Btrfs: fix an integer overflow check

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[ Upstream commit 457ae7268b ]

This isn't super serious because you need CAP_ADMIN to run this code.

I added this integer overflow check last year but apparently I am
rubbish at writing integer overflow checks...  There are two issues.
First, access_ok() works on unsigned long type and not u64 so on 32 bit
systems the access_ok() could be checking a truncated size.  The other
issue is that we should be using a stricter limit so we don't overflow
the kzalloc() setting ctx->clone_roots later in the function after the
access_ok():

	alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
	sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN);

Fixes: f5ecec3ce2 ("btrfs: send: silence an integer overflow warning")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ added comment ]
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Dan Carpenter 2017-03-17 23:51:20 +03:00 • committed by Greg Kroah-Hartman

parent 0708a47681

commit 9c1433b5dd

1 changed files with 6 additions and 1 deletions

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fs/btrfs/send.c

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