* [bug report] seccomp: Add find_notification helper
@ 2020-06-18 14:27 Dan Carpenter
2020-06-18 21:01 ` Kees Cook
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2020-06-18 14:27 UTC (permalink / raw)
To: sargun; +Cc: bpf, Kees Cook
[ Kees, why am I getting tons and tons of these warnings? Are we not
going to initialize things manually any more? ]
Hello Sargun Dhillon,
The patch 186f03857c48: "seccomp: Add find_notification helper" from
Jun 1, 2020, leads to the following static checker warning:
kernel/seccomp.c:1124 seccomp_notify_recv()
error: uninitialized symbol 'knotif'.
kernel/seccomp.c
1091 static long seccomp_notify_recv(struct seccomp_filter *filter,
1092 void __user *buf)
1093 {
1094 struct seccomp_knotif *knotif, *cur;
^^^^^^
This used to be initialized to NULL here.
1095 struct seccomp_notif unotif;
1096 ssize_t ret;
1097
1098 /* Verify that we're not given garbage to keep struct extensible. */
1099 ret = check_zeroed_user(buf, sizeof(unotif));
1100 if (ret < 0)
1101 return ret;
1102 if (!ret)
1103 return -EINVAL;
1104
1105 memset(&unotif, 0, sizeof(unotif));
1106
1107 ret = down_interruptible(&filter->notif->request);
1108 if (ret < 0)
1109 return ret;
1110
1111 mutex_lock(&filter->notify_lock);
1112 list_for_each_entry(cur, &filter->notif->notifications, list) {
1113 if (cur->state == SECCOMP_NOTIFY_INIT) {
1114 knotif = cur;
^^^^^^^^^^^^
1115 break;
1116 }
1117 }
1118
1119 /*
1120 * If we didn't find a notification, it could be that the task was
1121 * interrupted by a fatal signal between the time we were woken and
1122 * when we were able to acquire the rw lock.
1123 */
1124 if (!knotif) {
^^^^^^
But now it's uninitialized.
1125 ret = -ENOENT;
1126 goto out;
1127 }
1128
1129 unotif.id = knotif->id;
regards,
dan carpenter
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [bug report] seccomp: Add find_notification helper
2020-06-18 14:27 [bug report] seccomp: Add find_notification helper Dan Carpenter
@ 2020-06-18 21:01 ` Kees Cook
2020-06-19 7:37 ` Dan Carpenter
0 siblings, 1 reply; 3+ messages in thread
From: Kees Cook @ 2020-06-18 21:01 UTC (permalink / raw)
To: Dan Carpenter; +Cc: Sargun Dhillon, bpf
On Thu, Jun 18, 2020 at 7:29 AM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> [ Kees, why am I getting tons and tons of these warnings? Are we not
> going to initialize things manually any more? ]
We are, yes. This is "just" a bug.
>
> Hello Sargun Dhillon,
>
> The patch 186f03857c48: "seccomp: Add find_notification helper" from
> Jun 1, 2020, leads to the following static checker warning:
>
> kernel/seccomp.c:1124 seccomp_notify_recv()
> error: uninitialized symbol 'knotif'.
Thanks for the heads-up! This was also reported by the ClangBuiltLinux
project, and I've since fixed it. It should be visible in my
for-next/seccomp tree now.
-Kees
>
> kernel/seccomp.c
> 1091 static long seccomp_notify_recv(struct seccomp_filter *filter,
> 1092 void __user *buf)
> 1093 {
> 1094 struct seccomp_knotif *knotif, *cur;
> ^^^^^^
> This used to be initialized to NULL here.
>
> 1095 struct seccomp_notif unotif;
> 1096 ssize_t ret;
> 1097
> 1098 /* Verify that we're not given garbage to keep struct extensible. */
> 1099 ret = check_zeroed_user(buf, sizeof(unotif));
> 1100 if (ret < 0)
> 1101 return ret;
> 1102 if (!ret)
> 1103 return -EINVAL;
> 1104
> 1105 memset(&unotif, 0, sizeof(unotif));
> 1106
> 1107 ret = down_interruptible(&filter->notif->request);
> 1108 if (ret < 0)
> 1109 return ret;
> 1110
> 1111 mutex_lock(&filter->notify_lock);
> 1112 list_for_each_entry(cur, &filter->notif->notifications, list) {
> 1113 if (cur->state == SECCOMP_NOTIFY_INIT) {
> 1114 knotif = cur;
> ^^^^^^^^^^^^
>
> 1115 break;
> 1116 }
> 1117 }
> 1118
> 1119 /*
> 1120 * If we didn't find a notification, it could be that the task was
> 1121 * interrupted by a fatal signal between the time we were woken and
> 1122 * when we were able to acquire the rw lock.
> 1123 */
> 1124 if (!knotif) {
> ^^^^^^
> But now it's uninitialized.
>
> 1125 ret = -ENOENT;
> 1126 goto out;
> 1127 }
> 1128
> 1129 unotif.id = knotif->id;
>
> regards,
> dan carpenter
--
Kees Cook
--
Kees Cook
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [bug report] seccomp: Add find_notification helper
2020-06-18 21:01 ` Kees Cook
@ 2020-06-19 7:37 ` Dan Carpenter
0 siblings, 0 replies; 3+ messages in thread
From: Dan Carpenter @ 2020-06-19 7:37 UTC (permalink / raw)
To: Kees Cook; +Cc: Sargun Dhillon, bpf
On Thu, Jun 18, 2020 at 02:01:06PM -0700, Kees Cook wrote:
> On Thu, Jun 18, 2020 at 7:29 AM Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >
> > [ Kees, why am I getting tons and tons of these warnings? Are we not
> > going to initialize things manually any more? ]
>
> We are, yes. This is "just" a bug.
GCC has been spotty for some years because of the optimization bug, but
it really feels like something changed recent and I'm getting lots more
warnings now.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-06-19 7:37 UTC | newest]
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2020-06-18 14:27 [bug report] seccomp: Add find_notification helper Dan Carpenter
2020-06-18 21:01 ` Kees Cook
2020-06-19 7:37 ` Dan Carpenter
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