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authorEric Dumazet <edumazet@google.com>2017-08-18 12:08:07 -0700
committerDavid S. Miller <davem@davemloft.net>2017-08-18 15:14:07 -0700
commit9620fef27ed2cdb37bf6fd028f32bea2ef5119a8 (patch)
tree7d4b243d0f353b98fd379d0d6ad800d734506e30
parent633cefe390e59e9449dc88707235e57ac76b5c38 (diff)
downloadlinux-stericsson-9620fef27ed2cdb37bf6fd028f32bea2ef5119a8.tar.gz
ipv4: convert dst_metrics.refcnt from atomic_t to refcount_t
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>
-rw-r--r--include/net/dst.h3
-rw-r--r--net/core/dst.c6
-rw-r--r--net/ipv4/fib_semantics.c4
-rw-r--r--net/ipv4/route.c4
4 files changed, 9 insertions, 8 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
index f73611ec4017..93568bd0a352 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -14,6 +14,7 @@
#include <linux/rcupdate.h>
#include <linux/bug.h>
#include <linux/jiffies.h>
+#include <linux/refcount.h>
#include <net/neighbour.h>
#include <asm/processor.h>
@@ -107,7 +108,7 @@ struct dst_entry {
struct dst_metrics {
u32 metrics[RTAX_MAX];
- atomic_t refcnt;
+ refcount_t refcnt;
};
extern const struct dst_metrics dst_default_metrics;
diff --git a/net/core/dst.c b/net/core/dst.c
index 00aa972ad1a1..d6ead757c258 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -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);
}
}
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index d521caf57385..394d800db50c 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -220,7 +220,7 @@ static void free_fib_info_rcu(struct rcu_head *head)
} endfor_nexthops(fi);
m = fi->fib_metrics;
- if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
+ if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
kfree(m);
kfree(fi);
}
@@ -1090,7 +1090,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
kfree(fi);
return ERR_PTR(err);
}
- atomic_set(&fi->fib_metrics->refcnt, 1);
+ refcount_set(&fi->fib_metrics->refcnt, 1);
} else {
fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
}
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index d400c0543106..872b4cb136d3 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1398,7 +1398,7 @@ static void ipv4_dst_destroy(struct dst_entry *dst)
struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
struct rtable *rt = (struct rtable *) dst;
- if (p != &dst_default_metrics && atomic_dec_and_test(&p->refcnt))
+ if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
kfree(p);
if (!list_empty(&rt->rt_uncached)) {
@@ -1456,7 +1456,7 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
if (fi->fib_metrics != &dst_default_metrics) {
rt->dst._metrics |= DST_METRICS_REFCOUNTED;
- atomic_inc(&fi->fib_metrics->refcnt);
+ refcount_inc(&fi->fib_metrics->refcnt);
}
#ifdef CONFIG_IP_ROUTE_CLASSID
rt->dst.tclassid = nh->nh_tclassid;