From 7df60e06e6a176e2ee177df015d5e7ecc80ed229 Mon Sep 17 00:00:00 2001 From: Jonathan Nieder Date: Mon, 26 Sep 2011 16:16:37 -0500 Subject: [BUILTIN] Fix "test -x" as root on platforms with old-fashioned faccessat() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When dash switched from its own emulation to the true faccessat in v0.5.7~54 (2010-04-02), on some platforms (e.g., old versions of glibc-bsd), "test -x " started returning true on all files when run as root. This violates POSIX.1-2008 ยง4.4 "File Access Permission", which says: If execute permission is requested, access shall be granted if execute permission is granted to at least one user by the file permission bits or by an alternate access control mechanism; otherwise, access shall be denied. Unfortunately, for historical reasons, access() and faccessat() are allowed by POSIX to return success for X_OK when the current process is privileged even when the above condition is not fulfilled and actual execution would fail. Work around this by checking the permissions bits when mode == X_OK and geteuid() == 0. Reported-by: Christoph Egger Analysis-by: Petr Salinger Signed-off-by: Jonathan Nieder --- src/bltin/test.c | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/src/bltin/test.c b/src/bltin/test.c index 90135e14..1093b59f 100644 --- src/bltin/test.c +++ src/bltin/test.c @@ -485,8 +485,19 @@ equalf (const char *f1, const char *f2) } #ifdef HAVE_FACCESSAT +static int has_exec_bit_set(const char *path) +{ + struct stat64 st; + + if (stat64(path, &st)) + return 0; + return st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH); +} + static int test_file_access(const char *path, int mode) { + if (mode == X_OK && geteuid() == 0 && !has_exec_bit_set(path)) + return 0; return !faccessat(AT_FDCWD, path, mode, AT_EACCESS); } #else /* HAVE_FACCESSAT */ -- 1.7.7.rc1