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    Subject[PATCH 5.10 025/130] net: ethernet: dec: tulip: de4x5: fix possible array overflows in type3_infoblock()
    Date
    From: Teng Qi <starmiku1207184332@gmail.com>

    [ Upstream commit 0fa68da72c3be09e06dd833258ee89c33374195f ]

    The definition of macro MOTO_SROM_BUG is:
    #define MOTO_SROM_BUG (lp->active == 8 && (get_unaligned_le32(
    dev->dev_addr) & 0x00ffffff) == 0x3e0008)

    and the if statement
    if (MOTO_SROM_BUG) lp->active = 0;

    using this macro indicates lp->active could be 8. If lp->active is 8 and
    the second comparison of this macro is false. lp->active will remain 8 in:
    lp->phy[lp->active].gep = (*p ? p : NULL); p += (2 * (*p) + 1);
    lp->phy[lp->active].rst = (*p ? p : NULL); p += (2 * (*p) + 1);
    lp->phy[lp->active].mc = get_unaligned_le16(p); p += 2;
    lp->phy[lp->active].ana = get_unaligned_le16(p); p += 2;
    lp->phy[lp->active].fdx = get_unaligned_le16(p); p += 2;
    lp->phy[lp->active].ttm = get_unaligned_le16(p); p += 2;
    lp->phy[lp->active].mci = *p;

    However, the length of array lp->phy is 8, so array overflows can occur.
    To fix these possible array overflows, we first check lp->active and then
    return -EINVAL if it is greater or equal to ARRAY_SIZE(lp->phy) (i.e. 8).

    Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
    Signed-off-by: Teng Qi <starmiku1207184332@gmail.com>
    Reviewed-by: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/net/ethernet/dec/tulip/de4x5.c | 4 ++++
    1 file changed, 4 insertions(+)

    diff --git a/drivers/net/ethernet/dec/tulip/de4x5.c b/drivers/net/ethernet/dec/tulip/de4x5.c
    index ffc25ecfa8d6a..8edd394bc3358 100644
    --- a/drivers/net/ethernet/dec/tulip/de4x5.c
    +++ b/drivers/net/ethernet/dec/tulip/de4x5.c
    @@ -4706,6 +4706,10 @@ type3_infoblock(struct net_device *dev, u_char count, u_char *p)
    lp->ibn = 3;
    lp->active = *p++;
    if (MOTO_SROM_BUG) lp->active = 0;
    + /* if (MOTO_SROM_BUG) statement indicates lp->active could
    + * be 8 (i.e. the size of array lp->phy) */
    + if (WARN_ON(lp->active >= ARRAY_SIZE(lp->phy)))
    + return -EINVAL;
    lp->phy[lp->active].gep = (*p ? p : NULL); p += (2 * (*p) + 1);
    lp->phy[lp->active].rst = (*p ? p : NULL); p += (2 * (*p) + 1);
    lp->phy[lp->active].mc = get_unaligned_le16(p); p += 2;
    --
    2.33.0


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