From f4f50ceea8e8852b8c3ac73f5807d8b54b735c3e Mon Sep 17 00:00:00 2001 From: Chris Liddell Date: Tue, 21 Aug 2018 20:17:05 +0100 Subject: [PATCH 5/5] Bug 699657: properly apply file permissions to .tempfile CVE: CVE-2018-15908 Upstream-Status: Backport [git://git.ghostscript.com/ghostpdl.git] Signed-off-by: Hongxu Jia --- psi/zfile.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/psi/zfile.c b/psi/zfile.c index a0acd5a..19996b0 100644 --- a/psi/zfile.c +++ b/psi/zfile.c @@ -134,7 +134,7 @@ check_file_permissions_reduced(i_ctx_t *i_ctx_p, const char *fname, int len, /* we're protecting arbitrary file system accesses, not Postscript device accesses. * Although, note that %pipe% is explicitly checked for and disallowed elsewhere */ - if (iodev != iodev_default(imemory)) { + if (iodev && iodev != iodev_default(imemory)) { return 0; } @@ -734,7 +734,23 @@ ztempfile(i_ctx_t *i_ctx_p) } if (gp_file_name_is_absolute(pstr, strlen(pstr))) { - if (check_file_permissions(i_ctx_p, pstr, strlen(pstr), + int plen = strlen(pstr); + const char *sep = gp_file_name_separator(); +#ifdef DEBUG + int seplen = strlen(sep); + if (seplen != 1) + return_error(gs_error_Fatal); +#endif + /* strip off the file name prefix, leave just the directory name + * so we can check if we are allowed to write to it + */ + for ( ; plen >=0; plen--) { + if (pstr[plen] == sep[0]) + break; + } + memcpy(fname, pstr, plen); + fname[plen] = '\0'; + if (check_file_permissions(i_ctx_p, fname, strlen(fname), NULL, "PermitFileWriting") < 0) { code = gs_note_error(gs_error_invalidfileaccess); goto done; -- 2.8.1