From patchwork Fri Sep 18 23:04:06 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Perches X-Patchwork-Id: 33905 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 3FB5DB7B7A for ; Sat, 19 Sep 2009 09:04:14 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758790AbZIRXEG (ORCPT ); Fri, 18 Sep 2009 19:04:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758744AbZIRXEF (ORCPT ); Fri, 18 Sep 2009 19:04:05 -0400 Received: from mail.perches.com ([173.55.12.10]:1026 "EHLO mail.perches.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758295AbZIRXEE (ORCPT ); Fri, 18 Sep 2009 19:04:04 -0400 Received: from [192.168.1.151] (Joe-Laptop.home [192.168.1.151]) by mail.perches.com (Postfix) with ESMTP id 36BA824368; Fri, 18 Sep 2009 16:04:03 -0700 (PDT) Subject: [PATCH] lib/vsprintf.c: Avoid possible unaligned accesses in %pI6c From: Joe Perches To: netdev Cc: Jens Rosenboom , David Miller Date: Fri, 18 Sep 2009 16:04:06 -0700 Message-Id: <1253315046.2543.475.camel@Joe-Laptop.home> Mime-Version: 1.0 X-Mailer: Evolution 2.27.92 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jens Rosenboom noticed that a possibly unaligned const char* is cast to a const struct in6_addr *. Avoid this at the cost of a struct in6_addr copy on the stack. Signed-off-by: Joe Perches --- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/lib/vsprintf.c b/lib/vsprintf.c index d320c18..5d299d0 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -671,7 +671,7 @@ static char *ip4_string(char *p, const u8 *addr, bool leading_zeros) return p; } -static char *ip6_compressed_string(char *p, const struct in6_addr *addr) +static char *ip6_compressed_string(char *p, const char *addr) { int i; int j; @@ -683,7 +683,12 @@ static char *ip6_compressed_string(char *p, const struct in6_addr *addr) u8 hi; u8 lo; bool needcolon = false; - bool useIPv4 = ipv6_addr_v4mapped(addr) || ipv6_addr_is_isatap(addr); + bool useIPv4; + struct in6_addr in6; + + memcpy(&in6, addr, sizeof(struct in6_addr)); + + useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6); memset(zerolength, 0, sizeof(zerolength)); @@ -695,7 +700,7 @@ static char *ip6_compressed_string(char *p, const struct in6_addr *addr) /* find position of longest 0 run */ for (i = 0; i < range; i++) { for (j = i; j < range; j++) { - if (addr->s6_addr16[j] != 0) + if (in6.s6_addr16[j] != 0) break; zerolength[i]++; } @@ -722,7 +727,7 @@ static char *ip6_compressed_string(char *p, const struct in6_addr *addr) needcolon = false; } /* hex u16 without leading 0s */ - word = ntohs(addr->s6_addr16[i]); + word = ntohs(in6.s6_addr16[i]); hi = word >> 8; lo = word & 0xff; if (hi) { @@ -741,19 +746,19 @@ static char *ip6_compressed_string(char *p, const struct in6_addr *addr) if (useIPv4) { if (needcolon) *p++ = ':'; - p = ip4_string(p, &addr->s6_addr[12], false); + p = ip4_string(p, &in6.s6_addr[12], false); } *p = '\0'; return p; } -static char *ip6_string(char *p, const struct in6_addr *addr, const char *fmt) +static char *ip6_string(char *p, const char *addr, const char *fmt) { int i; for (i = 0; i < 8; i++) { - p = pack_hex_byte(p, addr->s6_addr[2 * i]); - p = pack_hex_byte(p, addr->s6_addr[2 * i + 1]); + p = pack_hex_byte(p, *addr++); + p = pack_hex_byte(p, *addr++); if (fmt[0] == 'I' && i != 7) *p++ = ':'; } @@ -768,9 +773,9 @@ static char *ip6_addr_string(char *buf, char *end, const u8 *addr, char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")]; if (fmt[0] == 'I' && fmt[2] == 'c') - ip6_compressed_string(ip6_addr, (const struct in6_addr *)addr); + ip6_compressed_string(ip6_addr, addr); else - ip6_string(ip6_addr, (const struct in6_addr *)addr, fmt); + ip6_string(ip6_addr, addr, fmt); return string(buf, end, ip6_addr, spec); }