lkml.org 
[lkml]   [2012]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[34-longterm 127/196] Fix corrupted OSF partition table parsing
    Date
    From: Timo Warns <Warns@pre-sense.de>

    -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
    -------------------

    commit 1eafbfeb7bdf59cfe173304c76188f3fd5f1fd05 upstream.

    The kernel automatically evaluates partition tables of storage devices.
    The code for evaluating OSF partitions contains a bug that leaks data
    from kernel heap memory to userspace for certain corrupted OSF
    partitions.

    In more detail:

    for (i = 0 ; i < le16_to_cpu(label->d_npartitions); i++, partition++) {

    iterates from 0 to d_npartitions - 1, where d_npartitions is read from
    the partition table without validation and partition is a pointer to an
    array of at most 8 d_partitions.

    Add the proper and obvious validation.

    Signed-off-by: Timo Warns <warns@pre-sense.de>
    [ Changed the patch trivially to not repeat the whole le16_to_cpu()
    thing, and to use an explicit constant for the magic value '8' ]
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

    Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
    ---
    fs/partitions/osf.c | 12 ++++++++++--
    1 file changed, 10 insertions(+), 2 deletions(-)

    diff --git a/fs/partitions/osf.c b/fs/partitions/osf.c
    index c05c17bc..6e0825e 100644
    --- a/fs/partitions/osf.c
    +++ b/fs/partitions/osf.c
    @@ -10,10 +10,13 @@
    #include "check.h"
    #include "osf.h"

    +#define MAX_OSF_PARTITIONS 8
    +
    int osf_partition(struct parsed_partitions *state, struct block_device *bdev)
    {
    int i;
    int slot = 1;
    + unsigned int npartitions;
    Sector sect;
    unsigned char *data;
    struct disklabel {
    @@ -45,7 +48,7 @@ int osf_partition(struct parsed_partitions *state, struct block_device *bdev)
    u8 p_fstype;
    u8 p_frag;
    __le16 p_cpg;
    - } d_partitions[8];
    + } d_partitions[MAX_OSF_PARTITIONS];
    } * label;
    struct d_partition * partition;

    @@ -63,7 +66,12 @@ int osf_partition(struct parsed_partitions *state, struct block_device *bdev)
    put_dev_sector(sect);
    return 0;
    }
    - for (i = 0 ; i < le16_to_cpu(label->d_npartitions); i++, partition++) {
    + npartitions = le16_to_cpu(label->d_npartitions);
    + if (npartitions > MAX_OSF_PARTITIONS) {
    + put_dev_sector(sect);
    + return 0;
    + }
    + for (i = 0 ; i < npartitions; i++, partition++) {
    if (slot == state->limit)
    break;
    if (le32_to_cpu(partition->p_size))
    --
    1.7.9.3


    \
     
     \ /
      Last update: 2012-03-13 01:27    [W:0.059 / U:0.220 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site