diff options
| author | Daiki Ueno <ueno@gnu.org> | 2021-01-29 14:06:32 +0100 |
|---|---|---|
| committer | Daiki Ueno <ueno@gnu.org> | 2021-04-04 10:20:59 +0200 |
| commit | 254ee88e6f20975604b9247d1764c3fcbac448ee (patch) | |
| tree | 7ff5d5fbb543b9b224394f528f51fb758c7ef1e9 | |
| parent | 65695373e10ed0654bff60fe0dcd00137ddfffe8 (diff) | |
| download | gnutls-254ee88e6f20975604b9247d1764c3fcbac448ee.tar.gz | |
key_share: avoid use-after-free around realloc
Signed-off-by: Daiki Ueno <ueno@gnu.org>
| -rw-r--r-- | lib/ext/key_share.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/lib/ext/key_share.c b/lib/ext/key_share.c index ab8abf8fe6..a8c4bb5cff 100644 --- a/lib/ext/key_share.c +++ b/lib/ext/key_share.c @@ -664,14 +664,14 @@ key_share_send_params(gnutls_session_t session, { unsigned i; int ret; - unsigned char *lengthp; - unsigned int cur_length; unsigned int generated = 0; const gnutls_group_entry_st *group; const version_entry_st *ver; /* this extension is only being sent on client side */ if (session->security_parameters.entity == GNUTLS_CLIENT) { + unsigned int length_pos; + ver = _gnutls_version_max(session); if (unlikely(ver == NULL || ver->key_shares == 0)) return 0; @@ -679,16 +679,13 @@ key_share_send_params(gnutls_session_t session, if (!have_creds_for_tls13(session)) return 0; - /* write the total length later */ - lengthp = &extdata->data[extdata->length]; + length_pos = extdata->length; ret = _gnutls_buffer_append_prefix(extdata, 16, 0); if (ret < 0) return gnutls_assert_val(ret); - cur_length = extdata->length; - if (session->internals.hsk_flags & HSK_HRR_RECEIVED) { /* we know the group */ group = get_group(session); if (unlikely(group == NULL)) @@ -736,7 +733,8 @@ key_share_send_params(gnutls_session_t session, } /* copy actual length */ - _gnutls_write_uint16(extdata->length - cur_length, lengthp); + _gnutls_write_uint16(extdata->length - length_pos - 2, + &extdata->data[length_pos]); } else { /* server */ ver = get_version(session); |