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author | Duncan Roe <duncan_roe@optusnet.com.au> | 2018-06-15 11:31:56 +1000 |
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committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-06-28 17:19:04 +0200 |
commit | 53d7e7a85207fdb1ce8612a12a6bc94710ecc552 (patch) | |
tree | 4f397de648c62ffe6b4ada415c237a9d2ac1f81e | |
parent | 56993546c80576986930f9bae7ae4ba744b1e508 (diff) | |
download | ebtables-53d7e7a85207fdb1ce8612a12a6bc94710ecc552.tar.gz |
extensions: ebt_string: take action if snprintf discards data
56993546c805 ("extensions: fix build failure on fc28") eliminated a gcc
warning that strncpy could make a string w/out a NUL terminator.
snprintf guarantees NUL-termination (so fixes that possibility). But,
snprintf may discard data to make room for the NUL. This patch errors
straight away in that eventuality.
Signed-off-by: Duncan Roe <duncan_roe@optusnet.com.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-rw-r--r-- | extensions/ebt_string.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/extensions/ebt_string.c b/extensions/ebt_string.c index 3deff1b..7d24f80 100644 --- a/extensions/ebt_string.c +++ b/extensions/ebt_string.c @@ -168,7 +168,9 @@ static int parse(int c, char **argv, int argc, const struct ebt_u_entry *entry, ebt_check_option2(flags, OPT_STRING_ALGO); if (ebt_check_inverse2(optarg)) ebt_print_error2("Unexpected `!' after --string-algo"); - snprintf(info->algo, sizeof(info->algo), "%s", optarg); + if (snprintf(info->algo, sizeof(info->algo), "%s", optarg) >= + sizeof(info->algo)) + ebt_print_error2("\"%s\" is truncated", info->algo); break; case STRING_ICASE: ebt_check_option2(flags, OPT_STRING_ICASE); |