Message ID | 20210807071427.59613-1-wangborong@cdjrlc.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | riscv: use strscpy to replace strlcpy | expand |
On Sat, 07 Aug 2021 00:14:27 PDT (-0700), wangborong@cdjrlc.com wrote: > The strlcpy should not be used because it doesn't limit the source > length. As linus says, it's a completely useless function if you > can't implicitly trust the source string - but that is almost always > why people think they should use it! All in all the BSD function > will lead some potential bugs. > > But the strscpy doesn't require reading memory from the src string > beyond the specified "count" bytes, and since the return value is > easier to error-check than strlcpy()'s. In addition, the implementation > is robust to the string changing out from underneath it, unlike the > current strlcpy() implementation. > > Thus, We prefer using strscpy instead of strlcpy. > > Signed-off-by: Jason Wang <wangborong@cdjrlc.com> > --- > arch/riscv/kernel/setup.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c > index 18bd0e4bc36c..2dc62ebc0001 100644 > --- a/arch/riscv/kernel/setup.c > +++ b/arch/riscv/kernel/setup.c > @@ -255,7 +255,7 @@ static void __init parse_dtb(void) > > pr_err("No DTB passed to the kernel\n"); > #ifdef CONFIG_CMDLINE_FORCE > - strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); > + strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); > pr_info("Forcing kernel command line to: %s\n", boot_command_line); > #endif > } Thanks, this is on for-next.
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 18bd0e4bc36c..2dc62ebc0001 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -255,7 +255,7 @@ static void __init parse_dtb(void) pr_err("No DTB passed to the kernel\n"); #ifdef CONFIG_CMDLINE_FORCE - strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); + strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); pr_info("Forcing kernel command line to: %s\n", boot_command_line); #endif }
The strlcpy should not be used because it doesn't limit the source length. As linus says, it's a completely useless function if you can't implicitly trust the source string - but that is almost always why people think they should use it! All in all the BSD function will lead some potential bugs. But the strscpy doesn't require reading memory from the src string beyond the specified "count" bytes, and since the return value is easier to error-check than strlcpy()'s. In addition, the implementation is robust to the string changing out from underneath it, unlike the current strlcpy() implementation. Thus, We prefer using strscpy instead of strlcpy. Signed-off-by: Jason Wang <wangborong@cdjrlc.com> --- arch/riscv/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)