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xt_geoip: fix in6_addr little-endian byte swapping

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The Perl script that builds the GeoIP DBs uses inet_pton(3) to convert
the addresses to network byte order. This converts

  "1234:5678::90ab:cdef"

to:

  0x12 0x34 0x56 0x78 .. 0xcd 0xef, interpreted by an LE machine
  accessing this in uint32_t-sized chunks as
  8765:4321::fedc:ba09

The kernel module compares the addresses in packets with the ranges from
the DB in host byte order using binary search. It uses 32-bit swaps
when converting the addresses.

libxt_geoip, however, which the module uses to load the ranges from the
DB and convert them from NBO to HBO, uses 16-bit swaps to do so, and
this means that:

  1234:5678::90ab:cdef

becomes:

  4321:8765::ba09:fedc

Obviously, this is inconsistent with the kernel module and DB build
script and breaks the binary search.

Fixes: b91dbd03c7 ("geoip: store database in network byte order")
Reported-by: "Thomas B. Clark" <kernel@clark.bz>
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
This commit is contained in:
Jeremy Sowden
2019-11-30 18:58:45 +01:00
committed by Jan Engelhardt
parent 6e5edc8372
commit bf1ca298ae
1 changed files with 8 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
extensions/libxt_geoip.c
View File

@@ -50,26 +50,6 @@ static struct option geoip_opts[] = {
};
#if __BYTE_ORDER == __LITTLE_ENDIAN
static void geoip_swap_le16(uint16_t *buf)
{
unsigned char *p = (void *)buf;
uint16_t n= p[0] + (p[1] << 8);
p[0] = (n >> 8) & 0xff;
p[1] = n & 0xff;
}
static void geoip_swap_in6(struct in6_addr *in6)
{
geoip_swap_le16(&in6->s6_addr16[0]);
geoip_swap_le16(&in6->s6_addr16[1]);
geoip_swap_le16(&in6->s6_addr16[2]);
geoip_swap_le16(&in6->s6_addr16[3]);
geoip_swap_le16(&in6->s6_addr16[4]);
geoip_swap_le16(&in6->s6_addr16[5]);
geoip_swap_le16(&in6->s6_addr16[6]);
geoip_swap_le16(&in6->s6_addr16[7]);
}
static void geoip_swap_le32(uint32_t *buf)
{
unsigned char *p = (void *)buf;
@@ -79,6 +59,14 @@ static void geoip_swap_le32(uint32_t *buf)
p[2] = (n >> 8) & 0xff;
p[3] = n & 0xff;
}
static void geoip_swap_in6(struct in6_addr *in6)
{
geoip_swap_le32(&in6->s6_addr32[0]);
geoip_swap_le32(&in6->s6_addr32[1]);
geoip_swap_le32(&in6->s6_addr32[2]);
geoip_swap_le32(&in6->s6_addr32[3]);
}
#endif
static void *