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From: Paul Eggert <eggert@cs.ucla.edu>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	libc-alpha@sourceware.org
Subject: Re: [PATCH 9/9] posix: Fix glob with GLOB_NOCHECK returning modified patterns (BZ#10246)
Date: Thu, 07 Sep 2017 22:14:00 -0000	[thread overview]
Message-ID: <2a8058e8-4859-d75b-a16d-7ea0dd61ffd7@cs.ucla.edu> (raw)
In-Reply-To: <1504643122-14874-10-git-send-email-adhemerval.zanella@linaro.org>

Although this is a definite bug and the patch fixes this instance of it, I'm 
afraid other instances remain unfixed. For example:

    glob_t g; glob ("//a*b", 0, NULL, &g)

can do the wrong thing, since glob calls opendir on "/" instead of "//", and on 
some platforms "/" and "//" are different directories (POSIX allows this as a 
special exception).

A more serious example. If you do this:

   ln -s /no-such-file globlink1
   ln -s . globlink2

then:

       glob_t g;
       int res = glob ("globlink[12]/", 0, NULL, &g);
       assert (res == 0 && g.gl_pathc == 1);
       assert (strcmp (g.gl_pathv[0], "globlink2/") == 0);

fails, since glob gets confused about directories and slashes and mistakenly 
returns two results. Although this bug is seemingly unrelated, the underlying 
cause is the same: glob gets confused about whether to include or exclude 
slashes when doing its tests.

I'll take a look at it, though the fix won't be trivial.

PS. This finishes my review of this patchset. Patches 1-8 are OK to be 
installed, with the trivial changes I suggested earlier. This patch (patch 9) 
I'd like to hold off on, until we've had a chance to work out a 
more-comprehensive fix.

PPS. I'm still slowly wending my way through your original patchset. Most 
recently I looked at "[PATCH 07/18] posix: User LOGIN_NAME_MAX for all user 
names in glob" <https://sourceware.org/ml/libc-alpha/2017-08/msg00447.html>. I'm 
afraid a good fix needs to be hairier there too, as POSIX does not require 
LOGIN_NAME_MAX to be suitable for a stack-based buffer, or even to be defined. I 
have a partly-drafted patch which I hope to finish in the not-too-distant future.

  reply	other threads:[~2017-09-07 22:14 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-05 20:25 [PATCH 0/9] posix: glob fixes and refactor Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 8/9] posix: Use enum for __glob_pattern_type result Adhemerval Zanella
2017-09-06  1:30   ` Paul Eggert
2017-09-06  4:18   ` Paul Eggert
2017-09-06 13:04     ` Adhemerval Zanella
2017-09-06 16:18       ` Paul Eggert
2017-09-06 16:54         ` Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 5/9] posix: Fix getpwnam_r usage (BZ #1062) Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 6/9] posix: fix glob bugs with long login names Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 3/9] posix: Allow glob to match dangling symlinks [BZ #866] Adhemerval Zanella
2017-09-06  1:27   ` Paul Eggert
2017-09-06 12:57     ` Adhemerval Zanella
2017-09-09  9:50   ` Andreas Schwab
2017-09-09 11:56     ` Adhemerval Zanella
2017-09-09 17:02       ` Paul Eggert
2017-09-09 17:11         ` Zack Weinberg
2017-09-09 17:26           ` Andreas Schwab
2017-09-09 17:33             ` Zack Weinberg
2017-09-10  8:19         ` Adhemerval Zanella
2017-09-10 17:13           ` Paul Eggert
2017-09-11 14:34           ` Joseph Myers
2017-09-11 14:38             ` Zack Weinberg
2017-09-11 16:53               ` Paul Eggert
2017-09-11 17:25                 ` Zack Weinberg
2017-09-11 17:38                   ` Paul Eggert
2017-09-11 17:56                     ` Zack Weinberg
2017-09-11 18:03                       ` Paul Eggert
2017-09-11 20:09                         ` Adhemerval Zanella
2017-09-13  9:14                           ` Paul Eggert
2017-09-13 12:22                             ` Adhemerval Zanella
2017-09-14 10:05                               ` Szabolcs Nagy
2017-09-14 13:43                                 ` Adhemerval Zanella
2017-09-15 20:18                             ` Florian Weimer
2017-09-15 20:27                               ` Adhemerval Zanella
2017-09-17  7:16                               ` Paul Eggert
2017-09-17  7:48                                 ` Florian Weimer
2017-09-17 14:18                                   ` Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 1/9] posix: Sync glob with gnulib [BZ #1062] Adhemerval Zanella
2017-09-06  2:01   ` Paul Eggert
2017-09-06 12:52     ` Adhemerval Zanella
2017-09-12 14:20   ` Andreas Schwab
2017-09-12 17:06     ` Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 4/9] Sync scratch_buffer with gnulib Adhemerval Zanella
2017-09-18  6:09   ` Florian Weimer
2017-09-18 11:43     ` Adhemerval Zanella
2017-09-18 11:57       ` Florian Weimer
2017-09-18 12:25         ` Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 2/9] posix: accept inode 0 is a valid inode number (BZ #19971) Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 7/9] posix: Consolidate glob implementation Adhemerval Zanella
2017-09-12  7:35   ` Andreas Schwab
2017-09-12 14:08     ` Adhemerval Zanella
2017-09-12 14:17       ` Andreas Schwab
2017-09-12 14:29     ` Joseph Myers
2017-09-12 14:39       ` Andreas Schwab
2017-09-12 14:50         ` Joseph Myers
2017-09-12 12:56   ` Andreas Schwab
2017-09-12 14:22     ` Adhemerval Zanella
2017-09-12 14:34       ` Andreas Schwab
2017-09-13 12:26         ` Adhemerval Zanella
2017-09-05 20:25 ` [PATCH 9/9] posix: Fix glob with GLOB_NOCHECK returning modified patterns (BZ#10246) Adhemerval Zanella
2017-09-07 22:14   ` Paul Eggert [this message]
2017-09-08  9:16     ` Adhemerval Zanella

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