lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 01 Mar 2024 18:12:41 -0000
From: "tip-bot2 for Jiri Bohac" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Jiri Bohac <jbohac@...e.cz>, "Borislav Petkov (AMD)" <bp@...en8.de>,
  <stable@...nel.org>, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/e820: Don't reserve SETUP_RNG_SEED in e820

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     1a2cbc38b74f10c11837f88475d683c69c8503f6
Gitweb:        https://git.kernel.org/tip/1a2cbc38b74f10c11837f88475d683c69c8503f6
Author:        Jiri Bohac <jbohac@...e.cz>
AuthorDate:    Wed, 31 Jan 2024 01:04:28 +01:00
Committer:     Dave Hansen <dave.hansen@...ux.intel.com>
CommitterDate: Fri, 01 Mar 2024 08:34:25 -08:00

x86/e820: Don't reserve SETUP_RNG_SEED in e820

SETUP_RNG_SEED in setup_data is supplied by kexec and should
not be reserved in the e820 map.

Doing so reserves 16 bytes of RAM when booting with kexec.
(16 bytes because data->len is zeroed by parse_setup_data so only
sizeof(setup_data) is reserved.)

When kexec is used repeatedly, each boot adds two entries in the
kexec-provided e820 map as the 16-byte range splits a larger
range of usable memory. Eventually all of the 128 available entries
get used up. The next split will result in losing usable memory
as the new entries cannot be added to the e820 map.

Fixes: 68b8e9713c8e ("x86/setup: Use rng seeds from setup_data")
Signed-off-by: Jiri Bohac <jbohac@...e.cz>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Cc: <stable@...nel.org>
Link: https://lore.kernel.org/r/ZbmOjKnARGiaYBd5@dwarf.suse.cz
---
 arch/x86/kernel/e820.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index fb8cf95..b66f540 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1017,10 +1017,12 @@ void __init e820__reserve_setup_data(void)
 		e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
 
 		/*
-		 * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
-		 * to be reserved.
+		 * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
+		 * kexec and do not need to be reserved.
 		 */
-		if (data->type != SETUP_EFI && data->type != SETUP_IMA)
+		if (data->type != SETUP_EFI &&
+		    data->type != SETUP_IMA &&
+		    data->type != SETUP_RNG_SEED)
 			e820__range_update_kexec(pa_data,
 						 sizeof(*data) + data->len,
 						 E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