When CONFIG_CMDLINE_BOOL is enabled without CONFIG_CMDLINE_OVERRIDE, setup_arch() appends boot_command_line to builtin_cmdline using two strlcat() calls before copying the result back to boot_command_line. In preparation for removing the deprecated strlcat() API[1], format the combined command line into a temporary buffer using a single snprintf() call and copy the result to both builtin_cmdline and boot_command_line. Using a temporary buffer avoids undefined behavior from passing overlapping source and destination buffers to snprintf(). Link: https://github.com/KSPP/linux/issues/370 [1] Cc: codemender-patching+linux@google.com Assisted-by: Developer:Gemini_2.5_Pro [editor_update_file, make_kernel_build_single_file, checkpatch_run] Signed-off-by: Bill Wendling --- Cc: Russell King Cc: Huacai Chen Cc: WANG Xuerui Cc: Thomas Bogendoerfer Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: Ian Abbott Cc: H Hartley Sweeten Cc: Tony Luck Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Simona Vetter Cc: Matthew Brost Cc: "Thomas Hellström" Cc: Rodrigo Vivi Cc: Dmitry Torokhov Cc: Matthias Schwarzott Cc: Mauro Carvalho Chehab Cc: Tony Nguyen Cc: Przemek Kitszel Cc: Andrew Lunn Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Arend van Spriel Cc: Rob Herring Cc: Saravana Kannan Cc: Krzysztof Kozlowski Cc: Sylwester Nawrocki Cc: Peter Griffin Cc: Alim Akhtar Cc: Linus Walleij Cc: Anil Gurumurthy Cc: Sudarsana Kalluru Cc: "Martin K. Petersen" Cc: Trond Myklebust Cc: Anna Schumaker Cc: Mike Marshall Cc: Martin Brandenburg Cc: Kees Cook Cc: Jiri Pirko Cc: Simon Horman Cc: Chuck Lever Cc: Jeff Layton Cc: NeilBrown Cc: Olga Kornievskaia Cc: Dai Ngo Cc: Tom Talpey Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Bill Wendling Cc: Andrew Morton Cc: "Mike Rapoport (Microsoft)" Cc: Kanglong Wang Cc: Tiezhu Yang Cc: Qiang Ma Cc: Randy Dunlap Cc: Pengpeng Hou Cc: Ard Biesheuvel Cc: Breno Leitao Cc: Thorsten Blum Cc: Harshit Mogalapalli Cc: Greg Kroah-Hartman Cc: Lyude Paul Cc: Ashutosh Desai Cc: Imre Deak Cc: Dmitry Baryshkov Cc: Johan Hovold Cc: Johannes Berg Cc: Miri Korenblit Cc: Alexander Stein Cc: Cryolitia PukNgae Cc: Jiaming Zhang Cc: Will Porter Cc: Cen Zhang Cc: "Cássio Gabriel" Cc: Rong Zhang Cc: Arun Raghavan Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: loongarch@lists.linux.dev Cc: linux-mips@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-edac@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: intel-xe@lists.freedesktop.org Cc: linux-input@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: intel-wired-lan@lists.osuosl.org Cc: netdev@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: brcm80211@lists.linux.dev Cc: brcm80211-dev-list.pdl@broadcom.com Cc: devicetree@vger.kernel.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: linux-nfs@vger.kernel.org Cc: devel@lists.orangefs.org Cc: linux-hardening@vger.kernel.org Cc: linux-sound@vger.kernel.org --- arch/x86/kernel/setup.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index cda6adb9f69c..c40e0edd7c13 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -916,9 +916,11 @@ void __init setup_arch(char **cmdline_p) #else if (builtin_cmdline[0]) { /* append boot loader cmdline to builtin */ - strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE); - strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE); - strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + char tmp[COMMAND_LINE_SIZE]; + + snprintf(tmp, COMMAND_LINE_SIZE, "%s %s", builtin_cmdline, boot_command_line); + strscpy(builtin_cmdline, tmp, COMMAND_LINE_SIZE); + strscpy(boot_command_line, tmp, COMMAND_LINE_SIZE); } #endif builtin_cmdline_added = true; -- 2.55.0.1032.g73a4cd73de-goog