cron2 has submitted this change. ( http://gerrit.openvpn.net/c/openvpn/+/827?usp=email )
Change subject: forward: Fix potential unaligned access in drop_if_recursive_routing ...................................................................... forward: Fix potential unaligned access in drop_if_recursive_routing ASAN error: forward.c:1433:13: runtime error: member access within misaligned address 0x51e00002f52e for type 'const struct in6_addr', which requires 4 byte alignment replace IN6_ARE_ADDR_EQUAL() which uses 32bit compares on Linux - alignment sensitive - with our own OPENVPN_IN6_ARE_ADDR_EQUAL() macro, which always does memcpy() and does not care for alignment. v2: Use memcmp instead of memcpy Change-Id: I74a9eec4954f3f9d208792b6b34357571f76ae4c Signed-off-by: Frank Lichtenheld <fr...@lichtenheld.com> Acked-by: Gert Doering <g...@greenie.muc.de> Message-Id: <20241211171349.8892-1-g...@greenie.muc.de> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg30074.html Signed-off-by: Gert Doering <g...@greenie.muc.de> --- M src/openvpn/forward.c M src/openvpn/proto.h 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c index d50b24c..2c72001 100644 --- a/src/openvpn/forward.c +++ b/src/openvpn/forward.c @@ -1390,8 +1390,6 @@ if (proto_ver == 4) { - const struct openvpn_iphdr *pip; - /* make sure we got whole IP header */ if (BLEN(buf) < ((int) sizeof(struct openvpn_iphdr) + ip_hdr_offset)) { @@ -1404,18 +1402,16 @@ return; } - pip = (struct openvpn_iphdr *) (BPTR(buf) + ip_hdr_offset); + struct openvpn_iphdr *pip = (struct openvpn_iphdr *) (BPTR(buf) + ip_hdr_offset); /* drop packets with same dest addr as gateway */ - if (tun_sa.addr.in4.sin_addr.s_addr == pip->daddr) + if (memcmp(&tun_sa.addr.in4.sin_addr.s_addr, &pip->daddr, sizeof(pip->daddr)) == 0) { drop = true; } } else if (proto_ver == 6) { - const struct openvpn_ipv6hdr *pip6; - /* make sure we got whole IPv6 header */ if (BLEN(buf) < ((int) sizeof(struct openvpn_ipv6hdr) + ip_hdr_offset)) { @@ -1428,9 +1424,10 @@ return; } + struct openvpn_ipv6hdr *pip6 = (struct openvpn_ipv6hdr *) (BPTR(buf) + ip_hdr_offset); + /* drop packets with same dest addr as gateway */ - pip6 = (struct openvpn_ipv6hdr *) (BPTR(buf) + ip_hdr_offset); - if (IN6_ARE_ADDR_EQUAL(&tun_sa.addr.in6.sin6_addr, &pip6->daddr)) + if (OPENVPN_IN6_ARE_ADDR_EQUAL(&tun_sa.addr.in6.sin6_addr, &pip6->daddr)) { drop = true; } diff --git a/src/openvpn/proto.h b/src/openvpn/proto.h index 7b94fbc..0ffeaef 100644 --- a/src/openvpn/proto.h +++ b/src/openvpn/proto.h @@ -83,6 +83,12 @@ #define SIZE_ETH_TO_8021Q_HDR (sizeof(struct openvpn_8021qhdr) \ - sizeof(struct openvpn_ethhdr)) +/** Version of IN6_ARE_ADDR_EQUAL that is guaranteed to work for + * unaligned access. E.g. Linux uses 32bit compares which are + * not safe if the struct is unaligned. */ +#define OPENVPN_IN6_ARE_ADDR_EQUAL(a, b) \ + (memcmp(a, b, sizeof(struct in6_addr)) == 0) + struct openvpn_iphdr { #define OPENVPN_IPH_GET_VER(v) (((v) >> 4) & 0x0F) #define OPENVPN_IPH_GET_LEN(v) (((v) & 0x0F) << 2) -- To view, visit http://gerrit.openvpn.net/c/openvpn/+/827?usp=email To unsubscribe, or for help writing mail filters, visit http://gerrit.openvpn.net/settings Gerrit-Project: openvpn Gerrit-Branch: master Gerrit-Change-Id: I74a9eec4954f3f9d208792b6b34357571f76ae4c Gerrit-Change-Number: 827 Gerrit-PatchSet: 4 Gerrit-Owner: flichtenheld <fr...@lichtenheld.com> Gerrit-Reviewer: cron2 <g...@greenie.muc.de> Gerrit-Reviewer: plaisthos <arne-open...@rfc2549.org> Gerrit-CC: openvpn-devel <openvpn-devel@lists.sourceforge.net> Gerrit-MessageType: merged
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