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.

Joe Perches committed 6 years ago

Commit 5e1aada1 parent ef70eff1 file · +3 −1Browse files

Showing the changes to kernel/sys.c (1 of 1 file). Show all

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kernel/sys.c+3−1

@@ -1279,11 +1279,13 @@ SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) · 1278 unmodified lines
1279	1279
1280	1280	SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1281	1281	{
1282		− struct oldold_utsname tmp = {};
	1282	+ struct oldold_utsname tmp;
1283	1283
1284	1284	if (!name)
1285	1285	return -EFAULT;
1286	1286
	1287	+ memset(&tmp, 0, sizeof(tmp));
	1288	+
1287	1289	down_read(&uts_sem);
1288	1290	memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
1289	1291	memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);