safesetid: check size of policy writes

BugLink: https://bugs.launchpad.net/bugs/2114239

[ Upstream commit f09ff307c7299392f1c88f763299e24bc99811c7 ]

syzbot attempts to write a buffer with a large size to a sysfs entry
with writes handled by handle_policy_update(), triggering a warning
in kmalloc.

Check the size specified for write buffers before allocating.

Reported-by: syzbot+4eb7a741b3216020043a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=4eb7a741b3216020043a
Signed-off-by: Leo Stone <leocstone@gmail.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Noah Wager <noah.wager@canonical.com>
Signed-off-by: Mehmet Basaran <mehmet.basaran@canonical.com>

This commit is contained in:

Leo Stone

2024-12-17 10:26:57 -08:00

committed by

Mehmet Basaran

parent c173cc526c

commit c62f6888a9

1 changed files with 3 additions and 0 deletions

									
										security/safesetid/securityfs.c
									
		+3
		
												View File
												
				@@ -143,6 +143,9 @@ static ssize_t handle_policy_update(struct file *file,

					char *buf, *p, *end;

					int err;

					if (len >= KMALLOC_MAX_SIZE)

						return -EINVAL;

					pol = kmalloc(sizeof(struct setid_ruleset), GFP_KERNEL);

					if (!pol)

						return -ENOMEM;