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From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@kernel.org
Cc: stable-review@kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk,
	"Krzysztof Hałasa" <khc@pm.waw.pl>,
	"Michal Marek" <mmarek@suse.cz>
Subject: [159/165] kbuild: Fix modpost segfault
Date: Fri, 30 Jul 2010 10:16:27 -0700	[thread overview]
Message-ID: <20100730171514.013999005@clark.site> (raw)
In-Reply-To: <20100730171550.GA1299@kroah.com

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2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Krzysztof Halasa <khc@pm.waw.pl>

commit 1c938663d58b5b2965976a6f54cc51b5d6f691aa upstream.

Alan <alan@clueserver.org> writes:

> program: /home/alan/GitTrees/linux-2.6-mid-ref/scripts/mod/modpost -o
> Module.symvers -S vmlinux.o
>
> Program received signal SIGSEGV, Segmentation fault.

It just hit me.
It's the offset calculation in reloc_location() which overflows:
        return (void *)elf->hdr + sechdrs[section].sh_offset +
               (r->r_offset - sechdrs[section].sh_addr);

E.g. for the first rodata r entry:
r->r_offset < sechdrs[section].sh_addr
and the expression in the parenthesis produces 0xFFFFFFE0 or something
equally wise.

Reported-by: Alan <alan@clueserver.org>
Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Tested-by: Alan <alan@clueserver.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 scripts/mod/modpost.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1311,7 +1311,7 @@ static unsigned int *reloc_location(stru
 	int section = sechdr->sh_info;
 
 	return (void *)elf->hdr + sechdrs[section].sh_offset +
-		(r->r_offset - sechdrs[section].sh_addr);
+		r->r_offset - sechdrs[section].sh_addr;
 }
 
 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)



                 reply	other threads:[~2010-07-30 17:23 UTC|newest]

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