[PATCH v2 0/2] block/curl: Improve HTTP header parsing

[PATCH v2 0/2] block/curl: Improve HTTP header parsing

[David Edmondson]

An HTTP object store of my acquaintance returns "accept-ranges: bytes"
(all lower case) as a header, causing the QEMU curl backend to refuse
to talk to it. RFC 7230 says that HTTP headers are case insensitive,
so update the curl backend accordingly.

At the same time, allow for arbitrary white space around the HTTP
header field value, as required by the RFC.

v2:
- strncasecmp -> g_ascii_strncasecmp (Philippe).
- isspace -> g_ascii_isspace, for good measure.

David Edmondson (2):
  block/curl: HTTP header fields allow whitespace around values
  block/curl: HTTP header field names are case insensitive

 block/curl.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

-- 
2.24.1

[PATCH v2 1/2] block/curl: HTTP header fields allow whitespace around values

[David Edmondson]

RFC 7230 section 3.2 indicates that whitespace is permitted between
the field name and field value and after the field value.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
---
 block/curl.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index f86299378e38..f9ffb7f4e2bf 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -214,11 +214,34 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 {
     BDRVCURLState *s = opaque;
     size_t realsize = size * nmemb;
-    const char *accept_line = "Accept-Ranges: bytes";
+    const char *header = (char *)ptr;
+    const char *end = header + realsize;
+    const char *accept_ranges = "Accept-Ranges:";
+    const char *bytes = "bytes";
 
-    if (realsize >= strlen(accept_line)
-        && strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
-        s->accept_range = true;
+    if (realsize >= strlen(accept_ranges)
+        && strncmp(header, accept_ranges, strlen(accept_ranges)) == 0) {
+
+        char *p = strchr(header, ':') + 1;
+
+        /* Skip whitespace between the header name and value. */
+        while (p < end && *p && g_ascii_isspace(*p)) {
+            p++;
+        }
+
+        if (end - p >= strlen(bytes)
+            && strncmp(p, bytes, strlen(bytes)) == 0) {
+
+            /* Check that there is nothing but whitespace after the value. */
+            p += strlen(bytes);
+            while (p < end && *p && g_ascii_isspace(*p)) {
+                p++;
+            }
+
+            if (p == end || !*p) {
+                s->accept_range = true;
+            }
+        }
     }
 
     return realsize;
-- 
2.24.1

[PATCH v2 2/2] block/curl: HTTP header field names are case insensitive

[David Edmondson]

RFC 7230 section 3.2 indicates that HTTP header field names are case
insensitive.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
---
 block/curl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index f9ffb7f4e2bf..1421e8fb9815 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -216,11 +216,11 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
     size_t realsize = size * nmemb;
     const char *header = (char *)ptr;
     const char *end = header + realsize;
-    const char *accept_ranges = "Accept-Ranges:";
+    const char *accept_ranges = "accept-ranges:";
     const char *bytes = "bytes";
 
     if (realsize >= strlen(accept_ranges)
-        && strncmp(header, accept_ranges, strlen(accept_ranges)) == 0) {
+        && g_ascii_strncasecmp(header, accept_ranges, strlen(accept_ranges)) == 0) {
 
         char *p = strchr(header, ':') + 1;
 
-- 
2.24.1