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decode-mime: fix body md5 computation

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Previous code was wrongly supposing the lines are ending with CRLF.
But this is not the case so we must propagate the length of end of
line delimiter to be able to compute the md5 of the mail body.
pull/1671/head
Eric Leblond 10 years ago
parent 53419b93c8
commit 2ecab3f765
3 changed files with 37 additions and 34 deletions
Show Stats Download Patch File Download Diff File

3
src/app-layer-smtp.c
Unescape Escape View File

@ -813,7 +813,8 @@ static int SMTPProcessCommandDATA(SMTPState *state, Flow *f,
if (smtp_config.decode_mime && state->curr_tx->mime_state) {
int ret = MimeDecParseLine((const uint8_t *) state->current_line,
state->current_line_len, state->curr_tx->mime_state);
state->current_line_len, state->current_line_delimiter_len,
state->curr_tx->mime_state);
if (ret != MIME_DEC_OK) {
SCLogDebug("MimeDecParseLine() function returned an error code: %d", ret);
}

65
src/util-decode-mime.c
Unescape Escape View File

@ -2040,6 +2040,13 @@ static int ProcessBodyComplete(MimeDecParseState *state)
}
}
#ifdef HAVE_NSS
if (state->md5_ctx) {
unsigned int len = 0;
HASH_End(state->md5_ctx, state->md5, &len, sizeof(state->md5));
}
#endif
/* Invoke pre-processor and callback with remaining data */
ret = ProcessDecodedDataChunk(state->data_chunk, state->data_chunk_len, state);
if (ret != MIME_DEC_OK) {
@ -2209,12 +2216,14 @@ static int ProcessMimeBody(const uint8_t *buf, uint32_t len,
uint32_t tlen;
#ifdef HAVE_NSS
if (MimeDecGetConfig()->body_md5 && state->body_begin == 1 && (state->md5_ctx == NULL)) {
state->md5_ctx = HASH_Create(HASH_AlgMD5);
if (state->md5_ctx != NULL) {
HASH_Begin(state->md5_ctx);
HASH_Update(state->md5_ctx, buf, len + 2); /* plus 2 to add CRLF */
if (MimeDecGetConfig()->body_md5) {
if (state->body_begin == 1) {
if (state->md5_ctx == NULL) {
state->md5_ctx = HASH_Create(HASH_AlgMD5);
HASH_Begin(state->md5_ctx);
}
}
HASH_Update(state->md5_ctx, buf, len + state->current_line_delimiter_len);
}
#endif
@ -2474,13 +2483,6 @@ int MimeDecParseComplete(MimeDecParseState *state)
return ret;
}
#ifdef HAVE_NSS
if (state->md5_ctx) {
unsigned int len = 0;
HASH_End(state->md5_ctx, state->md5, &len, sizeof(state->md5));
}
#endif
if (state->stack->top == NULL) {
state->msg->anomaly_flags |= ANOM_MALFORMED_MSG;
SCLogDebug("Error: Message is malformed");
@ -2513,12 +2515,13 @@ int MimeDecParseComplete(MimeDecParseState *state)
*
* \param line A string representing the line (w/out CRLF)
* \param len The length of the line
* \param delim_len The length of the line end delimiter
* \param state The parser state
*
* \return MIME_DEC_OK on success, otherwise < 0 on failure
*/
int MimeDecParseLine(const uint8_t *line, const uint32_t len,
MimeDecParseState *state)
const uint8_t delim_len, MimeDecParseState *state)
{
int ret = MIME_DEC_OK;
@ -2529,11 +2532,7 @@ int MimeDecParseLine(const uint8_t *line, const uint32_t len,
SCLogDebug("SMTP LINE - EMPTY");
}
#ifdef HAVE_NSS
if (state->md5_ctx) {
HASH_Update(state->md5_ctx, line, len + 2);
}
#endif
state->current_line_delimiter_len = delim_len;
/* Process the entity */
ret = ProcessMimeEntity(line, len, state);
if (ret != MIME_DEC_OK) {
@ -2581,8 +2580,10 @@ MimeDecEntity * MimeDecParseFullMsg(const uint8_t *buf, uint32_t blen, void *dat
line = tok;
state->current_line_delimiter_len = (remainPtr - tok) - tokLen;
/* Parse the line */
ret = MimeDecParseLine(line, tokLen, state);
ret = MimeDecParseLine(line, tokLen,
(remainPtr - tok) - tokLen, state);
if (ret != MIME_DEC_OK) {
SCLogDebug("Error: MimeDecParseLine() function failed: %d",
ret);
@ -2669,25 +2670,25 @@ static int MimeDecParseLineTest01(void)
TestDataChunkCallback);
char *str = "From: Sender1";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "To: Recipient1";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "Content-Type: text/plain";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "A simple message line 1";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "A simple message line 2";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "A simple message line 3";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
if (ret != MIME_DEC_OK) {
return ret;
@ -2737,23 +2738,23 @@ static int MimeDecParseLineTest02(void)
TestDataChunkCallback);
char *str = "From: Sender1";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "To: Recipient1";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "Content-Type: text/plain";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "A simple message line 1";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
str = "A simple message line 2 click on http://www.test.com/malware.exe?"
"hahah hopefully you click this link";
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), state);
ret |= MimeDecParseLine((uint8_t *)str, strlen(str), 1, state);
if (ret != MIME_DEC_OK) {
return ret;

3
src/util-decode-mime.h
Unescape Escape View File

@ -207,6 +207,7 @@ typedef struct MimeDecParseState {
int found_child; /**< Flag indicating a child entity was found */
int body_begin; /**< Currently at beginning of body */
int body_end; /**< Currently at end of body */
uint8_t current_line_delimiter_len; /**< Length of line delimiter */
void *data; /**< Pointer to data specific to the caller */
int (*DataChunkProcessorFunc) (const uint8_t *chunk, uint32_t len,
struct MimeDecParseState *state); /**< Data chunk processing function callback */
@ -236,7 +237,7 @@ MimeDecParseState * MimeDecInitParser(void *data, int (*dcpfunc)(const uint8_t *
uint32_t len, MimeDecParseState *state));
void MimeDecDeInitParser(MimeDecParseState *state);
int MimeDecParseComplete(MimeDecParseState *state);
int MimeDecParseLine(const uint8_t *line, const uint32_t len, MimeDecParseState *state);
int MimeDecParseLine(const uint8_t *line, const uint32_t len, const uint8_t delim_len, MimeDecParseState *state);
MimeDecEntity * MimeDecParseFullMsg(const uint8_t *buf, uint32_t blen, void *data,
int (*DataChunkProcessorFunc)(const uint8_t *chunk, uint32_t len, MimeDecParseState *state));
const char *MimeDecParseStateGetStatus(MimeDecParseState *state);

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