On Wed, Sep 27, 2023 at 05:37:06AM +0000, Justin Stitt wrote: > A malloc + strncpy + manual NUL_termination is just kmemdup_nul. Let's use > this interface as it is less error-prone and more readable. > > Also drop `csraddr_len` as it is just used in a single place and we can > just do the arithmetic in-line. > > Link: > https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings > [1] > Link: https://github.com/KSPP/linux/issues/90 > Cc: [email protected] > Cc: Kees Cook <[email protected]> > Signed-off-by: Justin Stitt <[email protected]>
Yup, this looks correct to me. Another good case of using kmemdup_nul(). Reviewed-by: Kees Cook <[email protected]> > --- > Note: build-tested only. > --- > drivers/misc/eeprom/idt_89hpesx.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > > diff --git a/drivers/misc/eeprom/idt_89hpesx.c > b/drivers/misc/eeprom/idt_89hpesx.c > index 1d1f30b5c426..d807d08e2614 100644 > --- a/drivers/misc/eeprom/idt_89hpesx.c > +++ b/drivers/misc/eeprom/idt_89hpesx.c > @@ -905,7 +905,7 @@ static ssize_t idt_dbgfs_csr_write(struct file *filep, > const char __user *ubuf, > { > struct idt_89hpesx_dev *pdev = filep->private_data; > char *colon_ch, *csraddr_str, *csrval_str; > - int ret, csraddr_len; > + int ret; > u32 csraddr, csrval; > char *buf; > > @@ -927,21 +927,16 @@ static ssize_t idt_dbgfs_csr_write(struct file *filep, > const char __user *ubuf, > * no new CSR value > */ > if (colon_ch != NULL) { > - csraddr_len = colon_ch - buf; > - csraddr_str = > - kmalloc(csraddr_len + 1, GFP_KERNEL); > + /* Copy the register address to the substring buffer */ > + csraddr_str = kmemdup_nul(buf, colon_ch - buf, GFP_KERNEL); > if (csraddr_str == NULL) { > ret = -ENOMEM; > goto free_buf; > } > - /* Copy the register address to the substring buffer */ > - strncpy(csraddr_str, buf, csraddr_len); > - csraddr_str[csraddr_len] = '\0'; > /* Register value must follow the colon */ > csrval_str = colon_ch + 1; > } else /* if (str_colon == NULL) */ { > csraddr_str = (char *)buf; /* Just to shut warning up */ > - csraddr_len = strnlen(csraddr_str, count); > csrval_str = NULL; > } > > > --- > base-commit: 6465e260f48790807eef06b583b38ca9789b6072 > change-id: 20230927-strncpy-drivers-misc-eeprom-idt_89hpesx-c-b09ed5507b7d > > Best regards, > -- > Justin Stitt <[email protected]> > -- Kees Cook
