48 lines
1.7 KiB
Diff
48 lines
1.7 KiB
Diff
From 75e1c70fc31490ef8a373ea2a4bea2524099b478 Mon Sep 17 00:00:00 2001
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From: Jeff Moyer <jmoyer@redhat.com>
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Date: Fri, 10 Sep 2010 14:16:00 -0700
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Subject: [PATCH] aio: check for multiplication overflow in do_io_submit
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MIME-Version: 1.0
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Content-Type: text/plain; charset=utf8
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Content-Transfer-Encoding: 8bit
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Tavis Ormandy pointed out that do_io_submit does not do proper bounds
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checking on the passed-in iocb array:
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    if (unlikely(nr < 0))
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        return -EINVAL;
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    if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(iocbpp)))))
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        return -EFAULT;            ^^^^^^^^^^^^^^^^^^
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The attached patch checks for overflow, and if it is detected, the
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number of iocbs submitted is scaled down to a number that will fit in
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the long. Â This is an ok thing to do, as sys_io_submit is documented as
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returning the number of iocbs submitted, so callers should handle a
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return value of less than the 'nr' argument passed in.
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Reported-by: Tavis Ormandy <taviso@cmpxchg8b.com>
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Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/aio.c | 3 +++
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1 files changed, 3 insertions(+), 0 deletions(-)
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diff --git a/fs/aio.c b/fs/aio.c
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index 3006b5b..1320b2a 100644
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--- a/fs/aio.c
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+++ b/fs/aio.c
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@@ -1659,6 +1659,9 @@ long do_io_submit(aio_context_t ctx_id, long nr,
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if (unlikely(nr < 0))
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return -EINVAL;
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+ if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
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+ nr = LONG_MAX/sizeof(*iocbpp);
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+
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if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
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return -EFAULT;
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--
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1.7.2.3
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