From: tannerlove tannerlove@google.com

[ Upstream commit 8027bc0307ce59759b90679fa5d8b22949586d20 ]

If user passed an interface option longer than 15 characters, then device.ifr_name and hwtstamp.ifr_name became non-null-terminated strings. The compiler warned about this:

timestamping.c:353:2: warning: ‘strncpy’ specified bound 16 equals \ destination size [-Wstringop-truncation] 353 | strncpy(device.ifr_name, interface, sizeof(device.ifr_name));

Fixes: cb9eff097831 ("net: new user space API for time stamping of incoming and outgoing packets") Signed-off-by: Tanner Love tannerlove@google.com Acked-by: Willem de Bruijn willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/net/timestamping.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/timestamping.c b/tools/testing/selftests/net/timestamping.c index aca3491174a1..f4bb4fef0f39 100644 --- a/tools/testing/selftests/net/timestamping.c +++ b/tools/testing/selftests/net/timestamping.c @@ -313,10 +313,16 @@ int main(int argc, char **argv) int val; socklen_t len; struct timeval next; + size_t if_len;

if (argc < 2) usage(0); interface = argv[1]; + if_len = strlen(interface); + if (if_len >= IFNAMSIZ) { + printf("interface name exceeds IFNAMSIZ\n"); + exit(1); + }

for (i = 2; i < argc; i++) { if (!strcasecmp(argv[i], "SO_TIMESTAMP")) @@ -350,12 +356,12 @@ int main(int argc, char **argv) bail("socket");

memset(&device, 0, sizeof(device)); - strncpy(device.ifr_name, interface, sizeof(device.ifr_name)); + memcpy(device.ifr_name, interface, if_len + 1); if (ioctl(sock, SIOCGIFADDR, &device) < 0) bail("getting interface IP address");

memset(&hwtstamp, 0, sizeof(hwtstamp)); - strncpy(hwtstamp.ifr_name, interface, sizeof(hwtstamp.ifr_name)); + memcpy(hwtstamp.ifr_name, interface, if_len + 1); hwtstamp.ifr_data = (void *)&hwconfig; memset(&hwconfig, 0, sizeof(hwconfig)); hwconfig.tx_type =