[PATCH 4.4 42/73] tipc: check msg->req data len in tipc_nl_compat_bearer_disable

Greg Kroah-Hartman
2019-07-08T15:49:30Z

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit 4f07b80c973348a99b5d2a32476a2e7877e94a05 ]

This patch is to fix an uninit-value issue, reported by syzbot:

BUG: KMSAN: uninit-value in memchr+0xce/0x110 lib/string.c:981
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x191/0x1f0 lib/dump_stack.c:113
kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622
__msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310
memchr+0xce/0x110 lib/string.c:981
string_is_valid net/tipc/netlink_compat.c:176 [inline]
tipc_nl_compat_bearer_disable+0x2a1/0x480 net/tipc/netlink_compat.c:449
__tipc_nl_compat_doit net/tipc/netlink_compat.c:327 [inline]
tipc_nl_compat_doit+0x3ac/0xb00 net/tipc/netlink_compat.c:360
tipc_nl_compat_handle net/tipc/netlink_compat.c:1178 [inline]
tipc_nl_compat_recv+0x1b1b/0x27b0 net/tipc/netlink_compat.c:1281

TLV_GET_DATA_LEN() may return a negtive int value, which will be
used as size_t (becoming a big unsigned long) passed into memchr,
cause this issue.

Similar to what it does in tipc_nl_compat_bearer_enable(), this
fix is to return -EINVAL when TLV_GET_DATA_LEN() is negtive in
tipc_nl_compat_bearer_disable(), as well as in
tipc_nl_compat_link_stat_dump() and tipc_nl_compat_link_reset_stats().

v1->v2:
- add the missing Fixes tags per Eric's request.

Fixes: 0762216c0ad2 ("tipc: fix uninit-value in tipc_nl_compat_bearer_enable")
Fixes: 8b66fee7f8ee ("tipc: fix uninit-value in tipc_nl_compat_link_reset_stats")
Reported-by: syzbot+30eaa8bf392f7fafffaf@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/tipc/netlink_compat.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c
@@ -430,7 +430,11 @@ static int tipc_nl_compat_bearer_disable
if (!bearer)
return -EMSGSIZE;

- len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME);
+ len = TLV_GET_DATA_LEN(msg->req);
+ if (len <= 0)
+ return -EINVAL;
+
+ len = min_t(int, len, TIPC_MAX_BEARER_NAME);
if (!string_is_valid(name, len))
return -EINVAL;

@@ -505,7 +509,11 @@ static int tipc_nl_compat_link_stat_dump

name = (char *)TLV_DATA(msg->req);

- len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_LINK_NAME);
+ len = TLV_GET_DATA_LEN(msg->req);
+ if (len <= 0)
+ return -EINVAL;
+
+ len = min_t(int, len, TIPC_MAX_BEARER_NAME);
if (!string_is_valid(name, len))
return -EINVAL;

@@ -776,7 +784,11 @@ static int tipc_nl_compat_link_reset_sta
if (!link)
return -EMSGSIZE;

- len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_LINK_NAME);
+ len = TLV_GET_DATA_LEN(msg->req);
+ if (len <= 0)
+ return -EINVAL;
+
+ len = min_t(int, len, TIPC_MAX_BEARER_NAME);
if (!string_is_valid(name, len))
return -EINVAL;