From:   Takashi Iwai <tiwai@suse.de>
To:     Dinh Nguyen <dinguyen@kernel.org>
Cc:     Kees Cook <keescook@chromium.org>,
        "Ivan T . Ivanov" <iivanov@suse.de>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] ARM: socfpga: Fix crash with CONFIG_FORTIRY_SOURCE
Date:   Thu, 18 Nov 2021 15:25:08 +0100
Message-Id: <20211118142508.19200-1-tiwai@suse.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When CONFIG_FORTIFY_SOURCE is set, memcpy() checks the potential
buffer overflow and panics.  The code in sofcpga bootstrapping
contains the memcpy() calls are mistakenly translated as the shorter
size, hence it triggers a panic as if it were overflowing.

This patch changes the secondary_trampoline and *_end definitions
to arrays for avoiding the false-positive crash above.

Suggested-by: Kees Cook <keescook@chromium.org>
Buglink: https://bugzilla.suse.com/show_bug.cgi?id=1192473
Link: https://lore.kernel.org/r/20211117193244.31162-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

v1->v2: Use arrays for trampoline area instead of hackish workaround
	with __NO_FORTIFY

 arch/arm/mach-socfpga/core.h    | 2 +-
 arch/arm/mach-socfpga/platsmp.c | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-socfpga/core.h b/arch/arm/mach-socfpga/core.h
index fc2608b18a0d..18f01190dcfd 100644
--- a/arch/arm/mach-socfpga/core.h
+++ b/arch/arm/mach-socfpga/core.h
@@ -33,7 +33,7 @@ extern void __iomem *sdr_ctl_base_addr;
 u32 socfpga_sdram_self_refresh(u32 sdr_base);
 extern unsigned int socfpga_sdram_self_refresh_sz;
 
-extern char secondary_trampoline, secondary_trampoline_end;
+extern char secondary_trampoline[], secondary_trampoline_end[];
 
 extern unsigned long socfpga_cpu1start_addr;
 
diff --git a/arch/arm/mach-socfpga/platsmp.c b/arch/arm/mach-socfpga/platsmp.c
index fbb80b883e5d..201191cf68f3 100644
--- a/arch/arm/mach-socfpga/platsmp.c
+++ b/arch/arm/mach-socfpga/platsmp.c
@@ -20,14 +20,14 @@
 
 static int socfpga_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
-	int trampoline_size = &secondary_trampoline_end - &secondary_trampoline;
+	int trampoline_size = secondary_trampoline_end - secondary_trampoline;
 
 	if (socfpga_cpu1start_addr) {
 		/* This will put CPU #1 into reset. */
 		writel(RSTMGR_MPUMODRST_CPU1,
 		       rst_manager_base_addr + SOCFPGA_RSTMGR_MODMPURST);
 
-		memcpy(phys_to_virt(0), &secondary_trampoline, trampoline_size);
+		memcpy(phys_to_virt(0), secondary_trampoline, trampoline_size);
 
 		writel(__pa_symbol(secondary_startup),
 		       sys_manager_base_addr + (socfpga_cpu1start_addr & 0x000000ff));
@@ -45,12 +45,12 @@ static int socfpga_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
 static int socfpga_a10_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
-	int trampoline_size = &secondary_trampoline_end - &secondary_trampoline;
+	int trampoline_size = secondary_trampoline_end - secondary_trampoline;
 
 	if (socfpga_cpu1start_addr) {
 		writel(RSTMGR_MPUMODRST_CPU1, rst_manager_base_addr +
 		       SOCFPGA_A10_RSTMGR_MODMPURST);
-		memcpy(phys_to_virt(0), &secondary_trampoline, trampoline_size);
+		memcpy(phys_to_virt(0), secondary_trampoline, trampoline_size);
 
 		writel(__pa_symbol(secondary_startup),
 		       sys_manager_base_addr + (socfpga_cpu1start_addr & 0x00000fff));
-- 
2.26.2