33 lines
1.3 KiB
Diff
33 lines
1.3 KiB
Diff
From: Matthew Garrett <matthew.garrett@nebula.com>
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Date: Wed, 8 Nov 2017 15:11:34 +0000
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Subject: [15/29] ACPI: Limit access to custom_method when the kernel is locked
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down
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Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=5ff99c830aacf02f25816a0da427216fb63ba16d
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custom_method effectively allows arbitrary access to system memory, making
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it possible for an attacker to circumvent restrictions on module loading.
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Disable it if the kernel is locked down.
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Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
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Signed-off-by: David Howells <dhowells@redhat.com>
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Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
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cc: linux-acpi@vger.kernel.org
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---
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drivers/acpi/custom_method.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
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index c68e72414a67..b33fba70ec51 100644
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--- a/drivers/acpi/custom_method.c
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+++ b/drivers/acpi/custom_method.c
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@@ -29,6 +29,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf,
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struct acpi_table_header table;
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acpi_status status;
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+ if (kernel_is_locked_down("ACPI custom methods"))
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+ return -EPERM;
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+
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if (!(*ppos)) {
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/* parse the table header to get the table length */
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if (count <= sizeof(struct acpi_table_header))
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