The following patch was adapted for GNU Ghostscript by Mark H Weaver based on: http://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=6d444c273da5499a4cd72f21cb6d4c9a5256807d From 6d444c273da5499a4cd72f21cb6d4c9a5256807d Mon Sep 17 00:00:00 2001 From: Chris Liddell Date: Wed, 5 Oct 2016 09:55:55 +0100 Subject: [PATCH] Bug 697178: Add a file permissions callback For the rare occasions when the graphics library directly opens a file (currently for reading), this allows us to apply any restrictions on file access normally applied in the interpteter. --- base/gsicc_manage.c | 10 ++++++---- base/gslibctx.c | 12 +++++++++++- base/gslibctx.h | 7 +++++++ psi/imain.c | 2 ++ psi/int.mak | 2 +- psi/zfile.c | 19 +++++++++++++++++++ psi/zfile.h | 7 +++++++ 7 files changed, 53 insertions(+), 6 deletions(-) diff --git a/base/gsicc_manage.c b/base/gsicc_manage.c index 931c2a6..e9c09c3 100644 --- a/base/gsicc_manage.c +++ b/base/gsicc_manage.c @@ -1028,10 +1028,12 @@ gsicc_open_search(const char* pname, int namelen, gs_memory_t *mem_gc, } /* First just try it like it is */ - str = sfopen(pname, "rb", mem_gc); - if (str != NULL) { - *strp = str; - return 0; + if (gs_check_file_permission(mem_gc, pname, namelen, "r") >= 0) { + str = sfopen(pname, "rb", mem_gc); + if (str != NULL) { + *strp = str; + return 0; + } } /* If that fails, try %rom% */ /* FIXME: Not sure this is needed or correct */ diff --git a/base/gslibctx.c b/base/gslibctx.c index eaa0458..37ce1ca 100644 --- a/base/gslibctx.c +++ b/base/gslibctx.c @@ -121,7 +121,7 @@ int gs_lib_ctx_init( gs_memory_t *mem ) mem->gs_lib_ctx = NULL; return -1; } - + pio->client_check_file_permission = NULL; gp_get_realtime(pio->real_time_0); return 0; @@ -262,3 +262,13 @@ void errflush(const gs_memory_t *mem) fflush(mem->gs_lib_ctx->fstderr); /* else nothing to flush */ } + +int +gs_check_file_permission (gs_memory_t *mem, const char *fname, const int len, const char *permission) +{ + int code = 0; + if (mem->gs_lib_ctx->client_check_file_permission != NULL) { + code = mem->gs_lib_ctx->client_check_file_permission(mem, fname, len, permission); + } + return code; +} diff --git a/base/gslibctx.h b/base/gslibctx.h index 7a4e110..020e2d9 100644 --- a/base/gslibctx.h +++ b/base/gslibctx.h @@ -32,6 +32,9 @@ typedef struct gs_fapi_server_s gs_fapi_server; # define gs_font_dir_DEFINED typedef struct gs_font_dir_s gs_font_dir; #endif + +typedef int (*client_check_file_permission_t) (gs_memory_t *mem, const char *fname, const int len, const char *permission); + typedef struct gs_lib_ctx_s { gs_memory_t *memory; /* mem->gs_lib_ctx->memory == mem */ @@ -59,6 +62,7 @@ typedef struct gs_lib_ctx_s bool dict_auto_expand; /* ps dictionary: false level 1 true level 2 or 3 */ /* A table of local copies of the IODevices */ struct gx_io_device_s **io_device_table; + client_check_file_permission_t client_check_file_permission; /* Define the default value of AccurateScreens that affects setscreen and setcolorscreen. */ bool screen_accurate_screens; @@ -108,6 +112,9 @@ int void