Messages in this thread Patch in this message | | | From | Sabyrzhan Tasbolatov <> | Subject | [PATCH] smackfs: restrict bytes count in smackfs write functions | Date | Sun, 24 Jan 2021 20:36:27 +0600 |
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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+a71a442385a0b2815497@syzkaller.appspotmail.com Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> --- 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)) -- 2.25.1
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