linux-kernel - [PATCH for stable] kbuild: Fix modpost segfault

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100629094341.GA26045@sepie.suse.cz>
Date:	Tue, 29 Jun 2010 11:43:42 +0200
From:	Michal Marek <mmarek@...e.cz>
To:	stable@...nel.org
Cc:	Krzysztof Hałasa <khc@...waw.pl>,
	Alan <alan@...eserver.org>, linux-kernel@...r.kernel.org
Subject: [PATCH for stable] kbuild: Fix modpost segfault

Hi Greg,

please add this to stable, it's a bug that started showing up with newer
gcc. The upstream commit is 1c938663d58b5b2965976a6f54cc51b5d6f691aa.

Thanks,
Michal

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

Alan <alan@...eserver.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@...eserver.org>
Signed-off-by: Krzysztof Hałasa <khc@...waw.pl>
Tested-by: Alan <alan@...eserver.org>
Signed-off-by: Michal Marek <mmarek@...e.cz>


diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 3318692..f877900 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1342,7 +1342,7 @@ static unsigned int *reloc_location(struct elf_info *elf,
 	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)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/