gs_lib_ctx_set_icc_directory(const gs_memory_t *mem_gc, const char* pname, int dir_namelen); +int +gs_check_file_permission (gs_memory_t *mem, const char *fname, const int len, const char *permission); + #define IS_LIBCTX_STDOUT(mem, f) (f == mem->gs_lib_ctx->fstdout) #define IS_LIBCTX_STDERR(mem, f) (f == mem->gs_lib_ctx->fstderr) diff --git a/psi/imain.c b/psi/imain.c index 9a9bb5d..6874128 100644 --- a/psi/imain.c +++ b/psi/imain.c @@ -57,6 +57,7 @@ #include "ivmspace.h" #include "idisp.h" /* for setting display device callback */ #include "iplugin.h" +#include "zfile.h" #ifdef PACIFY_VALGRIND #include "valgrind.h" @@ -215,6 +216,7 @@ gs_main_init1(gs_main_instance * minst) "the_gs_name_table"); if (code < 0) return code; + mem->gs_lib_ctx->client_check_file_permission = z_check_file_permissions; } code = obj_init(&minst->i_ctx_p, &idmem); /* requires name_init */ if (code < 0) diff --git a/psi/int.mak b/psi/int.mak index 4654afc..bb30d51 100644 --- a/psi/int.mak +++ b/psi/int.mak @@ -1868,7 +1868,7 @@ $(PSOBJ)imain.$(OBJ) : $(PSSRC)imain.c $(GH) $(memory__h) $(string__h)\ $(ialloc_h) $(iconf_h) $(idebug_h) $(idict_h) $(idisp_h) $(iinit_h)\ $(iname_h) $(interp_h) $(iplugin_h) $(isave_h) $(iscan_h) $(ivmspace_h)\ $(iinit_h) $(main_h) $(oper_h) $(ostack_h)\ - $(sfilter_h) $(store_h) $(stream_h) $(strimpl_h) + $(sfilter_h) $(store_h) $(stream_h) $(strimpl_h) $(zfile_h) $(PSCC) $(PSO_)imain.$(OBJ) $(C_) $(PSSRC)imain.c #****** $(CCINT) interp.c diff --git a/psi/zfile.c b/psi/zfile.c index 2c6c958..2f27f82 100644 --- a/psi/zfile.c +++ b/psi/zfile.c @@ -197,6 +197,25 @@ check_file_permissions(i_ctx_t *i_ctx_p, const char *fname, int len, return check_file_permissions_reduced(i_ctx_p, fname_reduced, rlen, permitgroup); } +/* z_check_file_permissions: see zfile.h for explanation + */ +int +z_check_file_permissions(gs_memory_t *mem, const char *fname, const int len, const char *permission) +{ + i_ctx_t *i_ctx_p = get_minst_from_memory(mem)->i_ctx_p; + gs_parsed_file_name_t pname; + const char *permitgroup = permission[0] == 'r' ? "PermitFileReading" : "PermitFileWriting"; + int code = gs_parse_file_name(&pname, fname, len, imemory); + if (code < 0) + return code; + + if (pname.iodev && i_ctx_p->LockFilePermissions && strcmp(pname.iodev->dname, "%pipe%") == 0) + return e_invalidfileaccess; + + code = check_file_permissions(i_ctx_p, fname, len, permitgroup); + return code; +} + /* file */ int /* exported for zsysvm.c */ zfile(i_ctx_t *i_ctx_p) diff --git a/psi/zfile.h b/psi/zfile.h index fdf1373..a9399c7 100644 --- a/psi/zfile.h +++ b/psi/zfile.h @@ -22,4 +22,11 @@ int zopen_file(i_ctx_t *i_ctx_p, const gs_parsed_file_name_t *pfn, const char *file_access, stream **ps, gs_memory_t *mem); +/* z_check_file_permissions: a callback (via mem->gs_lib_ctx->client_check_file_permission) + * to allow applying the above permissions checks when opening file(s) from + * the graphics library + */ +int +z_check_file_permissions(gs_memory_t *mem, const char *fname, + const int len, const char *permission); #endif -- 2.9.1