kernel/sys.c: avoid copying possible padding bytes in copy_to_user

Initialization is not guaranteed to zero padding bytes so use an
explicit memset instead to avoid leaking any kernel content in any
possible padding bytes.

Link: http://lkml.kernel.org/r/dfa331c00881d61c8ee51577a082d8bebd61805c.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joe Perches 2019-12-04 16:50:53 -08:00 committed by Linus Torvalds
parent ef70eff9de
commit 5e1aada08c
1 changed files with 3 additions and 1 deletions

View File

@ -1279,11 +1279,13 @@ SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
{
struct oldold_utsname tmp = {};
struct oldold_utsname tmp;
if (!name)
return -EFAULT;
memset(&tmp, 0, sizeof(tmp));
down_read(&uts_sem);
memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);