--- /dev/null
+From a9bd3dec9fde03327a4a2c69dad1036bf9632e20 Mon Sep 17 00:00:00 2001
+From: Chris Liddell <chris.liddell@artifex.com>
+Date: Tue, 7 Sep 2021 20:36:12 +0100
+Subject: [PATCH] Bug 704342: Include device specifier strings in access
+ validation
+
+for the "%pipe%", %handle%" and %printer% io devices.
+
+We previously validated only the part after the "%pipe%" Postscript device
+specifier, but this proved insufficient.
+
+This rebuilds the original file name string, and validates it complete. The
+slight complication for "%pipe%" is it can be reached implicitly using
+"|" so we have to check both prefixes.
+
+Addresses CVE-2021-3781
+
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ base/gdevpipe.c | 22 +++++++++++++++-
+ base/gp_mshdl.c | 11 +++++++-
+ base/gp_msprn.c | 10 ++++++-
+ base/gp_os2pr.c | 13 +++++++++-
+ base/gslibctx.c | 69 ++++++++++---------------------------------------
+ 5 files changed, 65 insertions(+), 60 deletions(-)
+
+diff --git a/base/gdevpipe.c b/base/gdevpipe.c
+index 96d71f5d8..5bdc485be 100644
+--- a/base/gdevpipe.c
++++ b/base/gdevpipe.c
+@@ -72,8 +72,28 @@ pipe_fopen(gx_io_device * iodev, const char *fname, const char *access,
+ #else
+ gs_lib_ctx_t *ctx = mem->gs_lib_ctx;
+ gs_fs_list_t *fs = ctx->core->fs;
++ /* The pipe device can be reached in two ways, explicltly with %pipe%
++ or implicitly with "|", so we have to check for both
++ */
++ char f[gp_file_name_sizeof];
++ const char *pipestr = "|";
++ const size_t pipestrlen = strlen(pipestr);
++ const size_t preflen = strlen(iodev->dname);
++ const size_t nlen = strlen(fname);
++ int code1;
++
++ if (preflen + nlen >= gp_file_name_sizeof)
++ return_error(gs_error_invalidaccess);
++
++ memcpy(f, iodev->dname, preflen);
++ memcpy(f + preflen, fname, nlen + 1);
++
++ code1 = gp_validate_path(mem, f, access);
++
++ memcpy(f, pipestr, pipestrlen);
++ memcpy(f + pipestrlen, fname, nlen + 1);
+
+- if (gp_validate_path(mem, fname, access) != 0)
++ if (code1 != 0 && gp_validate_path(mem, f, access) != 0 )
+ return gs_error_invalidfileaccess;
+
+ /*
+diff --git a/base/gp_mshdl.c b/base/gp_mshdl.c
+index 2b964ed74..8d87ceadc 100644
+--- a/base/gp_mshdl.c
++++ b/base/gp_mshdl.c
+@@ -95,8 +95,17 @@ mswin_handle_fopen(gx_io_device * iodev, const char *fname, const char *access,
+ long hfile; /* Correct for Win32, may be wrong for Win64 */
+ gs_lib_ctx_t *ctx = mem->gs_lib_ctx;
+ gs_fs_list_t *fs = ctx->core->fs;
++ char f[gp_file_name_sizeof];
++ const size_t preflen = strlen(iodev->dname);
++ const size_t nlen = strlen(fname);
+
+- if (gp_validate_path(mem, fname, access) != 0)
++ if (preflen + nlen >= gp_file_name_sizeof)
++ return_error(gs_error_invalidaccess);
++
++ memcpy(f, iodev->dname, preflen);
++ memcpy(f + preflen, fname, nlen + 1);
++
++ if (gp_validate_path(mem, f, access) != 0)
+ return gs_error_invalidfileaccess;
+
+ /* First we try the open_handle method. */
+diff --git a/base/gp_msprn.c b/base/gp_msprn.c
+index ed4827968..746a974f7 100644
+--- a/base/gp_msprn.c
++++ b/base/gp_msprn.c
+@@ -168,8 +168,16 @@ mswin_printer_fopen(gx_io_device * iodev, const char *fname, const char *access,
+ uintptr_t *ptid = &((tid_t *)(iodev->state))->tid;
+ gs_lib_ctx_t *ctx = mem->gs_lib_ctx;
+ gs_fs_list_t *fs = ctx->core->fs;
++ const size_t preflen = strlen(iodev->dname);
++ const size_t nlen = strlen(fname);
+
+- if (gp_validate_path(mem, fname, access) != 0)
++ if (preflen + nlen >= gp_file_name_sizeof)
++ return_error(gs_error_invalidaccess);
++
++ memcpy(pname, iodev->dname, preflen);
++ memcpy(pname + preflen, fname, nlen + 1);
++
++ if (gp_validate_path(mem, pname, access) != 0)
+ return gs_error_invalidfileaccess;
+
+ /* First we try the open_printer method. */
+diff --git a/base/gp_os2pr.c b/base/gp_os2pr.c
+index f852c71fc..ba54cde66 100644
+--- a/base/gp_os2pr.c
++++ b/base/gp_os2pr.c
+@@ -107,9 +107,20 @@ os2_printer_fopen(gx_io_device * iodev, const char *fname, const char *access,
+ FILE ** pfile, char *rfname, uint rnamelen)
