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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Thu,  6 Aug 2020 17:49:04 -0700
From:   Guenter Roeck <>
To:     Linus Torvalds <>
Cc:     Catalin Marinas <>,
        Will Deacon <>,,,
        Daniel Díaz <>,, Guenter Roeck <>,
        Qian Cai <>, Mark Brown <>
Subject: [PATCH] arm64: kaslr: Use standard early random function

Commit 585524081ecd ("random: random.h should include archrandom.h, not
the other way around") tries to fix a problem with recursive inclusion
of linux/random.h and arch/archrandom.h for arm64. Unfortunately, this
results in the following compile error if ARCH_RANDOM is disabled.

arch/arm64/kernel/kaslr.c: In function 'kaslr_early_init':
arch/arm64/kernel/kaslr.c:128:6: error: implicit declaration of function
'__early_cpu_has_rndr'; did you mean '__early_pfn_to_nid'?
  if (__early_cpu_has_rndr()) {
arch/arm64/kernel/kaslr.c:131:7: error: implicit declaration of function
'__arm64_rndr' [-Werror=implicit-function-declaration]
   if (__arm64_rndr(&raw))

Problem is that arch/archrandom.h is only included from linux/random.h if
ARCH_RANDOM is enabled. If not, __arm64_rndr() and __early_cpu_has_rndr()
are undeclared, causing the problem.

Use arch_get_random_seed_long_early() instead of arm64 specific functions
to solve the problem. As a side effect of this change, the code no longer
bypasses ARCH_RANDOM, which I consider desirable (after all, ARCH_RANDOM
was disabled for a reason).

Reported-by: Qian Cai <>
Fixes: 585524081ecd ("random: random.h should include archrandom.h, not the other way around")
Fixes: 2e8e1ea88cbc ("arm64: Use v8.5-RNG entropy for KASLR seed")
Cc: Qian Cai <>
Cc: Mark Brown <>
Signed-off-by: Guenter Roeck <>
 arch/arm64/kernel/kaslr.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index 9ded4237e1c1..b181e0544b79 100644
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -84,6 +84,7 @@ u64 __init kaslr_early_init(u64 dt_phys)
 	void *fdt;
 	u64 seed, offset, mask, module_range;
 	const u8 *cmdline, *str;
+	unsigned long raw;
 	int size;
@@ -122,15 +123,12 @@ u64 __init kaslr_early_init(u64 dt_phys)
-	 * Mix in any entropy obtainable architecturally, open coded
-	 * since this runs extremely early.
+	 * Mix in any entropy obtainable architecturally if enabled
+	 * and supported.
-	if (__early_cpu_has_rndr()) {
-		unsigned long raw;
-		if (__arm64_rndr(&raw))
-			seed ^= raw;
-	}
+	if (arch_get_random_seed_long_early(&raw))
+		seed ^= raw;
 	if (!seed) {
 		kaslr_status = KASLR_DISABLED_NO_SEED;

Powered by blists - more mailing lists