2010-11-22 19:34:48

by Mariusz Kozlowski

Subject: [PATCH] ide: fix use after free in ide-acpi

out_obj points to kfreed memory and we dereference that pointer in
DEBPRINT/printk.

Signed-off-by: Mariusz Kozlowski <[email protected]>
---
drivers/ide/ide-acpi.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ide/ide-acpi.c b/drivers/ide/ide-acpi.c
index c26c119..2af8cb4 100644
--- a/drivers/ide/ide-acpi.c
+++ b/drivers/ide/ide-acpi.c
@@ -416,21 +416,21 @@ void ide_acpi_get_timing(ide_hwif_t *hwif)

out_obj = output.pointer;
if (out_obj->type != ACPI_TYPE_BUFFER) {
- kfree(output.pointer);
DEBPRINT("Run _GTM: error: "
"expected object type of ACPI_TYPE_BUFFER, "
"got 0x%x\n", out_obj->type);
+ kfree(output.pointer);
return;
}

if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
out_obj->buffer.length != sizeof(struct GTM_buffer)) {
- kfree(output.pointer);
printk(KERN_ERR
"%s: unexpected _GTM length (0x%x)[should be 0x%zx] or "
"addr (0x%p)\n",
__func__, out_obj->buffer.length,
sizeof(struct GTM_buffer), out_obj->buffer.pointer);
+ kfree(output.pointer);
return;
}

--
1.7.0.4

2010-11-22 19:37:06

by David Miller

Subject: Re: [PATCH] ide: fix use after free in ide-acpi

From: Mariusz Kozlowski <[email protected]>
Date: Mon, 22 Nov 2010 20:34:38 +0100

> out_obj points to kfreed memory and we dereference that pointer in
> DEBPRINT/printk.
>
> Signed-off-by: Mariusz Kozlowski <[email protected]>

Applied, thanks.