125 lines
3.8 KiB
Diff
125 lines
3.8 KiB
Diff
From 291b47380b2e0dd7c526bbde8d82ae6d739ef266 Mon Sep 17 00:00:00 2001
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From: Philip Withnall <pwithnall@gnome.org>
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Date: Thu, 13 Nov 2025 18:27:22 +0000
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Subject: [PATCH] gconvert: Error out if g_escape_uri_string() would overflow
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If the string to escape contains a very large number of unacceptable
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characters (which would need escaping), the calculation of the length of
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the escaped string could overflow, leading to a potential write off the
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end of the newly allocated string.
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In addition to that, the number of unacceptable characters was counted
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in a signed integer, which would overflow to become negative, making it
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easier for an attacker to craft an input string which would cause an
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out-of-bounds write.
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Fix that by validating the allocation length, and using an unsigned
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integer to count the number of unacceptable characters.
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Spotted by treeplus. Thanks to the Sovereign Tech Resilience programme
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from the Sovereign Tech Agency. ID: #YWH-PGM9867-134
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Signed-off-by: Philip Withnall <pwithnall@gnome.org>
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Fixes: #3827
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---
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glib/gconvert.c | 36 +++++++++++++++++++++++++-----------
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1 file changed, 25 insertions(+), 11 deletions(-)
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diff --git a/glib/gconvert.c b/glib/gconvert.c
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index e7c222f8d..ffd860a83 100644
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--- a/glib/gconvert.c
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+++ b/glib/gconvert.c
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@@ -1338,8 +1338,9 @@ static const gchar hex[] = "0123456789ABCDEF";
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/* Note: This escape function works on file: URIs, but if you want to
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* escape something else, please read RFC-2396 */
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static gchar *
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-g_escape_uri_string (const gchar *string,
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- UnsafeCharacterSet mask)
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+g_escape_uri_string (const gchar *string,
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+ UnsafeCharacterSet mask,
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+ GError **error)
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{
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#define ACCEPTABLE(a) ((a)>=32 && (a)<128 && (acceptable[(a)-32] & use_mask))
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@@ -1347,7 +1348,7 @@ g_escape_uri_string (const gchar *string,
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gchar *q;
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gchar *result;
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int c;
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- gint unacceptable;
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+ size_t unacceptable;
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UnsafeCharacterSet use_mask;
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g_return_val_if_fail (mask == UNSAFE_ALL
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@@ -1364,7 +1365,14 @@ g_escape_uri_string (const gchar *string,
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if (!ACCEPTABLE (c))
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unacceptable++;
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}
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-
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+
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+ if (unacceptable >= (G_MAXSIZE - (p - string)) / 2)
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+ {
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+ g_set_error_literal (error, G_CONVERT_ERROR, G_CONVERT_ERROR_BAD_URI,
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+ _("The URI is too long"));
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+ return NULL;
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+ }
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+
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result = g_malloc (p - string + unacceptable * 2 + 1);
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use_mask = mask;
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@@ -1389,12 +1397,13 @@ g_escape_uri_string (const gchar *string,
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static gchar *
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-g_escape_file_uri (const gchar *hostname,
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- const gchar *pathname)
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+g_escape_file_uri (const gchar *hostname,
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+ const gchar *pathname,
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+ GError **error)
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{
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char *escaped_hostname = NULL;
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- char *escaped_path;
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- char *res;
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+ char *escaped_path = NULL;
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+ char *res = NULL;
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#ifdef G_OS_WIN32
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char *p, *backslash;
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@@ -1415,10 +1424,14 @@ g_escape_file_uri (const gchar *hostname,
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if (hostname && *hostname != '\0')
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{
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- escaped_hostname = g_escape_uri_string (hostname, UNSAFE_HOST);
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+ escaped_hostname = g_escape_uri_string (hostname, UNSAFE_HOST, error);
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+ if (escaped_hostname == NULL)
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+ goto out;
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}
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- escaped_path = g_escape_uri_string (pathname, UNSAFE_PATH);
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+ escaped_path = g_escape_uri_string (pathname, UNSAFE_PATH, error);
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+ if (escaped_path == NULL)
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+ goto out;
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res = g_strconcat ("file://",
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(escaped_hostname) ? escaped_hostname : "",
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@@ -1426,6 +1439,7 @@ g_escape_file_uri (const gchar *hostname,
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escaped_path,
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NULL);
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+out:
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#ifdef G_OS_WIN32
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g_free ((char *) pathname);
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#endif
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@@ -1759,7 +1773,7 @@ g_filename_to_uri (const gchar *filename,
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hostname = NULL;
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#endif
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- escaped_uri = g_escape_file_uri (hostname, filename);
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+ escaped_uri = g_escape_file_uri (hostname, filename, error);
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return escaped_uri;
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}
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--
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2.52.0
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