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authorKees Cook <keescook@chromium.org>2017-06-26 09:24:00 -0700
committerKees Cook <keescook@chromium.org>2017-06-26 09:24:00 -0700
commit0b5fa2290637a3235898d18dc0e7a136783f1bd2 (patch)
treefa350a4ac455aace74b1aa5b584a1f9afef8e770 /kernel/seccomp.c
parent93bd70e3330be45542c455dde11d8dc657ab3044 (diff)
seccomp: Switch from atomic_t to recount_t
This switches the seccomp usage tracking from atomic_t to refcount_t to gain refcount overflow protections. Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: David Windsor <dwindsor@gmail.com> Cc: Hans Liljestrand <hans.liljestrand@aalto.fi> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'kernel/seccomp.c')
-rw-r--r--kernel/seccomp.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index fce83885b7ef..98b59b5db90b 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -13,7 +13,7 @@
* of Berkeley Packet Filters/Linux Socket Filters.
*/
-#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/audit.h>
#include <linux/compat.h>
#include <linux/coredump.h>
@@ -56,7 +56,7 @@
* to a task_struct (other than @usage).
*/
struct seccomp_filter {
- atomic_t usage;
+ refcount_t usage;
struct seccomp_filter *prev;
struct bpf_prog *prog;
};
@@ -378,7 +378,7 @@ static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
return ERR_PTR(ret);
}
- atomic_set(&sfilter->usage, 1);
+ refcount_set(&sfilter->usage, 1);
return sfilter;
}
@@ -465,7 +465,7 @@ void get_seccomp_filter(struct task_struct *tsk)
if (!orig)
return;
/* Reference count is bounded by the number of total processes. */
- atomic_inc(&orig->usage);
+ refcount_inc(&orig->usage);
}
static inline void seccomp_filter_free(struct seccomp_filter *filter)
@@ -481,7 +481,7 @@ void put_seccomp_filter(struct task_struct *tsk)
{
struct seccomp_filter *orig = tsk->seccomp.filter;
/* Clean up single-reference branches iteratively. */
- while (orig && atomic_dec_and_test(&orig->usage)) {
+ while (orig && refcount_dec_and_test(&orig->usage)) {
struct seccomp_filter *freeme = orig;
orig = orig->prev;
seccomp_filter_free(freeme);