From 687b3c65c0460dd8c4ba7e63e3ae0ab20836e6e8 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Fri, 22 Jan 2016 20:57:34 +0000 Subject: [PATCH] Fix alignment of buffers in ra_process and dhcpv6_request The packet buffer needs to be 32-bit aligned to ensure that the various 32-bit fields we pick out are naturally aligned. The control message buffers needs to be naturally aligned for struct cmsghdr. Signed-off-by: Ben Hutchings --- src/dhcpv6.c | 4 +++- src/odhcp6c.h | 1 + src/ra.c | 3 ++- 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/src/dhcpv6.c b/src/dhcpv6.c index e27d899..8a1231d 100644 --- a/src/dhcpv6.c +++ b/src/dhcpv6.c @@ -577,7 +577,9 @@ int dhcpv6_request(enum dhcpv6_msg type) // Receive rounds for (; len < 0 && (round_start < round_end); round_start = odhcp6c_get_milli_time()) { - uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]; + uint8_t buf[1536]; + uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] + __aligned(__alignof__(struct cmsghdr)); struct iovec iov = {buf, sizeof(buf)}; struct sockaddr_in6 addr; struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr), diff --git a/src/odhcp6c.h b/src/odhcp6c.h index 98d91dd..08a816f 100644 --- a/src/odhcp6c.h +++ b/src/odhcp6c.h @@ -18,6 +18,7 @@ #define _unused __attribute__((unused)) #define _packed __attribute__((packed)) +#define __aligned(n) __attribute__((aligned(n))) #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) diff --git a/src/ra.c b/src/ra.c index 2d442f6..dd5962a 100644 --- a/src/ra.c +++ b/src/ra.c @@ -274,7 +274,8 @@ bool ra_process(void) { bool found = false; bool changed = false; - uint8_t buf[1500], cmsg_buf[128]; + uint8_t buf[1500] __aligned(4); + uint8_t cmsg_buf[128] __aligned(__alignof__(struct cmsghdr)); struct nd_router_advert *adv = (struct nd_router_advert*)buf; struct odhcp6c_entry *entry = alloca(sizeof(*entry) + 256); const struct in6_addr any = IN6ADDR_ANY_INIT; -- 2.39.2