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Subject[PATCH 1/5] seccomp: Add find_notification helper
Date
This adds a helper which can iterate through a seccomp_filter to
find a notification matching an ID. It removes several replicated
chunks of code.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Cc: Matt Denton <mpdenton@google.com>
Cc: Kees Cook <keescook@google.com>,
Cc: Jann Horn <jannh@google.com>,
Cc: Robert Sesek <rsesek@google.com>,
Cc: Chris Palmer <palmer@google.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Tycho Andersen <tycho@tycho.ws>
---
kernel/seccomp.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 55a6184f5990..f6ce94b7a167 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -1021,10 +1021,25 @@ static int seccomp_notify_release(struct inode *inode, struct file *file)
return 0;
}

+/* must be called with notif_lock held */
+static inline struct seccomp_knotif *
+find_notification(struct seccomp_filter *filter, u64 id)
+{
+ struct seccomp_knotif *cur;
+
+ list_for_each_entry(cur, &filter->notif->notifications, list) {
+ if (cur->id == id)
+ return cur;
+ }
+
+ return NULL;
+}
+
+
static long seccomp_notify_recv(struct seccomp_filter *filter,
void __user *buf)
{
- struct seccomp_knotif *knotif = NULL, *cur;
+ struct seccomp_knotif *knotif, *cur;
struct seccomp_notif unotif;
ssize_t ret;

@@ -1078,14 +1093,8 @@ static long seccomp_notify_recv(struct seccomp_filter *filter,
* may have died when we released the lock, so we need to make
* sure it's still around.
*/
- knotif = NULL;
mutex_lock(&filter->notify_lock);
- list_for_each_entry(cur, &filter->notif->notifications, list) {
- if (cur->id == unotif.id) {
- knotif = cur;
- break;
- }
- }
+ knotif = find_notification(filter, unotif.id);

if (knotif) {
knotif->state = SECCOMP_NOTIFY_INIT;
@@ -1150,7 +1159,7 @@ static long seccomp_notify_send(struct seccomp_filter *filter,
static long seccomp_notify_id_valid(struct seccomp_filter *filter,
void __user *buf)
{
- struct seccomp_knotif *knotif = NULL;
+ struct seccomp_knotif *knotif;
u64 id;
long ret;

@@ -1162,15 +1171,10 @@ static long seccomp_notify_id_valid(struct seccomp_filter *filter,
return ret;

ret = -ENOENT;
- list_for_each_entry(knotif, &filter->notif->notifications, list) {
- if (knotif->id == id) {
- if (knotif->state == SECCOMP_NOTIFY_SENT)
- ret = 0;
- goto out;
- }
- }
+ knotif = find_notification(filter, id);
+ if (knotif && knotif->state == SECCOMP_NOTIFY_SENT)
+ ret = 0;

-out:
mutex_unlock(&filter->notify_lock);
return ret;
}
--
2.25.1
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