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Re: [PATCH] kernel 2.6.24.1 still vulnerable to the vmsplice local root exploit

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To: Niki Denev <ndenev@...>, Willy Tarreau <w@...>
Cc: <linux-kernel@...>, <jens.axboe@...>
Date: Sunday, February 10, 2008 - 8:22 am

On Sun, Feb 10, 2008 at 04:40:53AM -0500, Niki Denev wrote:

This patch is broken. It opens the old hole again.


iov is unchecked.


Use VERIFY_READ and this only checks the first entry.

I checked the following patch and it at least fixes the known exploit.

diff --git a/fs/splice.c b/fs/splice.c
index 14e2262..80beb2b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1237,6 +1237,11 @@ static int get_iovec_page_array(const struct iovec __user *iov,
 		if (unlikely(!base))
 			break;
 
+		if (!access_ok(VERIFY_READ, base, len)) {
+			error = -EFAULT;
+			break;
+		}
+
 		/*
 		 * Get this base offset and number of pages, then map
 		 * in the user pages.
-- 
Even historians fail to learn from history -- they repeat the same mistakes.
		-- John Gill, "Patterns of Force", stardate 2534.7
--
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Re: [PATCH] kernel 2.6.24.1 still vulnerable to the vmsplice..., Bastian Blank, (Sun Feb 10, 8:22 am)
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