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 * may not be used to create, or enable the creation or redistribution of,
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/*
 * ipv6_checksum_offset.c
 *
 * Regression test for rdar://171644699:
 *
 * IPV6_CHECKSUM socket option must reject negative offset values.
 * A previous off-by-one fix changed the bounds check in rip6_output()
 * from (off + 1) to (off + sizeof(uint16_t)), which allowed the value
 * -2 to bypass the check (since -2 + 2 == 0, which is not > plen).
 * This could lead to the packet header being overwritten with a
 * computed checksum value.
 */

#include <darwintest.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <errno.h>

T_GLOBAL_META(
	T_META_NAMESPACE("xnu.net"),
	T_META_ASROOT(true),
	T_META_RADAR_COMPONENT_NAME("xnu"),
	T_META_RADAR_COMPONENT_VERSION("ipv6"),
	T_META_RUN_CONCURRENTLY(true));

static int
set_ipv6_checksum(int s, int val)
{
	return setsockopt(s, IPPROTO_IPV6, IPV6_CHECKSUM, &val, sizeof(val));
}

T_DECL(ipv6_checksum_offset_negative,
    "IPV6_CHECKSUM must reject negative offset values (rdar://171644699)")
{
	int s;

	s = socket(AF_INET6, SOCK_RAW, IPPROTO_NONE);
	T_WITH_ERRNO;
	T_ASSERT_POSIX_SUCCESS(s, "socket(AF_INET6, SOCK_RAW, IPPROTO_NONE)");

	/* -2 was previously accepted due to an integer overflow in the
	 * bounds check in rip6_output(). */
	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, -2), EINVAL,
	    "IPV6_CHECKSUM = -2 should fail with EINVAL");

	/* Other negative even values must also be rejected. */
	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, -4), EINVAL,
	    "IPV6_CHECKSUM = -4 should fail with EINVAL");

	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, -100), EINVAL,
	    "IPV6_CHECKSUM = -100 should fail with EINVAL");

	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, INT32_MIN), EINVAL,
	    "IPV6_CHECKSUM = INT32_MIN should fail with EINVAL");

	/* Odd values (negative and positive) must also be rejected. */
	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, -1), EINVAL,
	    "IPV6_CHECKSUM = -1 should fail with EINVAL");

	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, 1), EINVAL,
	    "IPV6_CHECKSUM = 1 should fail with EINVAL");

	T_EXPECT_POSIX_FAILURE(set_ipv6_checksum(s, 3), EINVAL,
	    "IPV6_CHECKSUM = 3 should fail with EINVAL");

	/* Valid non-negative even offsets must be accepted. */
	T_EXPECT_POSIX_SUCCESS(set_ipv6_checksum(s, 0),
	    "IPV6_CHECKSUM = 0 should succeed");

	T_EXPECT_POSIX_SUCCESS(set_ipv6_checksum(s, 2),
	    "IPV6_CHECKSUM = 2 should succeed");

	T_EXPECT_POSIX_SUCCESS(set_ipv6_checksum(s, 40),
	    "IPV6_CHECKSUM = 40 should succeed");

	close(s);
}