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Commit c340b1d6 authored by Timo Warns's avatar Timo Warns Committed by Linus Torvalds
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fs/partitions/ldm.c: fix oops caused by corrupted partition table 



The kernel automatically evaluates partition tables of storage devices.
The code for evaluating LDM partitions (in fs/partitions/ldm.c) contains
a bug that causes a kernel oops on certain corrupted LDM partitions.
A kernel subsystem seems to crash, because, after the oops, the kernel no
longer recognizes newly connected storage devices.

The patch validates the value of vblk_size.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarTimo Warns <warns@pre-sense.de>
Cc: Eugene Teo <eugeneteo@kernel.sg>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Richard Russon <rich@flatcap.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c344180c

fs/partitions/ldm.c

+12 −4
Original line number Diff line number Diff line
@@ -1299,6 +1299,11 @@ static bool ldm_frag_add (const u8 *data, int size, struct list_head *frags) 


	BUG_ON (!data || !frags);



	if (size < 2 * VBLK_SIZE_HEAD) {

		ldm_error("Value of size is to small.");

		return false;

	}



	group = get_unaligned_be32(data + 0x08);

	rec   = get_unaligned_be16(data + 0x0C);

	num   = get_unaligned_be16(data + 0x0E);
@@ -1306,6 +1311,10 @@ static bool ldm_frag_add (const u8 *data, int size, struct list_head *frags) 
		ldm_error ("A VBLK claims to have %d parts.", num);

		return false;

	}

	if (rec >= num) {

		ldm_error("REC value (%d) exceeds NUM value (%d)", rec, num);

		return false;

	}



	list_for_each (item, frags) {

		f = list_entry (item, struct frag, list);
@@ -1334,10 +1343,9 @@ found: 


	f->map |= (1 << rec);



	if (num > 0) {

	data += VBLK_SIZE_HEAD;

	size -= VBLK_SIZE_HEAD;

	}



	memcpy (f->data+rec*(size-VBLK_SIZE_HEAD)+VBLK_SIZE_HEAD, data, size);



	return true;