[PATCH] ARM: Replace all non-returning strlcpy with strscpy

Azeem Shaikh
2023-05-30T15:55:39Z

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>
---
arch/arm/kernel/atags_parse.c | 4 ++--
arch/arm/kernel/setup.c | 2 +-
arch/arm/kernel/vdso.c | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c
index 373b61f9a4f0..33f6eb5213a5 100644
--- a/arch/arm/kernel/atags_parse.c
+++ b/arch/arm/kernel/atags_parse.c
@@ -127,7 +127,7 @@ static int __init parse_tag_cmdline(const struct tag *tag)
#elif defined(CONFIG_CMDLINE_FORCE)
pr_warn("Ignoring tag cmdline (using the default kernel command line)\n");
#else
- strlcpy(default_command_line, tag->u.cmdline.cmdline,
+ strscpy(default_command_line, tag->u.cmdline.cmdline,
COMMAND_LINE_SIZE);
#endif
return 0;
@@ -224,7 +224,7 @@ setup_machine_tags(void *atags_vaddr, unsigned int machine_nr)
}

/* parse_early_param needs a boot_command_line */
- strlcpy(boot_command_line, from, COMMAND_LINE_SIZE);
+ strscpy(boot_command_line, from, COMMAND_LINE_SIZE);

return mdesc;
}
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 75cd4699e7b3..3048a685ea79 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1142,7 +1142,7 @@ void __init setup_arch(char **cmdline_p)
setup_initial_init_mm(_text, _etext, _edata, _end);

/* populate cmd_line too for later use, preserving boot_command_line */
- strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
+ strscpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = cmd_line;

early_fixmap_init();
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 3408269d19c7..f297d66a8a76 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -135,7 +135,7 @@ static Elf32_Sym * __init find_symbol(struct elfinfo *lib, const char *symname)

if (lib->dynsym[i].st_name == 0)
continue;
- strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
+ strscpy(name, lib->dynstr + lib->dynsym[i].st_name,
MAX_SYMNAME);
c = strchr(name, '@');
if (c)