From: George Dunlap <george.dunlap@eu.citrix.com>
To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
mattjd@gmail.com, security@xen.org
Subject: Re: [PATCH 18/23] libxc: Add range checking to xc_dom_binloader
Date: Fri, 14 Jun 2013 16:19:04 +0100 [thread overview]
Message-ID: <51BB3468.6060004@eu.citrix.com> (raw)
In-Reply-To: <20923.13137.527678.760500@mariner.uk.xensource.com>
On 14/06/13 16:14, Ian Jackson wrote:
> George Dunlap writes ("Re: [Xen-devel] [PATCH 18/23] libxc: Add range checking to xc_dom_binloader"):
>> if ( dom->kernel-size - sizeof(*table) > 8192)
>> ptr_end = dom->kernel_blob + 8192
>> else
>> ptr_end = dom->kernel_size - sizeof(*table);
>>
>> Or something along those lines?
> Yes, I said something similar to Chuck. Except that your code has a
> bug if kernel_size < sizeof(*table) :-).
...no, because that's already checked by the previous hunk of your
patch. :-)
> TBH I think I'd rather not disturb this any more than necessary.
I think disturbing it in a way that is obviously correct is better than
disturbing it in a way that looks redundant.
But I do think that the code in the patch you have, while unnecessarily
confusing and likely to trip someone up down the road, will do what the
patch claims it will do.
-George
next prev parent reply other threads:[~2013-06-14 15:19 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 18:14 [PATCH v8 00/23] XSA55 libelf fixes for unstable Ian Jackson
2013-06-13 18:14 ` [PATCH 01/23] libelf: abolish libelf-relocate.c Ian Jackson
2013-06-13 18:14 ` [PATCH 02/23] libxc: introduce xc_dom_seg_to_ptr_pages Ian Jackson
2013-06-13 18:14 ` [PATCH 03/23] libxc: Fix range checking in xc_dom_pfn_to_ptr etc Ian Jackson
2013-06-13 18:14 ` [PATCH 04/23] libelf: add `struct elf_binary*' parameter to elf_load_image Ian Jackson
2013-06-13 18:14 ` [PATCH 05/23] libelf: abolish elf_sval and elf_access_signed Ian Jackson
2013-06-13 18:14 ` [PATCH 06/23] libelf: move include of <asm/guest_access.h> to top of file Ian Jackson
2013-06-13 18:14 ` [PATCH 07/23] libelf/xc_dom_load_elf_symtab: Do not use "syms" uninitialised Ian Jackson
2013-06-13 18:14 ` [PATCH 08/23] libelf: introduce macros for memory access and pointer handling Ian Jackson
2013-06-13 18:14 ` [PATCH 09/23] tools/xcutils/readnotes: adjust print_l1_mfn_valid_note Ian Jackson
2013-06-13 18:14 ` [PATCH 10/23] libelf: check nul-terminated strings properly Ian Jackson
2013-06-13 18:14 ` [PATCH 11/23] libelf: check all pointer accesses Ian Jackson
2013-06-13 18:14 ` [PATCH 12/23] libelf: Check pointer references in elf_is_elfbinary Ian Jackson
2013-06-13 18:14 ` [PATCH 13/23] libelf: Make all callers call elf_check_broken Ian Jackson
2013-06-13 18:14 ` [PATCH 14/23] libelf: use C99 bool for booleans Ian Jackson
2013-06-13 18:14 ` [PATCH 15/23] libelf: use only unsigned integers Ian Jackson
2013-06-13 18:14 ` [PATCH 16/23] libelf: check loops for running away Ian Jackson
2013-06-13 18:14 ` [PATCH 17/23] libelf: abolish obsolete macros Ian Jackson
2013-06-13 18:14 ` [PATCH 18/23] libxc: Add range checking to xc_dom_binloader Ian Jackson
2013-06-14 14:53 ` George Dunlap
2013-06-14 15:03 ` Ian Jackson
2013-06-14 15:09 ` George Dunlap
2013-06-14 15:12 ` George Dunlap
2013-06-14 15:13 ` George Dunlap
2013-06-14 15:14 ` Ian Jackson
2013-06-14 15:19 ` George Dunlap [this message]
2013-06-14 15:24 ` Ian Jackson
2013-06-14 15:29 ` George Dunlap
2013-06-13 18:14 ` [PATCH 19/23] libxc: check failure of xc_dom_*_to_ptr, xc_map_foreign_range Ian Jackson
2013-06-13 18:14 ` [PATCH 20/23] libxc: check return values from malloc Ian Jackson
2013-06-13 18:15 ` [PATCH 21/23] libxc: range checks in xc_dom_p2m_host and _guest Ian Jackson
2013-06-13 18:15 ` [PATCH 22/23] libxc: check blob size before proceeding in xc_dom_check_gzip Ian Jackson
2013-06-13 18:15 ` [PATCH 23/23] libxc: Better range check in xc_dom_alloc_segment Ian Jackson
2013-06-13 18:18 ` [PATCH v8 00/23] XSA55 libelf fixes for unstable Ian Jackson
-- strict thread matches above, loose matches on Subject: below --
2013-06-13 18:18 [PATCH v8 00/22] XSA55 libelf fixes for Xen 4.2 Ian Jackson
2013-06-13 18:18 ` [PATCH 18/23] libxc: Add range checking to xc_dom_binloader Ian Jackson
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