pespin has submitted this change. ( https://gerrit.osmocom.org/c/osmo-uecups/+/40787?usp=email )

Change subject: tun_device: Make sure struct iphdr access is 4-byte aligned ......................................................................

tun_device: Make sure struct iphdr access is 4-byte aligned

"struct iphdr" from netinet/ip.h used in parse_pkt() is not "packed", hence compiler expects to find the struct pointer aligned to 4-bytes. Re-arrange the stack buffer to make sure iphdr ends up being stored aligned.

This was caught by running osmo-uecups with --enable-sanitize in TTCN3 testsuite ttcn3-5gc-test.

Change-Id: I610c8e9b150c234b7d4997e0b1c4d4a9ce4de9ec --- M daemon/tun_device.c 1 file changed, 4 insertions(+), 2 deletions(-)

Approvals: osmith: Looks good to me, but someone else must approve Jenkins Builder: Verified laforge: Looks good to me, but someone else must approve pespin: Looks good to me, approved

diff --git a/daemon/tun_device.c b/daemon/tun_device.c index 350e322..2c67d5c 100644 --- a/daemon/tun_device.c +++ b/daemon/tun_device.c @@ -203,7 +203,9 @@ { struct tun_device *tun = (struct tun_device *)arg; struct gtp_daemon *d = tun->d; - uint8_t base_buffer[sizeof(struct gtp1_header) + sizeof(struct gtp1_exthdr) + MAX_UDP_PACKET]; + /* Make sure "buffer" below ends up aligned to 4byte so that it can access struct iphdr in a 4-byte aligned way. */ + const size_t payload_off_4byte_aligned = ((sizeof(struct gtp1_header) + sizeof(struct gtp1_exthdr)) + 3) & (~0x3); + uint8_t base_buffer[payload_off_4byte_aligned + MAX_UDP_PACKET]; int old_cancelst_unused;

pthread_cleanup_push(tun_device_pthread_cleanup_routine, tun); @@ -216,7 +218,7 @@ struct gtp_tunnel *t; struct pkt_info pinfo; int rc, nread; - uint8_t *buffer = base_buffer + sizeof(base_buffer) - MAX_UDP_PACKET; + uint8_t *buffer = base_buffer + payload_off_4byte_aligned;

/* 1) read from tun */ rc = read(tun->fd, buffer, MAX_UDP_PACKET);