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    Subject[PATCH 13/91] fs/partitions/ldm.c: fix oops caused by corrupted partition table
    2.6.27-longterm review patch.  If anyone has any objections, please let us know.

    ------------------

    commit c340b1d640001c8c9ecff74f68fd90422ae2448a upstream.

    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: Timo 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: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    ---
    fs/partitions/ldm.c | 16 ++++++++++++----
    1 files changed, 12 insertions(+), 4 deletions(-)

    Index: longterm-2.6.27/fs/partitions/ldm.c
    ===================================================================
    --- longterm-2.6.27.orig/fs/partitions/ldm.c 2012-02-05 22:34:34.635914935 +0100
    +++ longterm-2.6.27/fs/partitions/ldm.c 2012-02-05 22:34:36.759915873 +0100
    @@ -1299,6 +1299,11 @@

    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 @@
    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 @@

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

    - if (num > 0) {
    - data += VBLK_SIZE_HEAD;
    - size -= VBLK_SIZE_HEAD;
    - }
    + data += VBLK_SIZE_HEAD;
    + size -= VBLK_SIZE_HEAD;
    +
    memcpy (f->data+rec*(size-VBLK_SIZE_HEAD)+VBLK_SIZE_HEAD, data, size);

    return true;



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