};
struct tnode {
t_key key;
unsigned long parent;
t_key key;
unsigned char pos; /* 2log(KEYLENGTH) bits needed */
unsigned char bits; /* 2log(KEYLENGTH) bits needed */
unsigned short full_children; /* KEYLENGTH bits needed */
unsigned short empty_children; /* KEYLENGTH bits needed */
unsigned int full_children; /* KEYLENGTH bits needed */
unsigned int empty_children; /* KEYLENGTH bits needed */
struct rcu_head rcu;
struct node *child[0];
};
@ -329,12 +329,12 @@ static inline void free_leaf_info(struct leaf_info *leaf)
call_rcu(&leaf->rcu, __leaf_info_free_rcu);
}
static struct tnode *tnode_alloc(unsigned int size)
static struct tnode *tnode_alloc(size_t size)
{
struct page *pages;
if (size <= PAGE_SIZE)
return kcalloc(size, 1, GFP_KERNEL);
return kzalloc(size, GFP_KERNEL);
pages = alloc_pages(GFP_KERNEL|__GFP_ZERO, get_order(size));
if (!pages)
@ -346,8 +346,8 @@ static struct tnode *tnode_alloc(unsigned int size)
static void __tnode_free_rcu(struct rcu_head *head)
{
struct tnode *tn = container_of(head, struct tnode, rcu);
unsigned int size = sizeof(struct tnode) +
(1 << tn->bits) * sizeof(struct node *);
size_t size = sizeof(struct tnode) +
(sizeof(struct node *) << tn->bits);
if (size <= PAGE_SIZE)
kfree(tn);
@ -386,8 +386,7 @@ static struct leaf_info *leaf_info_new(int plen)
static struct tnode* tnode_new(t_key key, int pos, int bits)
{
int nchildren = 1<<bits;
int sz = sizeof(struct tnode) + nchildren * sizeof(struct node *);
size_t sz = sizeof(struct tnode) + (sizeof(struct node *) << bits);
struct tnode *tn = tnode_alloc(sz);
if (tn) {
@ -399,8 +398,8 @@ static struct tnode* tnode_new(t_key key, int pos, int bits)
tn->empty_children = 1<<bits;
}
pr_debug("AT %p s=%u %u\n", tn, (unsigned int) sizeof(struct tnode),
(unsigned int) (sizeof(struct node) * 1<<bits));
pr_debug("AT %p s=%u %lu\n", tn, (unsigned int) sizeof(struct tnode),
(unsigned long) (sizeof(struct node) << bits));
return tn;
}