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From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To: robert.moore@intel.com, erik.kaneda@intel.com,
	rafael.j.wysocki@intel.com, lenb@kernel.org
Cc: linux-acpi@vger.kernel.org, devel@acpica.org,
	linux-kernel@vger.kernel.org,
	Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields
Date: Mon, 26 Apr 2021 18:41:34 -0700	[thread overview]
Message-ID: <20210427014134.3568-1-lyl2019@mail.ustc.edu.cn> (raw)

In acpi_db_walk_for_fields, buffer.pointer is freed in the first
time via ACPI_FREE() after acpi_os_printf("%s ", (char *)buffer.pointer).
But later, buffer.pointer is assigned to ret_value, and the freed
pointer is dereferenced by ret_value, which is use after free.

In addition, buffer.pointer is freed by ACPI_FREE() again after
acpi_os_printf("}\n"), which is a double free.

My patch removes the first ACPI_FREE() to avoid the uaf and double
free bugs.

Fixes: 5fd033288a866 ("ACPICA: debugger: add command to dump all fields of particular subtype")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/acpi/acpica/dbnames.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/acpi/acpica/dbnames.c b/drivers/acpi/acpica/dbnames.c
index 3615e1a6efd8..dabd76df15ec 100644
--- a/drivers/acpi/acpica/dbnames.c
+++ b/drivers/acpi/acpica/dbnames.c
@@ -547,7 +547,6 @@ acpi_db_walk_for_fields(acpi_handle obj_handle,
 	}
 
 	acpi_os_printf("%s ", (char *)buffer.pointer);
-	ACPI_FREE(buffer.pointer);
 
 	buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
 	acpi_evaluate_object(obj_handle, NULL, NULL, &buffer);
-- 
2.25.1



             reply	other threads:[~2021-04-27  1:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-27  1:41 Lv Yunlong [this message]
2021-04-29 18:00 ` [PATCH] ACPICA:dbnames: Fix a error free in acpi_db_walk_for_fields Kaneda, Erik
2021-05-05 23:11   ` Kaneda, Erik

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