From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp16.mail.ru (smtp16.mail.ru [94.100.176.153]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 199DE4765E0 for ; Thu, 24 Dec 2020 15:28:29 +0300 (MSK) References: <1d01852e7d3d8360e7175807150f625018579c82.1608633086.git.void@tarantool.org> From: Leonid Vasiliev Message-ID: Date: Thu, 24 Dec 2020 15:28:23 +0300 MIME-Version: 1.0 In-Reply-To: <1d01852e7d3d8360e7175807150f625018579c82.1608633086.git.void@tarantool.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Tarantool-patches] [PATCH v3 1/2] base64: fix decoder output buffer overrun (reads) List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Sergey Nikiforov , tarantool-patches@dev.tarantool.org Cc: Vladislav Shpilevoy Hi! Thank you for the patch. I have some comments: - Why are you adding a test in the next commit? Seems like this test is validating this fix. - I agree with Vlad that the test should be moved to a separate test function. The changes in third_party/base64.c - LGTM. On 22.12.2020 13:41, Sergey Nikiforov wrote: > Was caught by base64 test with enabled ASAN. > > It also caused data corruption - garbage instead of "extra bits" was > saved into state->result if there was no space in output buffer. > > Fixes: #3069 > --- > > Branch: https://github.com/tarantool/tarantool/tree/void234/gh-3069-fix-base64-memory-overrun-v3 > Issue: https://github.com/tarantool/tarantool/issues/3069 > > third_party/base64.c | 28 +++++++++++++++++----------- > 1 file changed, 17 insertions(+), 11 deletions(-) > > diff --git a/third_party/base64.c b/third_party/base64.c > index 8ecab23eb..3350a98ff 100644 > --- a/third_party/base64.c > +++ b/third_party/base64.c > @@ -247,8 +247,9 @@ base64_decode_block(const char *in_base64, int in_len, > char *out_pos = out_bin; > char *out_end = out_bin + out_len; > int fragment; > + char curr_byte; > > - *out_pos = state->result; > + curr_byte = state->result; > > switch (state->step) > { > @@ -259,49 +260,54 @@ base64_decode_block(const char *in_base64, int in_len, > if (in_pos == in_end || out_pos >= out_end) > { > state->step = step_a; > - state->result = *out_pos; > + state->result = curr_byte; > return out_pos - out_bin; > } > fragment = base64_decode_value(*in_pos++); > } while (fragment < 0); > - *out_pos = (fragment & 0x03f) << 2; > + curr_byte = (fragment & 0x03f) << 2; > case step_b: > do { > if (in_pos == in_end || out_pos >= out_end) > { > state->step = step_b; > - state->result = *out_pos; > + state->result = curr_byte; > return out_pos - out_bin; > } > fragment = base64_decode_value(*in_pos++); > } while (fragment < 0); > - *out_pos++ |= (fragment & 0x030) >> 4; > + curr_byte |= (fragment & 0x030) >> 4; > + *out_pos++ = curr_byte; > + curr_byte = (fragment & 0x00f) << 4; > if (out_pos < out_end) > - *out_pos = (fragment & 0x00f) << 4; > + *out_pos = curr_byte; > case step_c: > do { > if (in_pos == in_end || out_pos >= out_end) > { > state->step = step_c; > - state->result = *out_pos; > + state->result = curr_byte; > return out_pos - out_bin; > } > fragment = base64_decode_value(*in_pos++); > } while (fragment < 0); > - *out_pos++ |= (fragment & 0x03c) >> 2; > + curr_byte |= (fragment & 0x03c) >> 2; > + *out_pos++ = curr_byte; > + curr_byte = (fragment & 0x003) << 6; > if (out_pos < out_end) > - *out_pos = (fragment & 0x003) << 6; > + *out_pos = curr_byte; > case step_d: > do { > if (in_pos == in_end || out_pos >= out_end) > { > state->step = step_d; > - state->result = *out_pos; > + state->result = curr_byte; > return out_pos - out_bin; > } > fragment = base64_decode_value(*in_pos++); > } while (fragment < 0); > - *out_pos++ |= (fragment & 0x03f); > + curr_byte |= (fragment & 0x03f); > + *out_pos++ = curr_byte; > } > } > /* control should not reach here */ >