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Request header invalid 6415 v3 #411

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Request header invalid 6415 v3 #411

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935a9f8
request: continue processing even with invalid headers
catenacyber Nov 6, 2023
9ee86ed
request: be more liberal about transfer-encoding value
catenacyber Nov 6, 2023
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2 changes: 2 additions & 0 deletions htp/htp_private.h
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Original file line number Diff line number Diff line change
Expand Up @@ -248,6 +248,8 @@ htp_status_t htp_tx_urldecode_params_inplace(htp_tx_t *tx, bstr *input);

void htp_connp_destroy_decompressors(htp_connp_t *connp);

htp_status_t htp_header_has_token(const unsigned char *hvp, size_t hvlen, const unsigned char *value);

#ifndef HAVE_STRLCAT
size_t strlcat(char *dst, const char *src, size_t size);
#endif
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7 changes: 2 additions & 5 deletions htp/htp_transaction.c
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Expand Up @@ -405,7 +405,7 @@ static htp_status_t htp_tx_process_request_headers(htp_tx_t *tx) {
// (2.2.22 on Ubuntu 12.04 LTS) instead errors out with "Unknown Transfer-Encoding: identity".
// And it behaves strangely, too, sending a 501 and proceeding to process the request
// (e.g., PHP is run), but without the body. It then closes the connection.
if (bstr_cmp_c_nocase(te->value, "chunked") != 0) {
if (htp_header_has_token(bstr_ptr(te->value), bstr_len(te->value), (unsigned char*) "chunked") != HTP_OK) {
// Invalid T-E header value.
tx->request_transfer_coding = HTP_CODING_INVALID;
tx->flags |= HTP_REQUEST_INVALID_T_E;
Expand Down Expand Up @@ -585,10 +585,7 @@ static htp_status_t htp_tx_process_request_headers(htp_tx_t *tx) {
rc = htp_hook_run_all(tx->connp->cfg->hook_request_headers, tx);
if (rc != HTP_OK) return rc;

// We cannot proceed if the request is invalid.
if (tx->flags & HTP_REQUEST_INVALID) {
return HTP_ERROR;
}
// We still proceed if the request is invalid.

return HTP_OK;
}
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51 changes: 51 additions & 0 deletions htp/htp_util.c
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Expand Up @@ -2536,3 +2536,54 @@ htp_uri_t *htp_uri_alloc(void) {
char *htp_get_version(void) {
return HTP_VERSION_STRING_FULL;
}

htp_status_t htp_header_has_token(const unsigned char *hvp, size_t hvlen, const unsigned char *value) {
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hvp is haystack, value is needle?

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yes, and haystack is header value, value is token to look for

int state = 0;
// offset to compare in value
size_t v_off = 0;
for (size_t i = 0; i < hvlen; i++) {
switch (state) {
case 0:
if (hvp[i] == 0) {
// skip 0 char
continue;
}
if (v_off == 0 && hvp[i] == ' ') {
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// skip leading space
continue;
}
if (tolower(hvp[i]) == tolower(value[v_off])) {
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v_off++;
if (value[v_off] == 0) {
// finish validation if end of token
state = 2;
}
continue;
} else {
// wait for a new token
v_off = 0;
state = 1;
}
// fallthrough
case 1:
if (hvp[i] == ',') {
// start of next token
state = 0;
}
break;
case 2:
if (hvp[i] == ',') {
return HTP_OK;
}
if (hvp[i] != 0 && hvp[i] != ' ') {
// trailing junk in token, cait for a next one
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v_off = 0;
state = 1;
}
}
}
if (state == 2) {
return HTP_OK;
}
return HTP_ERROR;
}
36 changes: 36 additions & 0 deletions test/test_utils.cpp
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Expand Up @@ -1801,3 +1801,39 @@ TEST_F(UrlencodedParser, UrlDecode1) {
ASSERT_EQ(0, bstr_cmp_c(s, "/one/two/three/%3"));
bstr_free(s);
}

TEST(UtilTest, HeaderHasToken) {
char data[100];

// Basic
strcpy(data, "chunked");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));

// Negative
strcpy(data, "notchunked");
EXPECT_EQ(HTP_ERROR, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunkednot");
EXPECT_EQ(HTP_ERROR, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunk,ed");
EXPECT_EQ(HTP_ERROR, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunk ed");
EXPECT_EQ(HTP_ERROR, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));

// Positive
strcpy(data, " notchunked , chunked , yetanother");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunked,yetanother");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "not,chunked");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunk,chunked");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, " chunked");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunked ");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, "chunked,");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
strcpy(data, ",chunked");
EXPECT_EQ(HTP_OK, htp_header_has_token((unsigned char*) data, strlen(data), (unsigned char *)"chunked"));
}