From f1993dc4e0b33050b8f72a3558ee88b24c4063b2 Mon Sep 17 00:00:00 2001 From: Peter Popovec Date: Tue, 27 Jun 2023 09:50:42 +0200 Subject: [PATCH] myeid: fixed CID 380538 Out-of-bounds read (OVERRUN) also fixes output buffer size checking --- src/libopensc/card-myeid.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/src/libopensc/card-myeid.c b/src/libopensc/card-myeid.c index 4ee4246840..50e78ff1d8 100644 --- a/src/libopensc/card-myeid.c +++ b/src/libopensc/card-myeid.c @@ -1986,18 +1986,20 @@ myeid_enc_dec_sym(struct sc_card *card, const u8 *data, size_t datalen, sc_log(ctx, "Found padding byte %02x", pad_byte); if (pad_byte == 0 || pad_byte > block_size) LOG_FUNC_RETURN(ctx, SC_ERROR_WRONG_PADDING); - sdata = priv->sym_plain_buffer + block_size - pad_byte; + sdata = priv->sym_plain_buffer + block_size; for (i = 0; i < pad_byte; i++) - if (sdata[i] != pad_byte) + if (*(--sdata) != pad_byte) LOG_FUNC_RETURN(ctx, SC_ERROR_WRONG_PADDING); return_len = block_size - pad_byte; } - *outlen = return_len; /* application can request buffer size or actual buffer size is too small */ - if (out == NULL) + if (out == NULL) { + *outlen = return_len; LOG_FUNC_RETURN(ctx, SC_SUCCESS); + } if (return_len > *outlen) LOG_FUNC_RETURN(ctx, SC_ERROR_BUFFER_TOO_SMALL); + *outlen = return_len; memcpy(out, priv->sym_plain_buffer, return_len); sc_log(ctx, "C_DecryptFinal %zu bytes", *outlen); return SC_SUCCESS;