+ {
+ os2_printer_t *pr = (os2_printer_t *)iodev->state;
+- char driver_name[256];
++ char driver_name[gp_file_name_sizeof];
+ gs_lib_ctx_t *ctx = mem->gs_lib_ctx;
+ gs_fs_list_t *fs = ctx->core->fs;
++ const size_t preflen = strlen(iodev->dname);
++ const int size_t = strlen(fname);
++
++ if (preflen + nlen >= gp_file_name_sizeof)
++ return_error(gs_error_invalidaccess);
++
++ memcpy(driver_name, iodev->dname, preflen);
++ memcpy(driver_name + preflen, fname, nlen + 1);
++
++ if (gp_validate_path(mem, driver_name, access) != 0)
++ return gs_error_invalidfileaccess;
+
+ /* First we try the open_printer method. */
+ /* Note that the loop condition here ensures we don't
+diff --git a/base/gslibctx.c b/base/gslibctx.c
+index 6dfed6cd5..318039fad 100644
+--- a/base/gslibctx.c
++++ b/base/gslibctx.c
+@@ -655,82 +655,39 @@ rewrite_percent_specifiers(char *s)
+ int
+ gs_add_outputfile_control_path(gs_memory_t *mem, const char *fname)
+ {
+- char *fp, f[gp_file_name_sizeof];
+- const int pipe = 124; /* ASCII code for '|' */
+- const int len = strlen(fname);
+- int i, code;
++ char f[gp_file_name_sizeof];
++ int code;
+
+ /* Be sure the string copy will fit */
+- if (len >= gp_file_name_sizeof)
++ if (strlen(fname) >= gp_file_name_sizeof)
+ return gs_error_rangecheck;
+ strcpy(f, fname);
+- fp = f;
+ /* Try to rewrite any %d (or similar) in the string */
+ rewrite_percent_specifiers(f);
+- for (i = 0; i < len; i++) {
+- if (f[i] == pipe) {
+- fp = &f[i + 1];
+- /* Because we potentially have to check file permissions at two levels
+- for the output file (gx_device_open_output_file and the low level
+- fopen API, if we're using a pipe, we have to add both the full string,
+- (including the '|', and just the command to which we pipe - since at
+- the pipe_fopen(), the leading '|' has been stripped.
+- */
+- code = gs_add_control_path(mem, gs_permit_file_writing, f);
+- if (code < 0)
+- return code;
+- code = gs_add_control_path(mem, gs_permit_file_control, f);
+- if (code < 0)
+- return code;
+- break;
+- }
+- if (!IS_WHITESPACE(f[i]))
+- break;
+- }
+- code = gs_add_control_path(mem, gs_permit_file_control, fp);
++
++ code = gs_add_control_path(mem, gs_permit_file_control, f);
+ if (code < 0)
+ return code;
+- return gs_add_control_path(mem, gs_permit_file_writing, fp);
++ return gs_add_control_path(mem, gs_permit_file_writing, f);
+ }
+
+ int
+ gs_remove_outputfile_control_path(gs_memory_t *mem, const char *fname)
+ {
+- char *fp, f[gp_file_name_sizeof];
+- const int pipe = 124; /* ASCII code for '|' */
+- const int len = strlen(fname);
+- int i, code;
++ char f[gp_file_name_sizeof];
++ int code;
+
+ /* Be sure the string copy will fit */
+- if (len >= gp_file_name_sizeof)
++ if (strlen(fname) >= gp_file_name_sizeof)
+ return gs_error_rangecheck;
+ strcpy(f, fname);
+- fp = f;
+ /* Try to rewrite any %d (or similar) in the string */
+- for (i = 0; i < len; i++) {
+- if (f[i] == pipe) {
+- fp = &f[i + 1];
+- /* Because we potentially have to check file permissions at two levels
+- for the output file (gx_device_open_output_file and the low level
+- fopen API, if we're using a pipe, we have to add both the full string,
+- (including the '|', and just the command to which we pipe - since at
+- the pipe_fopen(), the leading '|' has been stripped.
+- */
+- code = gs_remove_control_path(mem, gs_permit_file_writing, f);
+- if (code < 0)
+- return code;
+- code = gs_remove_control_path(mem, gs_permit_file_control, f);
+- if (code < 0)
+- return code;
+- break;
+- }
+- if (!IS_WHITESPACE(f[i]))
+- break;
+- }
+- code = gs_remove_control_path(mem, gs_permit_file_control, fp);
++ rewrite_percent_specifiers(f);
++
++ code = gs_remove_control_path(mem, gs_permit_file_control, f);
+ if (code < 0)
+ return code;
+- return gs_remove_control_path(mem, gs_permit_file_writing, fp);
++ return gs_remove_control_path(mem, gs_permit_file_writing, f);
+ }
+
+ int
+--
+2.20.1
+
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