commit e6359eedfbf497e52d52451072aea4713ed80a88 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@xxxxxxxxxxxxxxx>
---
extensions/ebt_string.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/extensions/ebt_string.c b/extensions/ebt_string.c
index 3deff1b..79e24dc 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);
--
2.9.0
--
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