Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH] kobject: Replace strlcpy with strscpy | Date | Mon, 10 Jul 2023 13:13:06 +0000 |
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From: Azeem Shaikh > Sent: 03 July 2023 19:05 > > 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(). > > Direct replacement is safe here since return value of -errno > is used to check for truncation instead of sizeof(dest). > > [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> > --- > lib/kobject_uevent.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c > index 7c44b7ae4c5c..e5497fa0a2d2 100644 > --- a/lib/kobject_uevent.c > +++ b/lib/kobject_uevent.c > @@ -254,8 +254,8 @@ static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) > int buffer_size = sizeof(env->buf) - env->buflen; > int len; > > - len = strlcpy(&env->buf[env->buflen], subsystem, buffer_size); > - if (len >= buffer_size) { > + len = strscpy(&env->buf[env->buflen], subsystem, buffer_size); > + if (len < 0) { > pr_warn("init_uevent_argv: buffer size of %d too small, needed %d\n", > buffer_size, len); > return -ENOMEM;
The size in the error message is now wrong. It has to be said that mostly all the strings that get copied in the kernel are '\0' terminated - so maybe it is all moot. OTOH printing (at least some of) the string that didn't fit is a lot more useful than its length.
David
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