[PATCH 2/2] efivarfs: Don't return -EINTR when rate-limiting reads

From: Tony Luck <tony.luck@intel.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>,
	Lennart Poettering <mzxreary@0pointer.de>,
	Matthew Garrett <matthew.garrett@nebula.com>,
	Jeremy Kerr <jk@ozlabs.org>,
	linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] efivarfs: Don't return -EINTR when rate-limiting reads
Date: Thu, 28 May 2020 12:49:05 -0700	[thread overview]
Message-ID: <20200528194905.690-3-tony.luck@intel.com> (raw)
In-Reply-To: <20200528194905.690-1-tony.luck@intel.com>

Applications that read EFI variables may see a return
value of -EINTR if they exceed the rate limit and a
signal delivery is attempted while the process is sleeping.

This is quite surprising to the application, which probably
doesn't have code to handle it.

Change the interruptible sleep to a non-interruptible one.

Reported-by: Lennart Poettering <mzxreary@0pointer.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 fs/efivarfs/file.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index 4b8bc4560d70..feaa5e182b7b 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -73,10 +73,8 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 	ssize_t size = 0;
 	int err;
 
-	while (!__ratelimit(&file->f_cred->user->ratelimit)) {
-		if (!msleep_interruptible(50))
-			return -EINTR;
-	}
+	while (!__ratelimit(&file->f_cred->user->ratelimit))
+		msleep(50);
 
 	err = efivar_entry_size(var, &datasize);
 
-- 
2.21.1

