From b26b4c08e7119281ff30d0fb4a6169bd2afa8fe4 Mon Sep 17 00:00:00 2001

From: Daniel Axtens <dja@axtens.net>

Date: Tue, 8 Mar 2022 19:04:40 +1100

Subject: [PATCH 8/8] net/http: Error out on headers with LF without CR

In a similar vein to the previous patch, parse_line() would write

a NUL byte past the end of the buffer if there was an HTTP header

with a LF rather than a CRLF.

RFC-2616 says:

  Many HTTP/1.1 header field values consist of words separated by LWS

  or special characters. These special characters MUST be in a quoted

  string to be used within a parameter value (as defined in section 3.6).

We don't support quoted sections or continuation lines, etc.

If we see an LF that's not part of a CRLF, bail out.

Fixes: CVE-2022-28734

Signed-off-by: Daniel Axtens <dja@axtens.net>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

---

 grub-core/net/http.c | 8 ++++++++

 1 file changed, 8 insertions(+)

diff --git a/grub-core/net/http.c b/grub-core/net/http.c

index 33a0a28c4..9291a13e2 100644

--- a/grub-core/net/http.c

+++ b/grub-core/net/http.c

@@ -68,7 +68,15 @@ parse_line (grub_file_t file, http_data_t data, char *ptr, grub_size_t len)

   char *end = ptr + len;

   while (end > ptr && *(end - 1) == '\r')

     end--;

+

+  /* LF without CR. */

+  if (end == ptr + len)

+    {

+      data->errmsg = grub_strdup (_("invalid HTTP header - LF without CR"));

+      return GRUB_ERR_NONE;

+    }

   *end = 0;

+

   /* Trailing CRLF.  */

   if (data->in_chunk_len == 1)

     {

-- 

2.33.5