Use strlen(), otherwise mpz_import_data() reads too much beyond the real chain string. ==2759== Invalid read of size 1 ==2759== at 0x67D68D6: __gmpz_import (in /usr/lib/x86_64-linux-gnu/libgmp.so.10.3.2) ==2759== by 0x4E79467: mpz_import_data (gmputil.c:133) ==2759== by 0x4E60A12: constant_expr_alloc (expression.c:375) ==2759== by 0x4E8ED65: nft_parse (parser_bison.y:3825) ==2759== by 0x4E7E850: nft_parse_bison_buffer (libnftables.c:357) ==2759== by 0x4E7E850: nft_run_cmd_from_buffer (libnftables.c:424) ==2759== by 0x1095D4: main (in /home/pablo/asuntos/netfilter/nftables-bugs/nft7/a.out) ==2759== Address 0x6ee1b4a is 0 bytes after a block of size 10 alloc'd ==2759== at 0x4C2BBAF: malloc (vg_replace_malloc.c:299) ==2759== by 0x59FD3B9: strdup (strdup.c:42) ==2759== by 0x4E7963D: xstrdup (utils.c:75) ==2759== by 0x4E9C233: nft_lex (scanner.l:626) ==2759== by 0x4E8E382: nft_parse (parser_bison.c:5297) ==2759== by 0x4E7E850: nft_parse_bison_buffer (libnftables.c:357) ==2759== by 0x4E7E850: nft_run_cmd_from_buffer (libnftables.c:424) Fixes: f1e8a129ee42 ("src: Introduce chain_expr in jump and goto statements") Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> --- src/netlink.c | 4 ++-- src/parser_bison.y | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/src/netlink.c b/src/netlink.c index ef12cb016b1d..e9779684ac09 100644 --- a/src/netlink.c +++ b/src/netlink.c @@ -265,8 +265,8 @@ static struct expr *netlink_alloc_verdict(const struct location *loc, case NFT_GOTO: chain = constant_expr_alloc(loc, &string_type, BYTEORDER_HOST_ENDIAN, - NFT_CHAIN_MAXNAMELEN * - BITS_PER_BYTE, nld->chain); + strlen(nld->chain) * BITS_PER_BYTE, + nld->chain); break; default: chain = NULL; diff --git a/src/parser_bison.y b/src/parser_bison.y index 8026708ed859..5ffb5cc22145 100644 --- a/src/parser_bison.y +++ b/src/parser_bison.y @@ -3824,8 +3824,8 @@ chain_expr : variable_expr { $$ = constant_expr_alloc(&@$, &string_type, BYTEORDER_HOST_ENDIAN, - NFT_CHAIN_MAXNAMELEN * - BITS_PER_BYTE, $1); + strlen($1) * BITS_PER_BYTE, + $1); } ; -- 2.11.0