From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 29553 invoked from network); 12 May 2022 13:00:24 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 12 May 2022 13:00:24 -0000 Received: (qmail 24213 invoked by uid 550); 12 May 2022 13:00:21 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 24166 invoked from network); 12 May 2022 13:00:20 -0000 Date: Thu, 12 May 2022 09:00:08 -0400 From: Rich Felker To: Ismael Luceno Cc: musl@lists.openwall.com Message-ID: <20220512130008.GI7074@brightrain.aerifal.cx> References: <20220123155955.16484-1-ismael@iodev.co.uk> <20220123155955.16484-2-ismael@iodev.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220123155955.16484-2-ismael@iodev.co.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] [PATCH v3 1/2] nftw: implement FTW_CHDIR On Sun, Jan 23, 2022 at 04:59:54PM +0100, Ismael Luceno wrote: > Signed-off-by: Ismael Luceno > --- > src/misc/nftw.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/src/misc/nftw.c b/src/misc/nftw.c > index 5b233b2b8e77..7569a657e54e 100644 > --- a/src/misc/nftw.c > +++ b/src/misc/nftw.c > @@ -87,6 +87,14 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int, > DIR *d = fdopendir(dfd); > if (d) { > struct dirent *de; > + if (flags & FTW_CHDIR) { > + if (!fchdir(dfd)) { > + err = errno; > + closedir(d); > + errno = err; > + return -1; > + } > + } > while ((de = readdir(d))) { > if (de->d_name[0] == '.' > && (!de->d_name[1] I'm not sure how this works -- after the fchdir, subsequent open at line 69 will fail because the pathname is no longer valid relative to the new working directory. I think different logic is needed at that point too in order to adjust the argument to open depending on FTW_CHDIR (or the whole thing could be converted to using at functions, but that's a much bigger change I'd really only want to do in a full overhaul of this function). I'm guessing you only tested with absolute pathnames. > @@ -123,6 +131,7 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str > int r, cs; > size_t l; > char pathbuf[PATH_MAX+1]; > + int orig_dfd; > > if (fd_limit <= 0) return 0; > > @@ -133,9 +142,22 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str > } > memcpy(pathbuf, path, l+1); > > + if (flags & FTW_CHDIR) { > + orig_dfd = open(".", O_CLOEXEC | O_PATH); > + if (orig_dfd < 0) > + return -1; > + } > + > pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); > r = do_nftw(pathbuf, fn, fd_limit, flags, NULL); > pthread_setcancelstate(cs, 0); > + if (flags & FTW_CHDIR) { > + if (!fchdir(orig_dfd)) > + r = -1; > + int err = errno; > + close(orig_dfd); > + errno = err; > + } > return r; > } > > -- > 2.33.0 The added open and close calls need to be inside the range where cancellation is blocked. Otherwise they will cause nftw to act on cancellation. Rich