From: Yang Yanchao <yangyanchao6@huawei.com>
To: <dan.carpenter@oracle.com>
Cc: <linux-distros@vs.openwall.org>, <linux-media@vger.kernel.org>,
<linux1394-devel@lists.sourceforge.net>, <mchehab@kernel.org>,
<security@kernel.org>
Subject: [PATCH] media firewire firedtv-avc fix a buffer overflow in avc_ca_pmt()
Date: Mon, 7 Jun 2021 15:39:00 +0800 [thread overview]
Message-ID: <20210607073900.1298-1-yangyanchao6@huawei.com> (raw)
For CVE-2021-3542:
1ãread_pos will be added four times in the patch,
so use "read_pos + 4 < length" and write_pos as well
2. The last four bits of c->operand are used for CRC,
so "sizeof (C - > operand) - 4" is used
3. "read_pos+=2" is added after the end of read_pos, so add value (read_pos >= length)
4. In order to avoid memcpy crossing the boundary, es_ info_ length > length - read_ pos
5. When the date_length is a specific input of a construction,it will cause memcpy
to exceed the boundary, "(MSG - > MSG [3] & 0x7F) + date_ length) > (sizeof(msg->msg) - 4)"
Signed-off-by: yangyanchao <yangyanchao6@huawei.com>
---
drivers/media/firewire/firedtv-avc.c | 14 +++++++++++---
drivers/media/firewire/firedtv-ci.c | 2 ++
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/media/firewire/firedtv-avc.c b/drivers/media/firewire/firedtv-avc.c
index 3ef5df164..8c31cf90c 100644
--- a/drivers/media/firewire/firedtv-avc.c
+++ b/drivers/media/firewire/firedtv-avc.c
@@ -1169,7 +1169,11 @@ int avc_ca_pmt(struct firedtv *fdtv, char *msg, int length)
read_pos += program_info_length;
write_pos += program_info_length;
}
- while (read_pos < length) {
+ while (read_pos + 4 < length) {
+ if (write_pos + 4 >= sizeof(c->operand) - 4) {
+ ret = -EINVAL;
+ goto out;
+ }
c->operand[write_pos++] = msg[read_pos++];
c->operand[write_pos++] = msg[read_pos++];
c->operand[write_pos++] = msg[read_pos++];
@@ -1181,13 +1185,17 @@ int avc_ca_pmt(struct firedtv *fdtv, char *msg, int length)
c->operand[write_pos++] = es_info_length >> 8;
c->operand[write_pos++] = es_info_length & 0xff;
if (es_info_length > 0) {
+ if (read_pos >= length) {
+ ret = -EINVAL;
+ goto out;
+ }
pmt_cmd_id = msg[read_pos++];
if (pmt_cmd_id != 1 && pmt_cmd_id != 4)
dev_err(fdtv->device, "invalid pmt_cmd_id %d at stream level\n",
pmt_cmd_id);
- if (es_info_length > sizeof(c->operand) - 4 -
- write_pos) {
+ if (es_info_length > sizeof(c->operand) - 4 - write_pos ||
+ es_info_length > length - read_pos) {
ret = -EINVAL;
goto out;
}
diff --git a/drivers/media/firewire/firedtv-ci.c b/drivers/media/firewire/firedtv-ci.c
index 8dc5a7495..0e7ffa156 100644
--- a/drivers/media/firewire/firedtv-ci.c
+++ b/drivers/media/firewire/firedtv-ci.c
@@ -135,6 +135,8 @@ static int fdtv_ca_pmt(struct firedtv *fdtv, void *arg)
data_length = 0;
for (i = 0; i < (msg->msg[3] & 0x7f); i++)
data_length = (data_length << 8) + msg->msg[data_pos++];
+ if (((msg->msg[3] & 0x7f) + date_length) > (sizeof(msg->msg) - 4))
+ return -EINVAL;
} else {
data_length = msg->msg[3];
}
--
2.23.0
next reply other threads:[~2021-06-07 7:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-07 7:39 Yang Yanchao [this message]
2021-06-07 9:26 ` [PATCH] media firewire firedtv-avc fix a buffer overflow in avc_ca_pmt() Greg KH
2021-06-07 14:28 ` Dan Carpenter
-- strict thread matches above, loose matches on Subject: below --
2021-06-07 7:38 Yang Yanchao
[not found] <000001d73031$d5304480$7f90cd80$@nsfocus.com>
2021-04-14 8:57 ` [PATCH] media: firewire: firedtv-avc: " Dan Carpenter
2021-04-19 21:42 ` Kees Cook
2021-07-19 10:25 ` Dan Carpenter
2021-07-29 10:32 ` Greg KH
2021-08-16 7:01 ` Salvatore Bonaccorso
2021-08-16 7:27 ` [PATCH v2 RESEND] " Dan Carpenter
2021-09-01 10:40 ` Dan Carpenter
2021-09-12 13:14 ` Salvatore Bonaccorso
2021-09-12 18:26 ` Linus Torvalds
2021-09-13 13:23 ` Mauro Carvalho Chehab
2021-09-19 18:45 ` Salvatore Bonaccorso
2021-10-11 7:04 ` Salvatore Bonaccorso
2021-10-11 9:42 ` [PATCH] " Dan Carpenter
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