[PATCH 3.16 071/157] ALSA: seq: Fix OOB-reads from strlcpy

From: Ben Hutchings
Date: Sat Aug 10 2019 - 16:46:23 EST


3.16.72-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Zubin Mithra <zsm@xxxxxxxxxxxx>

commit 212ac181c158c09038c474ba68068be49caecebb upstream.

When ioctl calls are made with non-null-terminated userspace strings,
strlcpy causes an OOB-read from within strlen. Fix by changing to use
strscpy instead.

Signed-off-by: Zubin Mithra <zsm@xxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
sound/core/seq/seq_clientmgr.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/sound/core/seq/seq_clientmgr.c
+++ b/sound/core/seq/seq_clientmgr.c
@@ -1249,7 +1249,7 @@ static int snd_seq_ioctl_set_client_info

/* fill the info fields */
if (client_info.name[0])
- strlcpy(client->name, client_info.name, sizeof(client->name));
+ strscpy(client->name, client_info.name, sizeof(client->name));

client->filter = client_info.filter;
client->event_lost = client_info.event_lost;
@@ -1564,7 +1564,7 @@ static int snd_seq_ioctl_create_queue(st
/* set queue name */
if (! info.name[0])
snprintf(info.name, sizeof(info.name), "Queue-%d", q->queue);
- strlcpy(q->name, info.name, sizeof(q->name));
+ strscpy(q->name, info.name, sizeof(q->name));
queuefree(q);

if (copy_to_user(arg, &info, sizeof(info)))
@@ -1642,7 +1642,7 @@ static int snd_seq_ioctl_set_queue_info(
queuefree(q);
return -EPERM;
}
- strlcpy(q->name, info.name, sizeof(q->name));
+ strscpy(q->name, info.name, sizeof(q->name));
queuefree(q);

return 0;