From d789e78a75828613951a203d132202295964014b Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Sun, 25 Dec 2005 17:33:57 +0000 Subject: [PATCH] (chdir_no_follow): Remove unnecessary test of S_ISDIR (sb_init.st_mode). --- lib/chdir-safer.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/lib/chdir-safer.c b/lib/chdir-safer.c index c61fd8b581..6106fb9815 100644 --- a/lib/chdir-safer.c +++ b/lib/chdir-safer.c @@ -44,7 +44,10 @@ /* Just like chmod, but fail if DIR is a symbolic link. This can avoid a minor race condition between when a - directory is created or stat'd and when we chdir into it. */ + directory is created or stat'd and when we chdir into it. + + Note that this function fails (while chdir would succeed) + if DIR cannot be opened with O_RDONLY. */ int chdir_no_follow (char const *dir) { @@ -56,10 +59,9 @@ chdir_no_follow (char const *dir) bool open_dereferences_symlink = ! O_NOFOLLOW; - /* If open follows symlinks, lstat DIR first to ensure that it is - a directory and to get its device and inode numbers. */ - if (open_dereferences_symlink - && (lstat (dir, &sb_init) != 0 || ! S_ISDIR (sb_init.st_mode))) + /* If open follows symlinks, lstat DIR, to get its device and + inode numbers. */ + if (open_dereferences_symlink && lstat (dir, &sb_init) != 0) return fail; fd = open (dir, O_NOFOLLOW | O_RDONLY | O_NDELAY); @@ -67,11 +69,10 @@ chdir_no_follow (char const *dir) if (0 <= fd && fstat (fd, &sb) == 0 /* If DIR is a different directory, then someone is trying to do - something nasty. However, the risk of - such an attack is so low that it isn't worth a special diagnostic. - Simply skip the fchdir and set errno (to the same value that open - uses for symlinks with O_NOFOLLOW), so that the caller can - report the failure. */ + something nasty. However, the risk of such an attack is so low + that it isn't worth a special diagnostic. Simply skip the fchdir + and set errno (to the same value that open uses for symlinks with + O_NOFOLLOW), so that the caller can report the failure. */ && ( ! open_dereferences_symlink || SAME_INODE (sb_init, sb) || ((errno = ELOOP), 0)) && fchdir (fd) == 0) -- 2.47.3