htdigest: Fix buffer overflow when reading digest

password file with very long lines.

PR 54893.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1475878 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index deca4432f0917678952224dd3a369cb153e20aaf..802385cafe6687dbf08f0be1a8853f3135bde089 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) htdigest: Fix buffer overflow when reading digest password file
+     with very long lines. PR 54893. [Rainer Jung]
+
   *) mod_setenvif: Fix crash in case SetEnvif and SetEnvIfExpr are used
      together. PR 54881. [Ruediger Pluem]
 

diff --git a/support/htdigest.c b/support/htdigest.c
index a8b464aedda3ca1ed6889de4fc18eda9621af640..f76036d7a5bd34e3e583d0f8e6027d2e7fe64482 100644 (file)
--- a/support/htdigest.c
+++ b/support/htdigest.c
@@ -96,12 +96,15 @@ static int get_line(char *s, int n, apr_file_t *f)
     char ch;
     apr_status_t rv = APR_EINVAL;
 
-    while (i < (n - 1) &&
+    /* we need 2 remaining bytes in buffer */
+    while (i < (n - 2) &&
            ((rv = apr_file_getc(&ch, f)) == APR_SUCCESS) && (ch != '\n')) {
         s[i++] = ch;
     }
+    /* First remaining byte potentially used here */
     if (ch == '\n')
         s[i++] = ch;
+    /* Second remaining byte used here */
     s[i] = '\0';
 
     if (rv != APR_SUCCESS)