* [PATCH] Guard check in module loader against integer overflow
@ 2012-05-22 14:56 David Howells
2012-05-23 12:11 ` Rusty Russell
0 siblings, 1 reply; 2+ messages in thread
From: David Howells @ 2012-05-22 14:56 UTC (permalink / raw)
To: rusty; +Cc: linux-kernel, David Howells
The check:
if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr))
may not work if there's an overflow in the right-hand side of the condition.
Signed-off-by: David Howells <dhowells@redhat.com>
---
kernel/module.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 78ac6ec..377cb06 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2429,7 +2429,8 @@ static int copy_and_check(struct load_info *info,
goto free_hdr;
}
- if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr)) {
+ if (hdr->e_shoff >= len ||
+ hdr->e_shnum * sizeof(Elf_Shdr) > len - hdr->e_shoff) {
err = -ENOEXEC;
goto free_hdr;
}
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] Guard check in module loader against integer overflow
2012-05-22 14:56 [PATCH] Guard check in module loader against integer overflow David Howells
@ 2012-05-23 12:11 ` Rusty Russell
0 siblings, 0 replies; 2+ messages in thread
From: Rusty Russell @ 2012-05-23 12:11 UTC (permalink / raw)
To: David Howells; +Cc: linux-kernel, David Howells
On Tue, 22 May 2012 15:56:13 +0100, David Howells <dhowells@redhat.com> wrote:
> The check:
>
> if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr))
>
> may not work if there's an overflow in the right-hand side of the condition.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
Thanks; though the sanity checks are merely against accidents, not
malice, it's worth fixing.
Applied,
Rusty.
^ permalink raw reply [flat|nested] 2+ messages in thread
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