From a34349e73348d16d0f41910a38f515f78d18d396 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Fri, 15 Jul 2016 04:56:11 +0200 Subject: [PATCH] network-ndisc: avoid VLAs (#3725) Do not allocate objects of dynamic and potentially large size on the stack to avoid both clang compilation errors and unpredictable runtime behavior on exotic platforms. Use the heap for that instead. While at it, refactor the code a bit. Access 's->domain' via NDISC_DNSSL_DOMAIN(), and refrain from allocating 'x' independently, but rather reuse 's' if we're dealing with a new entry to the set. Fixes #3717 --- src/network/networkd-ndisc.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-) diff --git a/src/network/networkd-ndisc.c b/src/network/networkd-ndisc.c index 2a1ba2b..d9c18b3 100644 --- a/src/network/networkd-ndisc.c +++ b/src/network/networkd-ndisc.c @@ -449,22 +449,24 @@ static void ndisc_router_process_dnssl(Link *link, sd_ndisc_router *rt) { } STRV_FOREACH(i, l) { - struct { - NDiscDNSSL header; - char domain[strlen(*i)]; - } s; + _cleanup_free_ NDiscDNSSL *s; NDiscDNSSL *x; - zero(s.header); - strcpy(s.domain, *i); + s = malloc0(ALIGN(sizeof(NDiscDNSSL)) + strlen(*i) + 1); + if (!s) { + log_oom(); + return; + } + + strcpy(NDISC_DNSSL_DOMAIN(s), *i); if (lifetime == 0) { - (void) set_remove(link->ndisc_dnssl, &s); + (void) set_remove(link->ndisc_dnssl, s); link_dirty(link); continue; } - x = set_get(link->ndisc_dnssl, &s); + x = set_get(link->ndisc_dnssl, s); if (x) { x->valid_until = time_now + lifetime * USEC_PER_SEC; continue; @@ -483,22 +485,15 @@ static void ndisc_router_process_dnssl(Link *link, sd_ndisc_router *rt) { return; } - x = malloc0(ALIGN(sizeof(NDiscDNSSL)) + strlen(*i) + 1); - if (!x) { - log_oom(); - return; - } + s->valid_until = time_now + lifetime * USEC_PER_SEC; - strcpy(NDISC_DNSSL_DOMAIN(x), *i); - x->valid_until = time_now + lifetime * USEC_PER_SEC; - - r = set_put(link->ndisc_dnssl, x); + r = set_put(link->ndisc_dnssl, s); if (r < 0) { - free(x); log_oom(); return; } + s = NULL; assert(r > 0); link_dirty(link); } -- 2.7.4