ext_password_file: Do not use wpa_config_get_line()

The file-based backed of the ext_password framework uses
wpa_config_get_line() to read the passwords line-by-line from a file.
This function is meant to parse a single line from the
wpa_supplicant.conf file, so it handles whitespace, quotes and other
characters specially.

Its behavior, however, it's not compatible with the rest of the
ext_password framework implementation. For example, if a passphrase
contains a `#` character it must be quoted to prevent parsing the
remaining characters as an inline comment, but the code handling the
external password in wpa_supplicant_get_psk() does not handle quotes.
The result is that either it will hash the enclosing quotes, producing a
wrong PSK, or if the passphrase is long enough, fail the length check.
As a consequence, some passphrases are impossible to input correctly.

To solve this and other issues, this patch changes the behaviour of the
ext_password_file_get() function (which was not documented in details,
at least w.r.t. special characters) to simply treat all characters
literally: including trailing whitespaces (except CR and LF), `#` for
inline comments, etc. Empty lines and full-line comments are still
supported.

Signed-off-by: Michele Guerini Rocco <rnhmjoj@inventati.org>

diff --git a/src/utils/ext_password_file.c b/src/utils/ext_password_file.c
index 4bb0095f3f28ac87728d66e65e1179d85b5db7c0..312251263ad1ec2c281c2c9d16a9413624bdaea0 100644 (file)
--- a/src/utils/ext_password_file.c
+++ b/src/utils/ext_password_file.c
@@ -9,7 +9,6 @@
 #include "includes.h"
 
 #include "utils/common.h"
-#include "utils/config.h"
 #include "ext_password_i.h"
 
 
@@ -97,9 +96,19 @@ static struct wpabuf * ext_password_file_get(void *ctx, const char *name)
 
        wpa_printf(MSG_DEBUG, "EXT PW FILE: get(%s)", name);
 
-       while (wpa_config_get_line(buf, sizeof(buf), f, &line, &pos)) {
-               char *sep = os_strchr(pos, '=');
+       while ((pos = fgets(buf, sizeof(buf), f))) {
+               char *sep;
 
+               line++;
+
+               /* Strip newline characters */
+               pos[strcspn(pos, "\r\n")] = 0;
+
+               /* Skip comments and empty lines */
+               if (*pos == '#' || *pos == '\0')
+                       continue;
+
+               sep = os_strchr(pos, '=');
                if (!sep) {
                        wpa_printf(MSG_ERROR, "Invalid password line %d.",
                                   line);