From: Eric Dumazet <eduma...@google.com>
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 <eduma...@google.com>
---
include/net/dst.h | 2 +-
net/core/dst.c | 6 +++---
net/ipv4/fib_semantics.c | 2 +-
net/ipv4/route.c | 4 ++--
4 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/net/dst.h b/include/net/dst.h
index
f73611ec401754d4f52b5310a24da53566dafce6..dd38177c3a61f5c4e48be9d57d4d10d6b7d14672
100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -107,7 +107,7 @@ 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
00aa972ad1a1a451c24f3f8211243ad35c19433a..d6ead757c25895da01eb61bc9636c7e9b3cdfb3e
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
d521caf57385fa05f76036708057b95052330cb1..dd2ac3ed82ac86f8b417852233dfea69711e982d
100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -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
d400c05431063fc7bdd15b83ab540acc86decb3d..872b4cb136d3fa0cda403836cc83a156a65310a3
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;
