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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
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5
include/net/dn_fib.h
View File

@ -2,6 +2,7 @@
#define _NET_DN_FIB_H #define _NET_DN_FIB_H
#include <linux/netlink.h> #include <linux/netlink.h>
#include <linux/refcount.h>
extern const struct nla_policy rtm_dn_policy[]; 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_next;
struct dn_fib_info *fib_prev; struct dn_fib_info *fib_prev;
int fib_treeref; int fib_treeref;
atomic_t fib_clntref; refcount_t fib_clntref;
int fib_dead; int fib_dead;
unsigned int fib_flags; unsigned int fib_flags;
int fib_protocol; 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) 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); dn_fib_free_info(fi);
} }

6
net/decnet/dn_fib.c
View File

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