Date: Tue, 9 Dec 2003 15:54:20 +0100 From: dada@sbox.tugraz.at To: freebsd-gnats-submit@FreeBSD.org Subject: bin/60079: realpath(3) accepts zero size symbolic links Message-ID: <20031209155420.owco000444w4g0g4@webmail.tugraz.at> Resent-Message-ID: <200312091500.hB9F0ZsO054986@freefall.freebsd.org>
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>Number: 60079
>Category: bin
>Synopsis: realpath(3) accepts zero size symbolic links
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Dec 09 07:00:35 PST 2003
>Closed-Date:
>Last-Modified:
>Originator: Martin Kammerhofer
>Release: FreeBSD 4.9-STABLE i386
>Organization:
Graz University
>Environment:
System: FreeBSD Martin.liebt.Susi 4.9-STABLE FreeBSD 4.9-STABLE #0: Thu Nov 20
21:46:53 CET 2003 toor@Martin.liebt.Susi:/usr/obj/usr/src/sys/LEND4 i386
Applies to -current and -stable.
>Description:
The libc realpath(3) routine accepts zero size symbolic links
without returning any error indication. Since namei(9) will
never accept such a path this behaviour is misleading and
could confuse applications.
BTW Revision 1.13 of src/lib/libc/stdlib/realpath.3 needs a
MFC.
>How-To-Repeat:
/var/tmp$ ln -s "" ZEROLINK
/var/tmp$ realpath ZEROLINK
/var/tmp
/var/tmp$ realpath ZEROLINK/vi.recover
/var/tmp/vi.recover
>Fix:
--- src/lib/libc/stdlib/realpath.c.orig Tue Dec 9 12:48:48 2003
+++ src/lib/libc/stdlib/realpath.c Tue Dec 9 12:52:27 2003
@@ -149,11 +149,14 @@
return (NULL);
}
slen = readlink(resolved, symlink, sizeof(symlink) - 1);
- if (slen < 0)
+ if (slen <= 0) {
+ if (slen == 0)
+ errno = ENOENT;
return (NULL);
+ }
symlink[slen] = '\0';
if (symlink[0] == '/') {
- resolved[1] = 0;
+ resolved[1] = '\0';
resolved_len = 1;
} else if (resolved_len > 1) {
/* Strip the last path component. */
>Release-Note:
>Audit-Trail:
>Unformatted:
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