nft: fix out of bound memory copy

Valgrind reports an invalid read after a memory block:

==11114== Invalid read of size 8
==11114==    at 0x4C2DB02: memcpy@@GLIBC_2.14 (mc_replace_strmem.c:877)
==11114==    by 0x41788E: add_match (nft.c:781)
==11114==    by 0x41B54C: nft_ipv4_add (nft-ipv4.c:72)
==11114==    by 0x415DF2: nft_rule_new.isra.2 (nft.c:945)
==11114==    by 0x418ACE: nft_rule_append (nft.c:1000)
==11114==    by 0x413A92: add_entry.isra.6 (xtables.c:424)
==11114==    by 0x4152DE: do_commandx (xtables.c:1184)
==11114==    by 0x4134E8: xtables_main (xtables-standalone.c:72)
==11114==    by 0x5B87994: (below main) (libc-start.c:260)
==11114==  Address 0x61399e8 is 8 bytes after a block of size 48 alloc'd
==11114==    at 0x4C2B514: calloc (vg_replace_malloc.c:593)
==11114==    by 0x52448C8: xtables_calloc (xtables.c:272)
==11114==    by 0x410AC2: command_default (xshared.c:150)
==11114==    by 0x4149A2: do_commandx (xtables.c:1075)
==11114==    by 0x4134E8: xtables_main (xtables-standalone.c:72)
==11114==    by 0x5B87994: (below main) (libc-start.c:260)

m->u.match_size also contains the size of the xt_entry_match structure.
Fix also the target path which is very similar.

Reported-by: Ana Rey Botello <anarey@gmail.com>
Tested-by: Ana Rey Botello <anarey@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed