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    Subject[PATCH 5.14 387/432] net: fix NULL pointer reference in cipso_v4_doi_free
    Date
    From: 王贇 <yun.wang@linux.alibaba.com>

    [ Upstream commit e842cb60e8ac1d8a15b01e0dd4dad453807a597d ]

    In netlbl_cipsov4_add_std() when 'doi_def->map.std' alloc
    failed, we sometime observe panic:

    BUG: kernel NULL pointer dereference, address:
    ...
    RIP: 0010:cipso_v4_doi_free+0x3a/0x80
    ...
    Call Trace:
    netlbl_cipsov4_add_std+0xf4/0x8c0
    netlbl_cipsov4_add+0x13f/0x1b0
    genl_family_rcv_msg_doit.isra.15+0x132/0x170
    genl_rcv_msg+0x125/0x240

    This is because in cipso_v4_doi_free() there is no check
    on 'doi_def->map.std' when doi_def->type got value 1, which
    is possibe, since netlbl_cipsov4_add_std() haven't initialize
    it before alloc 'doi_def->map.std'.

    This patch just add the check to prevent panic happen in similar
    cases.

    Reported-by: Abaci <abaci@linux.alibaba.com>
    Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/netlabel/netlabel_cipso_v4.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/net/netlabel/netlabel_cipso_v4.c b/net/netlabel/netlabel_cipso_v4.c
    index 000bb3da4f77..894e6b8f1a86 100644
    --- a/net/netlabel/netlabel_cipso_v4.c
    +++ b/net/netlabel/netlabel_cipso_v4.c
    @@ -144,8 +144,8 @@ static int netlbl_cipsov4_add_std(struct genl_info *info,
    return -ENOMEM;
    doi_def->map.std = kzalloc(sizeof(*doi_def->map.std), GFP_KERNEL);
    if (doi_def->map.std == NULL) {
    - ret_val = -ENOMEM;
    - goto add_std_failure;
    + kfree(doi_def);
    + return -ENOMEM;
    }
    doi_def->type = CIPSO_V4_MAP_TRANS;

    --
    2.30.2


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