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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Darren Kenny <darren.kenny@oracle.com>
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Date: Tue, 8 Dec 2020 22:17:04 +0000
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Subject: [PATCH] zfs: Fix possible integer overflows
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In all cases the problem is that the value being acted upon by
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a left-shift is a 32-bit number which is then being used in the
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context of a 64-bit number.
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To avoid overflow we ensure that the number being shifted is 64-bit
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before the shift is done.
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Fixes: CID 73684, CID 73695, CID 73764
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Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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 grub-core/fs/zfs/zfs.c | 8 ++++----
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 1 file changed, 4 insertions(+), 4 deletions(-)
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diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c
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index 44d8bde6b..0d8c08eec 100644
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--- a/grub-core/fs/zfs/zfs.c
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+++ b/grub-core/fs/zfs/zfs.c
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@@ -564,7 +564,7 @@ find_bestub (uberblock_phys_t * ub_array,
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       ubptr = (uberblock_phys_t *) ((grub_properly_aligned_t *) ub_array
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 				    + ((i << ub_shift)
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 				       / sizeof (grub_properly_aligned_t)));
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-      err = uberblock_verify (ubptr, offset, 1 << ub_shift);
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+      err = uberblock_verify (ubptr, offset, (grub_size_t) 1 << ub_shift);
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       if (err)
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 	{
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 	  grub_errno = GRUB_ERR_NONE;
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@@ -1543,7 +1543,7 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
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 	    high = grub_divmod64 ((offset >> desc->ashift) + c,
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 				  desc->n_children, &devn);
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-	    csize = bsize << desc->ashift;
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+	    csize = (grub_size_t) bsize << desc->ashift;
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 	    if (csize > len)
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 	      csize = len;
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@@ -1635,8 +1635,8 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
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 	    while (len > 0)
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 	      {
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-		grub_size_t csize;
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-		csize = ((s / (desc->n_children - desc->nparity))
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+		grub_size_t csize = s;
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+		csize = ((csize / (desc->n_children - desc->nparity))
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 			 << desc->ashift);
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 		if (csize > len)
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 		  csize = len;