From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Date: Sun, 29 Oct 2023 07:20:40 +0000 (+0100)
Subject: riscv: Fix an off-by-one in get_early_cmdline()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=adb1f95d388a43c4c564ef3e436f18900dde978e;p=linux.git

riscv: Fix an off-by-one in get_early_cmdline()

The ending NULL is not taken into account by strncat(), so switch to
strlcat() to correctly compute the size of the available memory when
appending CONFIG_CMDLINE to 'early_cmdline'.

Fixes: 26e7aacb83df ("riscv: Allow to downgrade paging mode from the command line")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/9f66d2b58c8052d4055e90b8477ee55d9a0914f9.1698564026.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---

diff --git a/arch/riscv/kernel/pi/cmdline_early.c b/arch/riscv/kernel/pi/cmdline_early.c
index 68e786c84c949..f6d4dedffb842 100644
--- a/arch/riscv/kernel/pi/cmdline_early.c
+++ b/arch/riscv/kernel/pi/cmdline_early.c
@@ -38,8 +38,7 @@ static char *get_early_cmdline(uintptr_t dtb_pa)
 	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
 	    IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
 	    fdt_cmdline_size == 0 /* CONFIG_CMDLINE_FALLBACK */) {
-		strncat(early_cmdline, CONFIG_CMDLINE,
-			COMMAND_LINE_SIZE - fdt_cmdline_size);
+		strlcat(early_cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 	}
 
 	return early_cmdline;