kallsyms: Replace all non-returning strlcpy with strscpy

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230614010354.1026096-1-azeemshaikh38@gmail.com

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 7774739..ddb91d8 100644 (file)
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -716,7 +716,7 @@ static int get_ksymbol_bpf(struct kallsym_iter *iter)
 {
        int ret;
 
-       strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN);
+       strscpy(iter->module_name, "bpf", MODULE_NAME_LEN);
        iter->exported = 0;
        ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
                              &iter->value, &iter->type,
@@ -736,7 +736,7 @@ static int get_ksymbol_bpf(struct kallsym_iter *iter)
  */
 static int get_ksymbol_kprobe(struct kallsym_iter *iter)
 {
-       strlcpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
+       strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
        iter->exported = 0;
        return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,
                                  &iter->value, &iter->type,

diff --git a/kernel/params.c b/kernel/params.c
index 6a75489..07d01f6 100644 (file)
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -847,7 +847,7 @@ static void __init param_sysfs_builtin(void)
                        name_len = 0;
                } else {
                        name_len = dot - kp->name + 1;
-                       strlcpy(modname, kp->name, name_len);
+                       strscpy(modname, kp->name, name_len);
                }
                kernel_add_sysfs_param(modname, kp, name_len);
        }