net, decnet: convert dn_fib_info.fib_clntref 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: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Reshetova, Elena 2017-07-04 15:53:00 +03:00 committed by David S. Miller
parent 66af846fe5
commit e0542dd518
2 changed files with 6 additions and 5 deletions

View File

@ -2,6 +2,7 @@
#define _NET_DN_FIB_H
#include <linux/netlink.h>
#include <linux/refcount.h>
extern const struct nla_policy rtm_dn_policy[];
@ -28,7 +29,7 @@ struct dn_fib_info {
struct dn_fib_info *fib_next;
struct dn_fib_info *fib_prev;
int fib_treeref;
atomic_t fib_clntref;
refcount_t fib_clntref;
int fib_dead;
unsigned int fib_flags;
int fib_protocol;
@ -130,7 +131,7 @@ void dn_fib_free_info(struct dn_fib_info *fi);
static inline void dn_fib_info_put(struct dn_fib_info *fi)
{
if (atomic_dec_and_test(&fi->fib_clntref))
if (refcount_dec_and_test(&fi->fib_clntref))
dn_fib_free_info(fi);
}

View File

@ -389,7 +389,7 @@ link_it:
}
fi->fib_treeref++;
atomic_inc(&fi->fib_clntref);
refcount_set(&fi->fib_clntref, 1);
spin_lock(&dn_fib_info_lock);
fi->fib_next = dn_fib_info_list;
fi->fib_prev = NULL;
@ -425,7 +425,7 @@ int dn_fib_semantic_match(int type, struct dn_fib_info *fi, const struct flowidn
switch (type) {
case RTN_NAT:
DN_FIB_RES_RESET(*res);
atomic_inc(&fi->fib_clntref);
refcount_inc(&fi->fib_clntref);
return 0;
case RTN_UNICAST:
case RTN_LOCAL:
@ -438,7 +438,7 @@ int dn_fib_semantic_match(int type, struct dn_fib_info *fi, const struct flowidn
}
if (nhsel < fi->fib_nhs) {
res->nh_sel = nhsel;
atomic_inc(&fi->fib_clntref);
refcount_inc(&fi->fib_clntref);
return 0;
}
endfor_nexthops(fi);