linux-kernel - [PATCH] efi/esrt: Allow ESRT access without CAP_SYS

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-next>] [day] [month] [year] [list]

Date:   Fri, 12 May 2023 19:43:02 +0000
From:   Nicholas Bishop <nicholasbishop@...gle.com>
To:     Ard Biesheuvel <ardb@...nel.org>, linux-efi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Peter Jones <pjones@...hat.com>,
        Nicholas Bishop <nicholasbishop@...gle.com>
Subject: [PATCH] efi/esrt: Allow ESRT access without CAP_SYS_ADMIN

Access to the files in /sys/firmware/efi/esrt has been restricted to
CAP_SYS_ADMIN since support for ESRT was added, but this seems overly
restrictive given that the files are read-only and just provide
information about UEFI firmware updates.

Remove the CAP_SYS_ADMIN restriction so that a non-root process can read
the files, provided a suitably-privileged process changes the file
ownership first. The files are still read-only and still owned by root by
default.

Signed-off-by: Nicholas Bishop <nicholasbishop@...gle.com>
---
 drivers/firmware/efi/esrt.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
index d5915272141f..aab96ab64a1a 100644
--- a/drivers/firmware/efi/esrt.c
+++ b/drivers/firmware/efi/esrt.c
@@ -95,10 +95,6 @@ static ssize_t esre_attr_show(struct kobject *kobj,
 	struct esre_entry *entry = to_entry(kobj);
 	struct esre_attribute *attr = to_attr(_attr);

-	/* Don't tell normal users what firmware versions we've got... */
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-
 	return attr->show(entry, buf);
 }

-- 
2.40.1.606.ga4b1b128d6-goog