44 lines
1.2 KiB
Diff
44 lines
1.2 KiB
Diff
From 673ff3585880ccacc53abaea01df027859ed5c1b Mon Sep 17 00:00:00 2001
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From: root <root@localhost.localdomain>
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Date: Wed, 13 Mar 2019 14:44:36 +0800
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Subject: [PATCH 14/17] libdm: add memory barrier
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Just for case ensure compiler is not able to optimize
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memset() away for resources that are released.
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This idea of using memory barrier is taken from openssl.
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Other options would be to check for 'explicit_bzero' function.
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(cherry picked from commit 55a8d6c86b4c6c6c707cfcc3dd887bca0632114f)
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Conflicts:
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device_mapper/ioctl/libdm-iface.c
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---
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libdm/ioctl/libdm-iface.c | 2 ++
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1 file changed, 2 insertions(+)
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diff --git a/libdm/ioctl/libdm-iface.c b/libdm/ioctl/libdm-iface.c
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index 769b69c..7f48e37 100644
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--- a/libdm/ioctl/libdm-iface.c
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+++ b/libdm/ioctl/libdm-iface.c
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@@ -466,6 +466,7 @@ static void _dm_zfree_string(char *string)
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{
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if (string) {
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memset(string, 0, strlen(string));
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+ asm volatile ("" ::: "memory"); /* Compiler barrier. */
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dm_free(string);
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}
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}
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@@ -474,6 +475,7 @@ static void _dm_zfree_dmi(struct dm_ioctl *dmi)
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{
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if (dmi) {
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memset(dmi, 0, dmi->data_size);
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+ asm volatile ("" ::: "memory"); /* Compiler barrier. */
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dm_free(dmi);
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}
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}
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--
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2.19.1
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