On 1/24/2021 6:36 AM, Sabyrzhan Tasbolatov wrote: > syzbot found WARNINGs in several smackfs write operations where > bytes count is passed to memdup_user_nul which exceeds > GFP MAX_ORDER. Check count size if bigger SMK_LONGLABEL, > for smk_write_syslog if bigger than PAGE_SIZE - 1. > > Reported-by: syzbot+a71a442385a0b2815...@syzkaller.appspotmail.com > Signed-off-by: Sabyrzhan Tasbolatov <snovit...@gmail.com>
Thank you for the patch. Unfortunately, SMK_LONGLABEL isn't the right value in some of these cases. > --- > security/smack/smackfs.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c > index 5d44b7d258ef..88678c6f1b8c 100644 > --- a/security/smack/smackfs.c > +++ b/security/smack/smackfs.c > @@ -1167,7 +1167,7 @@ static ssize_t smk_write_net4addr(struct file *file, > const char __user *buf, > return -EPERM; > if (*ppos != 0) > return -EINVAL; > - if (count < SMK_NETLBLADDRMIN) > + if (count < SMK_NETLBLADDRMIN || count > SMK_LONGLABEL) > return -EINVAL; > > data = memdup_user_nul(buf, count); > @@ -1427,7 +1427,7 @@ static ssize_t smk_write_net6addr(struct file *file, > const char __user *buf, > return -EPERM; > if (*ppos != 0) > return -EINVAL; > - if (count < SMK_NETLBLADDRMIN) > + if (count < SMK_NETLBLADDRMIN || count > SMK_LONGLABEL) > return -EINVAL; > > data = memdup_user_nul(buf, count); > @@ -2647,6 +2647,8 @@ static ssize_t smk_write_syslog(struct file *file, > const char __user *buf, > > if (!smack_privileged(CAP_MAC_ADMIN)) > return -EPERM; > + if (count > PAGE_SIZE - 1) > + return -EINVAL; > > data = memdup_user_nul(buf, count); > if (IS_ERR(data)) > @@ -2744,6 +2746,8 @@ static ssize_t smk_write_relabel_self(struct file > *file, const char __user *buf, > */ > if (*ppos != 0) > return -EINVAL; > + if (count > SMK_LONGLABEL) > + return -EINVAL; > > data = memdup_user_nul(buf, count); > if (IS_ERR(data))
