From ed607fedbcd41f4a0e71df6af4ba5b07dd630209 Mon Sep 17 00:00:00 2001
From: Chris Liddell <chris.liddell@artifex.com>
Date: Wed, 7 Jun 2023 10:23:06 +0100
Subject: [PATCH 1/2] Bug 706761: Don't "reduce" %pipe% file names for
 permission validation

For regular file names, we try to simplfy relative paths before we use them.

Because the %pipe% device can, effectively, accept command line calls, we
shouldn't be simplifying that string, because the command line syntax can end
up confusing the path simplifying code. That can result in permitting a pipe
command which does not match what was originally permitted.

Special case "%pipe" in the validation code so we always deal with the entire
string.

Upstream-Status: Backport [https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=5e65eeae225c7d02d447de5abaf4a8e6d234fcea]
CVE: CVE-2023-36664

Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
---
 base/gpmisc.c   | 31 +++++++++++++++++++--------
 base/gslibctx.c | 56 ++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 64 insertions(+), 23 deletions(-)

diff --git a/base/gpmisc.c b/base/gpmisc.c
index 8b6458a..c61ab3f 100644
--- a/base/gpmisc.c
+++ b/base/gpmisc.c
@@ -1076,16 +1076,29 @@ gp_validate_path_len(const gs_memory_t *mem,
              && !memcmp(path + cdirstrl, dirsepstr, dirsepstrl)) {
           prefix_len = 0;
     }
-    rlen = len+1;
-    bufferfull = (char *)gs_alloc_bytes(mem->thread_safe_memory, rlen + prefix_len, "gp_validate_path");
-    if (bufferfull == NULL)
-        return gs_error_VMerror;
-
-    buffer = bufferfull + prefix_len;
-    if (gp_file_name_reduce(path, (uint)len, buffer, &rlen) != gp_combine_success)
-        return gs_error_invalidfileaccess;
-    buffer[rlen] = 0;

+    /* "%pipe%" do not follow the normal rules for path definitions, so we
+       don't "reduce" them to avoid unexpected results
+     */
+    if (len > 5 && memcmp(path, "%pipe", 5) != 0) {
+        bufferfull = buffer = (char *)gs_alloc_bytes(mem->thread_safe_memory, len + 1, "gp_validate_path");
+        if (buffer == NULL)
+            return gs_error_VMerror;
+        memcpy(buffer, path, len);
+        buffer[len] = 0;
+        rlen = len;
+    }
+    else {
+        rlen = len+1;
+        bufferfull = (char *)gs_alloc_bytes(mem->thread_safe_memory, rlen + prefix_len, "gp_validate_path");
+        if (bufferfull == NULL)
+            return gs_error_VMerror;
+
+        buffer = bufferfull + prefix_len;
+        if (gp_file_name_reduce(path, (uint)len, buffer, &rlen) != gp_combine_success)
+            return gs_error_invalidfileaccess;
+        buffer[rlen] = 0;
+    }
     while (1) {
         switch (mode[0])
         {
diff --git a/base/gslibctx.c b/base/gslibctx.c
index 5bf497b..5fdfe25 100644
--- a/base/gslibctx.c
+++ b/base/gslibctx.c
@@ -734,14 +734,28 @@ gs_add_control_path_len_flags(const gs_memory_t *mem, gs_path_control_t type, co
             return gs_error_rangecheck;
     }

-    rlen = len+1;
-    buffer = (char *)gs_alloc_bytes(core->memory, rlen, "gp_validate_path");
-    if (buffer == NULL)
-        return gs_error_VMerror;
+    /* "%pipe%" do not follow the normal rules for path definitions, so we
+       don't "reduce" them to avoid unexpected results
+     */
+    if (len > 5 && memcmp(path, "%pipe", 5) != 0) {
+        buffer = (char *)gs_alloc_bytes(core->memory, len + 1, "gs_add_control_path_len");
+        if (buffer == NULL)
+            return gs_error_VMerror;
+        memcpy(buffer, path, len);
+        buffer[len] = 0;
+        rlen = len;
+    }
+    else {
+        rlen = len + 1;

-    if (gp_file_name_reduce(path, (uint)len, buffer, &rlen) != gp_combine_success)
-        return gs_error_invalidfileaccess;
-    buffer[rlen] = 0;
+        buffer = (char *)gs_alloc_bytes(core->memory, rlen, "gs_add_control_path_len");
+        if (buffer == NULL)
+            return gs_error_VMerror;
+
+        if (gp_file_name_reduce(path, (uint)len, buffer, &rlen) != gp_combine_success)
+            return gs_error_invalidfileaccess;
+        buffer[rlen] = 0;
+    }

     n = control->num;
     for (i = 0; i < n; i++)
@@ -827,14 +841,28 @@ gs_remove_control_path_len_flags(const gs_memory_t *mem, gs_path_control_t type,
             return gs_error_rangecheck;
     }

-    rlen = len+1;
-    buffer = (char *)gs_alloc_bytes(core->memory, rlen, "gp_validate_path");
-    if (buffer == NULL)
-        return gs_error_VMerror;
+    /* "%pipe%" do not follow the normal rules for path definitions, so we
+       don't "reduce" them to avoid unexpected results
+     */
+    if (len > 5 && memcmp(path, "%pipe", 5) != 0) {
+        buffer = (char *)gs_alloc_bytes(core->memory, len + 1, "gs_remove_control_path_len");
+        if (buffer == NULL)
+            return gs_error_VMerror;
+        memcpy(buffer, path, len);
+        buffer[len] = 0;
+        rlen = len;
+    }
+    else {
+        rlen = len+1;

-    if (gp_file_name_reduce(path, (uint)len, buffer, &rlen) != gp_combine_success)
-        return gs_error_invalidfileaccess;
-    buffer[rlen] = 0;
+        buffer = (char *)gs_alloc_bytes(core->memory, rlen, "gs_remove_control_path_len");
+        if (buffer == NULL)
+            return gs_error_VMerror;
+
+        if (gp_file_name_reduce(path, (uint)len, buffer, &rlen) != gp_combine_success)
+            return gs_error_invalidfileaccess;
+        buffer[rlen] = 0;
+    }

     n = control->num;
     for (i = 0; i < n; i++) {
--
2.40.1
