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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200528194905.690-3-tony.luck@intel.com>
Date:   Thu, 28 May 2020 12:49:05 -0700
From:   Tony Luck <tony.luck@...el.com>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Tony Luck <tony.luck@...el.com>,
        Lennart Poettering <mzxreary@...inter.de>,
        Matthew Garrett <matthew.garrett@...ula.com>,
        Jeremy Kerr <jk@...abs.org>, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] efivarfs: Don't return -EINTR when rate-limiting reads

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@...inter.de>
Signed-off-by: Tony Luck <tony.luck@...el.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