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Commit eb78cd26 authored by Joe Perches's avatar Joe Perches Committed by David S. Miller
Browse files

lib/vsprintf.c: Avoid possible unaligned accesses in %pI6c 



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: default avatarJoe Perches <joe@perches.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 95acf7d7

lib/vsprintf.c

+15 −10
Original line number Diff line number Diff line
@@ -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);

}