[dpdk-dev] [Bug 838] [ubsan] bnxt: left shift cannot be represented in bnxt_hwrm_ver_get()

[bugzilla at dpdk.org]

https://bugs.dpdk.org/show_bug.cgi?id=838

            Bug ID: 838
           Summary: [ubsan] bnxt: left shift cannot be represented in
                    bnxt_hwrm_ver_get()
           Product: DPDK
           Version: unspecified
          Hardware: All
                OS: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: ethdev
          Assignee: dev at dpdk.org
          Reporter: burner-email at caramail.com
  Target Milestone: ---

Hello,

An issue found by UBSan:

DPDK/drivers/net/bnxt/bnxt_hwrm.c:X:Y: runtime error: left shift of 216 by 24
places cannot be represented in type 'int'.

The offending code is in bnxt_hwrm_ver_get():

        bp->fw_ver = (resp->hwrm_fw_maj_8b << 24) |   <--- HERE
                     (resp->hwrm_fw_min_8b << 16) |
                     (resp->hwrm_fw_bld_8b << 8) |
                     resp->hwrm_fw_rsvd_8b;

The left shifts here are of type 'int', and the first one cannot be
represented. This is an undefined behavior.

The first shift should be explicitly cast to uint32_t, ie:

        bp->fw_ver = ((uint32_t)resp->hwrm_fw_maj_8b << 24) |
                     (resp->hwrm_fw_min_8b << 16) |
                     (resp->hwrm_fw_bld_8b << 8) |
                     resp->hwrm_fw_rsvd_8b;

I have tested this patch, and could confirm with UBSan that there is no
undefined behavior anymore.

Thanks!

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