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 <path>" 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 <[email protected]>
Analysis-by: Petr Salinger <[email protected]>
Signed-off-by: Jonathan Nieder <[email protected]>
---
Thanks, all, and sorry to take so long in sending this patch out.
Thoughts?
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
--- a/src/bltin/test.c
+++ b/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
--
To unsubscribe from this list: send the line "unsubscribe dash" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
