From: Leo Stone leocstone@gmail.com
[ 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 --- security/safesetid/securityfs.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/security/safesetid/securityfs.c b/security/safesetid/securityfs.c index 25310468bcddf..8e1ffd70b18ab 100644 --- a/security/safesetid/securityfs.c +++ b/security/safesetid/securityfs.c @@ -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;