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    Subject[PATCH 3.18 004/108] x86/PCI: Fix Broadcom CNB20LE unintended sign extension (redux)
    Date
    3.18-stable review patch.  If anyone has any objections, please let me know.

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

    [ Upstream commit 53bb565fc5439f2c8c57a786feea5946804aa3e9 ]

    In the expression "word1 << 16", word1 starts as u16, but is promoted to a
    signed int, then sign-extended to resource_size_t, which is probably not
    what was intended. Cast to resource_size_t to avoid the sign extension.

    This fixes an identical issue as fixed by commit 0b2d70764bb3 ("x86/PCI:
    Fix Broadcom CNB20LE unintended sign extension") back in 2014.

    Detected by CoverityScan, CID#138749, 138750 ("Unintended sign extension")

    Fixes: 3f6ea84a3035 ("PCI: read memory ranges out of Broadcom CNB20LE host bridge")
    Signed-off-by: Colin Ian King <colin.king@canonical.com>
    Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/x86/pci/broadcom_bus.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/pci/broadcom_bus.c b/arch/x86/pci/broadcom_bus.c
    index 526536c81ddc..ca1e8e6dccc8 100644
    --- a/arch/x86/pci/broadcom_bus.c
    +++ b/arch/x86/pci/broadcom_bus.c
    @@ -50,8 +50,8 @@ static void __init cnb20le_res(u8 bus, u8 slot, u8 func)
    word1 = read_pci_config_16(bus, slot, func, 0xc0);
    word2 = read_pci_config_16(bus, slot, func, 0xc2);
    if (word1 != word2) {
    - res.start = (word1 << 16) | 0x0000;
    - res.end = (word2 << 16) | 0xffff;
    + res.start = ((resource_size_t) word1 << 16) | 0x0000;
    + res.end = ((resource_size_t) word2 << 16) | 0xffff;
    res.flags = IORESOURCE_MEM;
    update_res(info, res.start, res.end, res.flags, 0);
    }
    --
    2.19.1


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