Re: [PATCH 10/28] of/fdt: Replace strlcat() with snprintf() in early_init_dt_scan_chosen()
From: Rob Herring <robh@kernel.org>
Date: 2026-09-15 15:05:14
Also in:
dri-devel, intel-wired-lan, intel-xe, linux-edac, linux-gpio, linux-hardening, linux-input, linux-media, linux-mips, linux-nfs, linux-samsung-soc, linux-scsi, linux-sound, linux-wireless, lkml, loongarch, netdev
On Tue, Sep 15, 2026 at 08:18:27AM +0000, Bill Wendling wrote:
When CONFIG_CMDLINE_EXTEND is enabled, early_init_dt_scan_chosen() uses two strlcat() calls to append a space and CONFIG_CMDLINE to the command line buffer. In preparation for removing the deprecated strlcat() API[1], replace the strlcat() calls with a single snprintf() call using the existing string length. Additionally, check for a NULL initial_boot_params pointer and jump to "handle_cmdline" so that CONFIG_CMDLINE handling still occurs without dereferencing a NULL FDT pointer in fdt_path_offset(). Link: https://github.com/KSPP/linux/issues/370 [1] Cc: codemender-patching+linux@google.com Assisted-by: Assistant:Claude-3.5-Sonnet [editor_update_file, shell_command_run] Signed-off-by: Bill Wendling <morbo@google.com> ---
quoted hunk ↗ jump to hunk
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index a64afc3ded3d..311021a83f03 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c@@ -1095,6 +1095,9 @@ int __init early_init_dt_scan_chosen(char *cmdline) const void *rng_seed; const void *fdt = initial_boot_params; + if (!fdt) + goto handle_cmdline; + node = fdt_path_offset(fdt, "/chosen"); if (node < 0) node = fdt_path_offset(fdt, "/chosen@0");@@ -1133,8 +1136,12 @@ int __init early_init_dt_scan_chosen(char *cmdline) */ #ifdef CONFIG_CMDLINE #if defined(CONFIG_CMDLINE_EXTEND) - strlcat(cmdline, " ", COMMAND_LINE_SIZE); - strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); + {
No need for brackets.
+ size_t len = strlen(cmdline); + + if (len < COMMAND_LINE_SIZE) + snprintf(cmdline + len, COMMAND_LINE_SIZE - len, " %s", CONFIG_CMDLINE); + } #elif defined(CONFIG_CMDLINE_FORCE) strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE); #else -- 2.55.0.1032.g73a4cd73de-goog