| Message ID | 20231002124856.2455696-3-andriy.shevchenko@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | params: harden string ops and allocatio ops | expand |
On Mon, Oct 02, 2023 at 03:48:53PM +0300, Andy Shevchenko wrote: > We can use strnlen() even on early stages and it prevents from > going over the string boundaries in case it's already too long. It makes sense to avoid calling strlen() multiple times. I don't have much opinion one way or another about using strnlen() here, since we know the string will be terminated. -Kees > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > kernel/params.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/kernel/params.c b/kernel/params.c > index 626fa8265932..f8e3c4139854 100644 > --- a/kernel/params.c > +++ b/kernel/params.c > @@ -260,7 +260,10 @@ EXPORT_SYMBOL_GPL(param_set_uint_minmax); > > int param_set_charp(const char *val, const struct kernel_param *kp) > { > - if (strlen(val) > 1024) { > + size_t len, maxlen = 1024; > + > + len = strnlen(val, maxlen + 1); > + if (len == maxlen + 1) { > pr_err("%s: string parameter too long\n", kp->name); > return -ENOSPC; > } > @@ -270,7 +273,7 @@ int param_set_charp(const char *val, const struct kernel_param *kp) > /* This is a hack. We can't kmalloc in early boot, and we > * don't need to; this mangled commandline is preserved. */ > if (slab_is_available()) { > - *(char **)kp->arg = kmalloc_parameter(strlen(val)+1); > + *(char **)kp->arg = kmalloc_parameter(len + 1); > if (!*(char **)kp->arg) > return -ENOMEM; > strcpy(*(char **)kp->arg, val); > @@ -508,7 +511,7 @@ int param_set_copystring(const char *val, const struct kernel_param *kp) > { > const struct kparam_string *kps = kp->str; > > - if (strlen(val)+1 > kps->maxlen) { > + if (strnlen(val, kps->maxlen) == kps->maxlen) { > pr_err("%s: string doesn't fit in %u chars.\n", > kp->name, kps->maxlen-1); > return -ENOSPC; > -- > 2.40.0.1.gaa8946217a0b >
diff --git a/kernel/params.c b/kernel/params.c index 626fa8265932..f8e3c4139854 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -260,7 +260,10 @@ EXPORT_SYMBOL_GPL(param_set_uint_minmax); int param_set_charp(const char *val, const struct kernel_param *kp) { - if (strlen(val) > 1024) { + size_t len, maxlen = 1024; + + len = strnlen(val, maxlen + 1); + if (len == maxlen + 1) { pr_err("%s: string parameter too long\n", kp->name); return -ENOSPC; } @@ -270,7 +273,7 @@ int param_set_charp(const char *val, const struct kernel_param *kp) /* This is a hack. We can't kmalloc in early boot, and we * don't need to; this mangled commandline is preserved. */ if (slab_is_available()) { - *(char **)kp->arg = kmalloc_parameter(strlen(val)+1); + *(char **)kp->arg = kmalloc_parameter(len + 1); if (!*(char **)kp->arg) return -ENOMEM; strcpy(*(char **)kp->arg, val); @@ -508,7 +511,7 @@ int param_set_copystring(const char *val, const struct kernel_param *kp) { const struct kparam_string *kps = kp->str; - if (strlen(val)+1 > kps->maxlen) { + if (strnlen(val, kps->maxlen) == kps->maxlen) { pr_err("%s: string doesn't fit in %u chars.\n", kp->name, kps->maxlen-1); return -ENOSPC;
We can use strnlen() even on early stages and it prevents from going over the string boundaries in case it's already too long. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- kernel/params.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)