dlan17/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ipv4: convert dst_metrics.refcnt from atomic_t to refcount_t

Browse Source 
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2017-08-18 12:08:07 -07:00
committed by David S. Miller
parent 633cefe390
commit 9620fef27e
4 changed files with 9 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/core/dst.c
+3 -3
View File
@@ -55,7 +55,7 @@ const struct dst_metrics dst_default_metrics = {
* We really want to avoid false sharing on this variable, and catch
* any writes on it.
*/
.refcnt = ATOMIC_INIT(1),
.refcnt = REFCOUNT_INIT(1),
};
void dst_init(struct dst_entry *dst, struct dst_ops *ops,
@@ -213,7 +213,7 @@ u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
unsigned long prev, new;
atomic_set(&p->refcnt, 1);
refcount_set(&p->refcnt, 1);
memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
new = (unsigned long) p;
@@ -225,7 +225,7 @@ u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
if (prev & DST_METRICS_READ_ONLY)
p = NULL;
} else if (prev & DST_METRICS_REFCOUNTED) {
if (atomic_dec_and_test(&old_p->refcnt))
if (refcount_dec_and_test(&old_p->refcnt))
kfree(old_p);
}
}