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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Cc: Paul Eggert <eggert@cs.ucla.edu>
Subject: [PATCH 6/9] posix: fix glob bugs with long login names
Date: Tue, 05 Sep 2017 20:25:00 -0000	[thread overview]
Message-ID: <1504643122-14874-7-git-send-email-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <1504643122-14874-1-git-send-email-adhemerval.zanella@linaro.org>

Current glob implementation allows unlimited user name for home
directory construction on GLOB_TILDE case.  To accomplish it glob
either construct a name on stack if size are small enough (based
on current alloca_used) or in heap otherwise.

This patch simplifies storage allocation by using the same scratch
buffer for both get_rlogin_r and getpwnam_r.

This also syncs with gnulib commit 064df0b (glob: fix bugs with long
login names).

Checked on x86_64-linux-gnu and on a build using build-many-glibcs.py
for all major architectures.

	* posix/glob.c (GET_LOGIN_NAME_MAX): Remove.
	(glob): Use the same scratch buffer for both getlogin_r and
	getpwnam_r.  Don’t require preallocation of the login name.  This
	simplifies storage allocation, and corrects the handling of
	long login names.
---
 ChangeLog    |  7 +++++
 posix/glob.c | 88 +++++++++++++++++++++---------------------------------------
 2 files changed, 37 insertions(+), 58 deletions(-)

diff --git a/posix/glob.c b/posix/glob.c
index 340cf08..2c8a3dc 100644
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -75,12 +75,6 @@
 #include <flexmember.h>
 #include <glob_internal.h>
 #include <scratch_buffer.h>
-
-#ifdef _SC_LOGIN_NAME_MAX
-# define GET_LOGIN_NAME_MAX()	sysconf (_SC_LOGIN_NAME_MAX)
-#else
-# define GET_LOGIN_NAME_MAX()	(-1)
-#endif
 \f
 static const char *next_brace_sub (const char *begin, int flags) __THROWNL;
 
@@ -611,67 +605,45 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
 	      else
 		home_dir = "c:/users/default"; /* poor default */
 #else
-	      int success;
-	      char *name;
-	      int malloc_name = 0;
-	      size_t buflen = GET_LOGIN_NAME_MAX () + 1;
-
-	      if (buflen == 0)
-		/* 'sysconf' does not support _SC_LOGIN_NAME_MAX.  Try
-		   a moderate value.  */
-		buflen = 20;
-	      if (glob_use_alloca (alloca_used, buflen))
-		name = alloca_account (buflen, alloca_used);
-	      else
+	      int err;
+	      struct passwd *p;
+	      struct passwd pwbuf;
+	      struct scratch_buffer s;
+	      scratch_buffer_init (&s);
+	      while (true)
 		{
-		  name = malloc (buflen);
-		  if (name == NULL)
+		  p = NULL;
+		  err = __getlogin_r (s.data, s.length);
+		  if (err == 0)
 		    {
-		      retval = GLOB_NOSPACE;
-		      goto out;
-		    }
-		  malloc_name = 1;
-		}
-
-	      success = __getlogin_r (name, buflen) == 0;
-	      if (success)
-		{
-		  struct passwd *p;
-		  struct scratch_buffer pwtmpbuf;
-		  scratch_buffer_init (&pwtmpbuf);
 # if defined HAVE_GETPWNAM_R || defined _LIBC
-		  struct passwd pwbuf;
-
-		  while (getpwnam_r (name, &pwbuf,
-				     pwtmpbuf.data, pwtmpbuf.length, &p)
-			 == ERANGE)
-		    {
-		      if (!scratch_buffer_grow (&pwtmpbuf))
-			{
-			  retval = GLOB_NOSPACE;
-			  goto out;
-			}
-		    }
+		      size_t ssize = strlen (s.data) + 1;
+		      err = getpwnam_r (s.data, &pwbuf, s.data + ssize,
+					s.length - ssize, &p);
 # else
-		  p = getpwnam (name);
+		      p = getpwnam (s.data);
+		      if (p == NULL)
+			err = errno;
 # endif
-		  if (p != NULL)
+		    }
+		  if (err != ERANGE)
+		    break;
+		  if (!scratch_buffer_grow (&s))
 		    {
-		      home_dir = strdup (p->pw_dir);
-		      malloc_home_dir = 1;
-		      if (home_dir == NULL)
-			{
-			  scratch_buffer_free (&pwtmpbuf);
-			  retval = GLOB_NOSPACE;
-			  goto out;
-			}
+		      retval = GLOB_NOSPACE;
+		      goto out;
 		    }
-		  scratch_buffer_free (&pwtmpbuf);
 		}
-	      else
+	      if (err == 0)
+		{
+		  home_dir = strdup (p->pw_dir);
+		  malloc_home_dir = 1;
+		}
+	      scratch_buffer_free (&s);
+	      if (err == 0 && home_dir == NULL)
 		{
-		  if (__glibc_unlikely (malloc_name))
-		    free (name);
+		  retval = GLOB_NOSPACE;
+		  goto out;
 		}
 #endif /* WINDOWS32 */
 	    }
-- 
2.7.4

  parent reply	other threads:[~2017-09-05 20:25 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 9/9] posix: Fix glob with GLOB_NOCHECK returning modified patterns (BZ#10246) Adhemerval Zanella
2017-09-07 22:14   ` Paul Eggert
2017-09-08  9:16     ` 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 ` Adhemerval Zanella [this message]
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

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