From b26b4c08e7119281ff30d0fb4a6169bd2afa8fe4 Mon Sep 17 00:00:00 2001 From: Daniel Axtens 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 Reviewed-by: Daniel Kiper --- 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