Commit 5e1aada0 authored Dec 04, 2019 by Joe Perches Committed by Linus Torvalds Dec 04, 2019

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>

parent ef70eff9

kernel/sys.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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);

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