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Re: bug#10472: [PATCH] canonicalize: fix // handling
From: |
Eric Blake |
Subject: |
Re: bug#10472: [PATCH] canonicalize: fix // handling |
Date: |
Sat, 04 Feb 2012 10:59:21 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20120131 Thunderbird/10.0 |
On 02/04/2012 09:56 AM, Eric Blake wrote:
> On Cygwin, and other platforms where // is detected as distinct
> from / at configure time, the canonicalize routines were incorrectly
> treating all instances of multiple leading slashes as //.
> See also coreutils bug http://debbugs.gnu.org/10472
>
> * lib/canonicalize.c (canonicalize_filename_mode): Don't convert
> /// to //, since only // is special.
>
> +++ b/lib/canonicalize.c
> @@ -145,7 +145,7 @@ canonicalize_filename_mode (const char *name,
> canonicalize_mode_t can_mode)
> rname_limit = rname + PATH_MAX;
> rname[0] = '/';
> dest = rname + 1;
> - if (DOUBLE_SLASH_IS_DISTINCT_ROOT && name[1] == '/')
> + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && name[1] == '/' && name[2] != '/')
> *dest++ = '/';
This never initializes rname[1] if name is "///",
> @@ -295,7 +296,8 @@ canonicalize_filename_mode (const char *name,
> canonicalize_mode_t can_mode)
> }
> if (dest > rname + 1 && dest[-1] == '/')
> --dest;
> - if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1 && *dest == '/')
> + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1
> + && *dest == '/' && dest[1] != '/')
> dest++;
which meant this was reading uninitialized memory, and depending on what
was in the heap, might canonicalize "///" to "/" or "//". I'm pushing
this additional fix to both files:
diff --git i/lib/canonicalize-lgpl.c w/lib/canonicalize-lgpl.c
index a61bef9..08e76fe 100644
--- i/lib/canonicalize-lgpl.c
+++ w/lib/canonicalize-lgpl.c
@@ -158,6 +158,7 @@ __realpath (const char *name, char *resolved)
dest = rpath + 1;
if (DOUBLE_SLASH_IS_DISTINCT_ROOT && name[1] == '/' && name[2] !=
'/')
*dest++ = '/';
+ *dest = '\0';
}
for (start = end = name; *start; start = end)
diff --git i/lib/canonicalize.c w/lib/canonicalize.c
index ed094b7..2c73094 100644
--- i/lib/canonicalize.c
+++ w/lib/canonicalize.c
@@ -147,6 +147,7 @@ canonicalize_filename_mode (const char *name,
canonicalize_mode_t can_mode)
dest = rname + 1;
if (DOUBLE_SLASH_IS_DISTINCT_ROOT && name[1] == '/' && name[2] !=
'/')
*dest++ = '/';
+ *dest = '\0';
}
for (start = name; *start; start = end)
--
Eric Blake address@hidden +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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