wget: do not abort if "_" is encountered in a HTTP header

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/networking/wget.c b/networking/wget.c
index 4eafebe40..ce2f51411 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -328,8 +328,16 @@ static char *gethdr(FILE *fp)
                 return NULL;
 
         /* convert the header name to lower case */
-        for (s = G.wget_buf; isalnum(*s) || *s == '-' || *s == '.'; ++s) {
-                /* tolower for "A-Z", no-op for "0-9a-z-." */
+        for (s = G.wget_buf; isalnum(*s) || *s == '-' || *s == '.' || *s == '_'; ++s) {
+                /*
+                 * No-op for 20-3f and 60-7f. "0-9a-z-." are in these ranges.
+                 * 40-5f range ("@A-Z[\]^_") maps to 60-7f.
+                 * "A-Z" maps to "a-z".
+                 * "@[\]" can't occur in header names.
+                 * "^_" maps to "~,DEL" (which is wrong).
+                 * "^" was never seen yet, "_" was seen from web.archive.org
+                 * (x-archive-orig-x_commoncrawl_Signature: HEXSTRING).
+                 */
                 *s |= 0x20;
         }