[gentoo-portage-dev] [PATCH] varexpand: fix IndexError (bug 548556)

[gentoo-portage-dev] [PATCH] varexpand: fix IndexError (bug 548556)

[Zac Medico]

This handles two cases where varexpand incremented the index without
checking bounds.

X-Gentoo-Bug: 548556
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=548556
X-Gentoo-forum-thread: https://forums.gentoo.org/viewtopic-t-1016432.html
---
 pym/portage/util/__init__.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/pym/portage/util/__init__.py b/pym/portage/util/__init__.py
index 48cd1b7..c0b509b 100644
--- a/pym/portage/util/__init__.py
+++ b/pym/portage/util/__init__.py
@@ -850,8 +850,20 @@ def varexpand(mystring, mydict=None, error_leader=None):
 					continue
 			elif current == "$":
 				pos += 1
+				if pos == length:
+					# shells handle this like \$
+					newstring.append(current)
+					continue
+
 				if mystring[pos] == "{":
 					pos += 1
+					if pos == length:
+						msg = _varexpand_unexpected_eof_msg
+						if error_leader is not None:
+							msg = error_leader() + msg
+						writemsg(msg + "\n", noiselevel=-1)
+						return ""
+
 					braced = True
 				else:
 					braced = False
-- 
2.3.5

Re: [gentoo-portage-dev] [PATCH] varexpand: fix IndexError (bug 548556)

[Brian Dolbec]

On Sun,  3 May 2015 23:01:58 -0700
Zac Medico <zmedico@gentoo.org> wrote:

> This handles two cases where varexpand incremented the index without
> checking bounds.
> 
> X-Gentoo-Bug: 548556
> X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=548556
> X-Gentoo-forum-thread:
> https://forums.gentoo.org/viewtopic-t-1016432.html ---
>  pym/portage/util/__init__.py | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/pym/portage/util/__init__.py
> b/pym/portage/util/__init__.py index 48cd1b7..c0b509b 100644
> --- a/pym/portage/util/__init__.py
> +++ b/pym/portage/util/__init__.py
> @@ -850,8 +850,20 @@ def varexpand(mystring, mydict=None,
> error_leader=None): continue
>  			elif current == "$":
>  				pos += 1
> +				if pos == length:
> +					# shells handle this like \$
> +					newstring.append(current)
> +					continue
> +
>  				if mystring[pos] == "{":
>  					pos += 1
> +					if pos == length:
> +						msg =
> _varexpand_unexpected_eof_msg
> +						if error_leader is
> not None:
> +							msg =
> error_leader() + msg
> +						writemsg(msg + "\n",
> noiselevel=-1)
> +						return ""
> +
>  					braced = True
>  				else:
>  					braced = False


Yeah, good idea, looks good.

-- 
Brian Dolbec <dolsen>