Help coverity see validation of field_len (#5059)

diff --git a/src/protocols/tacacs/decode.c b/src/protocols/tacacs/decode.c
index b4c6a1c9260ada3c82dfa41da6fb08ae20d3d6bd..bc5884892ac0ddc5ffcb94acf2b81910972a9769 100644 (file)
--- a/src/protocols/tacacs/decode.c
+++ b/src/protocols/tacacs/decode.c
@@ -374,7 +374,7 @@ static int tacacs_decode_field(TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_att
        uint8_t const *p = *field_data;
        fr_pair_t *vp;
 
-       if ((p + field_len) > end) {
+       if (field_len > (end - p)) {
                fr_strerror_printf("'%s' length %u overflows the remaining data (%zu) in the packet",
                                   da->name, field_len, end - p);
                return -1;