Commit 0269f644 authored by Tatsuhiro Tsujikawa's avatar Tatsuhiro Tsujikawa Committed by Jay Satiro
Browse files

http2: Don't send header fields prohibited by HTTP/2 spec 

Previously, we just ignored "Connection" header field.  But HTTP/2
specification actually prohibits few more header fields.  This commit
ignores all of them so that we don't send these bad header fields.

Bug: https://curl.haxx.se/mail/archive-2016-10/0033.html
Reported-by: Ricki Hirner

Closes https://github.com/curl/curl/pull/1092
parent 677d8b3f

lib/http2.c

+85 −14
Original line number Diff line number Diff line
@@ -1572,6 +1572,71 @@ static ssize_t http2_recv(struct connectdata *conn, int sockindex, 
#define HEADER_OVERFLOW(x) \

  (x.namelen > (uint16_t)-1 || x.valuelen > (uint16_t)-1 - x.namelen)



/*

 * Check header memory for the token "trailers".

 * Parse the tokens as separated by comma and surrounded by whitespace.

 * Returns TRUE if found or FALSE if not.

 */

static bool contains_trailers(const char *p, size_t len) {

  const char *end = p + len;

  for(;;) {

    for(; p != end && (*p == ' ' || *p == '\t'); ++p)

      ;

    if(p == end || (size_t)(end - p) < sizeof("trailers") - 1)

      return FALSE;

    if(strncasecompare("trailers", p, sizeof("trailers") - 1)) {

      p += sizeof("trailers") - 1;

      for(; p != end && (*p == ' ' || *p == '\t'); ++p)

        ;

      if(p == end || *p == ',')

        return TRUE;

    }

    /* skip to next token */

    for(; p != end && *p != ','; ++p)

      ;

    if(p == end)

      return FALSE;

    ++p;

  }

}



typedef enum {

  /* Send header to server */

  HEADERINST_FORWARD,

  /* Don't send header to server */

  HEADERINST_IGNORE,

  /* Discard header, and replace it with "te: trailers" */

  HEADERINST_TE_TRAILERS

} header_instruction;



/* Decides how to treat given header field. */

static header_instruction inspect_header(const char *name, size_t namelen,

                                         const char *value, size_t valuelen) {

  switch(namelen) {

  case 2:

    if(!strncasecompare("te", name, namelen))

      return HEADERINST_FORWARD;



    return contains_trailers(value, valuelen) ?

           HEADERINST_TE_TRAILERS : HEADERINST_IGNORE;

  case 7:

    return strncasecompare("upgrade", name, namelen) ?

           HEADERINST_IGNORE : HEADERINST_FORWARD;

  case 10:

    return (strncasecompare("connection", name, namelen) ||

            strncasecompare("keep-alive", name, namelen)) ?

           HEADERINST_IGNORE : HEADERINST_FORWARD;

  case 16:

    return strncasecompare("proxy-connection", name, namelen) ?

           HEADERINST_IGNORE : HEADERINST_FORWARD;

  case 17:

    return strncasecompare("transfer-encoding", name, namelen) ?

           HEADERINST_IGNORE : HEADERINST_FORWARD;

  default:

    return HEADERINST_FORWARD;

  }

}



static ssize_t http2_send(struct connectdata *conn, int sockindex,

                          const void *mem, size_t len, CURLcode *err)

{
@@ -1725,7 +1790,6 @@ static ssize_t http2_send(struct connectdata *conn, int sockindex, 
  i = 3;

  while(i < nheader) {

    size_t hlen;

    int skip = 0;



    hdbuf = line_end + 2;
@@ -1743,12 +1807,7 @@ static ssize_t http2_send(struct connectdata *conn, int sockindex, 
      goto fail;

    hlen = end - hdbuf;



    if(hlen == 10 && strncasecompare("connection", hdbuf, 10)) {

      /* skip Connection: headers! */

      skip = 1;

      --nheader;

    }

    else if(hlen == 4 && strncasecompare("host", hdbuf, 4)) {

    if(hlen == 4 && strncasecompare("host", hdbuf, 4)) {

      authority_idx = i;

      nva[i].name = (unsigned char *)":authority";

      nva[i].namelen = strlen((char *)nva[i].name);
@@ -1761,9 +1820,22 @@ static ssize_t http2_send(struct connectdata *conn, int sockindex, 
    while(*hdbuf == ' ' || *hdbuf == '\t')

      ++hdbuf;

    end = line_end;

    if(!skip) {



    switch(inspect_header((const char *)nva[i].name, nva[i].namelen, hdbuf,

                          end - hdbuf)) {

    case HEADERINST_IGNORE:

      /* skip header fields prohibited by HTTP/2 specification. */

      --nheader;

      continue;

    case HEADERINST_TE_TRAILERS:

      nva[i].value = (uint8_t*)"trailers";

      nva[i].valuelen = sizeof("trailers") - 1;

      break;

    default:

      nva[i].value = (unsigned char *)hdbuf;

      nva[i].valuelen = (size_t)(end - hdbuf);

    }



    nva[i].flags = NGHTTP2_NV_FLAG_NONE;

    if(HEADER_OVERFLOW(nva[i])) {

      failf(conn->data, "Failed sending HTTP request: Header overflow");
@@ -1771,7 +1843,6 @@ static ssize_t http2_send(struct connectdata *conn, int sockindex, 
    }

    ++i;

  }

  }



  /* :authority must come before non-pseudo header fields */

  if(authority_idx != 0 && authority_idx != AUTHORITY_DST_IDX) {