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authorJakub Kicinski <jakub.kicinski@netronome.com>2017-06-23 04:57:55 +0300
committerDavid S. Miller <davem@davemloft.net>2017-06-23 21:10:05 +0300
commit926f38e9744b2ee6d92085c28ebb50744e9e1182 (patch)
tree8bece0c7338621cebdf5978d5ebce396a2309ac2
parent239946314e57711d7da546b67964d0b387a3ee42 (diff)
downloadlinux-926f38e9744b2ee6d92085c28ebb50744e9e1182.tar.xz
tcp: fix out-of-bounds access in ULP sysctl
KASAN reports out-of-bound access in proc_dostring() coming from proc_tcp_available_ulp() because in case TCP ULP list is empty the buffer allocated for the response will not have anything printed into it. Set the first byte to zero to avoid strlen() going out-of-bounds. Fixes: 734942cc4ea6 ("tcp: ULP infrastructure") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp_ulp.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index e855ea70819b..2417f55374c5 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -88,6 +88,7 @@ void tcp_get_available_ulp(char *buf, size_t maxlen)
struct tcp_ulp_ops *ulp_ops;
size_t offs = 0;
+ *buf = '\0';
rcu_read_lock();
list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) {
offs += snprintf(buf + offs, maxlen - offs,