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* [PATCH AUTOSEL 4.9 01/27] ARC: u-boot args: check that magic number is correct
@ 2019-03-30  0:55 Sasha Levin
  2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 02/27] perf/core: Restore mmap record type correctly Sasha Levin
                   ` (25 more replies)
  0 siblings, 26 replies; 27+ messages in thread
From: Sasha Levin @ 2019-03-30  0:55 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Eugeniy Paltsev, Vineet Gupta, Sasha Levin, linux-snps-arc

From: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>

[ Upstream commit edb64bca50cd736c6894cc6081d5263c007ce005 ]

In case of devboards we really often disable bootloader and load
Linux image in memory via JTAG. Even if kernel tries to verify
uboot_tag and uboot_arg there is sill a chance that we treat some
garbage in registers as valid u-boot arguments in JTAG case.
E.g. it is enough to have '1' in r0 to treat any value in r2 as
a boot command line.

So check that magic number passed from u-boot is correct and drop
u-boot arguments otherwise. That helps to reduce the possibility
of using garbage as u-boot arguments in JTAG case.

We can safely check U-boot magic value (0x0) in linux passed via
r1 register as U-boot pass it from the beginning. So there is no
backward-compatibility issues.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arc/kernel/head.S  | 1 +
 arch/arc/kernel/setup.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 1f945d0f40da..208bf2c9e7b0 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -107,6 +107,7 @@ ENTRY(stext)
 	;    r2 = pointer to uboot provided cmdline or external DTB in mem
 	; These are handled later in handle_uboot_args()
 	st	r0, [@uboot_tag]
+	st      r1, [@uboot_magic]
 	st	r2, [@uboot_arg]
 #endif
 
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 9119bea503a7..9f96120eee6e 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -32,6 +32,7 @@ unsigned int intr_to_DE_cnt;
 
 /* Part of U-boot ABI: see head.S */
 int __initdata uboot_tag;
+int __initdata uboot_magic;
 char __initdata *uboot_arg;
 
 const struct machine_desc *machine_desc;
@@ -400,6 +401,8 @@ static inline bool uboot_arg_invalid(unsigned long addr)
 #define UBOOT_TAG_NONE		0
 #define UBOOT_TAG_CMDLINE	1
 #define UBOOT_TAG_DTB		2
+/* We always pass 0 as magic from U-boot */
+#define UBOOT_MAGIC_VALUE	0
 
 void __init handle_uboot_args(void)
 {
@@ -415,6 +418,11 @@ void __init handle_uboot_args(void)
 		goto ignore_uboot_args;
 	}
 
+	if (uboot_magic != UBOOT_MAGIC_VALUE) {
+		pr_warn(IGNORE_ARGS "non zero uboot magic\n");
+		goto ignore_uboot_args;
+	}
+
 	if (uboot_tag != UBOOT_TAG_NONE &&
             uboot_arg_invalid((unsigned long)uboot_arg)) {
 		pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
-- 
2.19.1


^ permalink raw reply related	[flat|nested] 27+ messages in thread
end of thread, other threads:[~2019-03-30  1:02 UTC | newest]

Thread overview: 27+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2019-03-30  0:55 [PATCH AUTOSEL 4.9 01/27] ARC: u-boot args: check that magic number is correct Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 02/27] perf/core: Restore mmap record type correctly Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 03/27] ext4: add missing brelse() in add_new_gdb_meta_bg() Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 04/27] ext4: report real fs size after failed resize Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 05/27] ALSA: echoaudio: add a check for ioremap_nocache Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 06/27] ALSA: sb8: add a check for request_region Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 07/27] IB/mlx4: Fix race condition between catas error reset and aliasguid flows Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 08/27] mmc: davinci: remove extraneous __init annotation Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 09/27] ALSA: opl3: fix mismatch between snd_opl3_drum_switch definition and declaration Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 10/27] thermal/int340x_thermal: Add additional UUIDs Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 11/27] thermal/int340x_thermal: fix mode setting Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 12/27] tools/power turbostat: return the exit status of a command Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 13/27] perf config: Fix an error in the config template documentation Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 14/27] perf config: Fix a memory leak in collect_config() Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 15/27] perf build-id: Fix memory leak in print_sdt_events() Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 16/27] perf top: Fix error handling in cmd_top() Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 17/27] perf hist: Add missing map__put() in error case Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 18/27] perf evsel: Free evsel->counts in perf_evsel__exit() Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 19/27] perf tests: Fix a memory leak of cpu_map object in the openat_syscall_event_on_all_cpus test Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 20/27] perf tests: Fix a memory leak in test__perf_evsel__tp_sched_test() Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 21/27] irqchip/mbigen: Don't clear eventid when freeing an MSI Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 22/27] x86/hpet: Prevent potential NULL pointer dereference Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 23/27] x86/cpu/cyrix: Use correct macros for Cyrix calls on Geode processors Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 24/27] iommu/vt-d: Check capability before disabling protected memory Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 25/27] x86/hw_breakpoints: Make default case in hw_breakpoint_arch_parse() return an error Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 26/27] fix incorrect error code mapping for OBJECTID_NOT_FOUND Sasha Levin
2019-03-30  0:55 ` [PATCH AUTOSEL 4.9 27/27] ext4: prohibit fstrim in norecovery mode Sasha Levin

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