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net, ipv4: convert cipso_v4_doi.refcount from atomic_t to refcount_t

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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 09:35:01 +03:00 committed by David S. Miller
parent 87078f26b6
commit f6a6fede28
2 changed files with 8 additions and 7 deletions
include/net
cipso_ipv4.h
net/ipv4
cipso_ipv4.c

3
include/net/cipso_ipv4.h
View File

@ -41,6 +41,7 @@
#include <net/netlabel.h> #include <net/netlabel.h>
#include <net/request_sock.h> #include <net/request_sock.h>
#include <linux/atomic.h> #include <linux/atomic.h>
#include <linux/refcount.h>
#include <asm/unaligned.h> #include <asm/unaligned.h>
/* known doi values */ /* known doi values */
@ -85,7 +86,7 @@ struct cipso_v4_doi {
} map; } map;
u8 tags[CIPSO_V4_TAG_MAXCNT]; u8 tags[CIPSO_V4_TAG_MAXCNT];
atomic_t refcount; refcount_t refcount;
struct list_head list; struct list_head list;
struct rcu_head rcu; struct rcu_head rcu;
}; };

12
net/ipv4/cipso_ipv4.c
View File

@ -375,7 +375,7 @@ static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
struct cipso_v4_doi *iter; struct cipso_v4_doi *iter;
list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list) list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
if (iter->doi == doi && atomic_read(&iter->refcount)) if (iter->doi == doi && refcount_read(&iter->refcount))
return iter; return iter;
return NULL; return NULL;
} }
@ -429,7 +429,7 @@ int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
} }
} }
atomic_set(&doi_def->refcount, 1); refcount_set(&doi_def->refcount, 1);
spin_lock(&cipso_v4_doi_list_lock); spin_lock(&cipso_v4_doi_list_lock);
if (cipso_v4_doi_search(doi_def->doi)) { if (cipso_v4_doi_search(doi_def->doi)) {
@ -533,7 +533,7 @@ int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
ret_val = -ENOENT; ret_val = -ENOENT;
goto doi_remove_return; goto doi_remove_return;
} }
if (!atomic_dec_and_test(&doi_def->refcount)) { if (!refcount_dec_and_test(&doi_def->refcount)) {
spin_unlock(&cipso_v4_doi_list_lock); spin_unlock(&cipso_v4_doi_list_lock);
ret_val = -EBUSY; ret_val = -EBUSY;
goto doi_remove_return; goto doi_remove_return;
@ -576,7 +576,7 @@ struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
doi_def = cipso_v4_doi_search(doi); doi_def = cipso_v4_doi_search(doi);
if (!doi_def) if (!doi_def)
goto doi_getdef_return; goto doi_getdef_return;
if (!atomic_inc_not_zero(&doi_def->refcount)) if (!refcount_inc_not_zero(&doi_def->refcount))
doi_def = NULL; doi_def = NULL;
doi_getdef_return: doi_getdef_return:
@ -597,7 +597,7 @@ void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
if (!doi_def) if (!doi_def)
return; return;
if (!atomic_dec_and_test(&doi_def->refcount)) if (!refcount_dec_and_test(&doi_def->refcount))
return; return;
spin_lock(&cipso_v4_doi_list_lock); spin_lock(&cipso_v4_doi_list_lock);
list_del_rcu(&doi_def->list); list_del_rcu(&doi_def->list);
@ -630,7 +630,7 @@ int cipso_v4_doi_walk(u32 *skip_cnt,
rcu_read_lock(); rcu_read_lock();
list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list) list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
if (atomic_read(&iter_doi->refcount) > 0) { if (refcount_read(&iter_doi->refcount) > 0) {
if (doi_cnt++ < *skip_cnt) if (doi_cnt++ < *skip_cnt)
continue; continue;
ret_val = callback(iter_doi, cb_arg); ret_val = callback(iter_doi, cb_arg);