net: chelsio: cxgb4: Avoid potential negative array offset

Using min_t(int, ...) as a potential array index implies to the compiler
that negative offsets should be allowed. This is not the case, though.
Replace "int" with "unsigned int". Fixes the following warning exposed
under future CONFIG_FORTIFY_SOURCE improvements:

In file included from include/linux/string.h:253,
                 from include/linux/bitmap.h:11,
                 from include/linux/cpumask.h:12,
                 from include/linux/smp.h:13,
                 from include/linux/lockdep.h:14,
                 from include/linux/rcupdate.h:29,
                 from include/linux/rculist.h:11,
                 from include/linux/pid.h:5,
                 from include/linux/sched.h:14,
                 from include/linux/delay.h:23,
                 from drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:35:
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c: In function 't4_get_raw_vpd_params':
include/linux/fortify-string.h:46:33: warning: '__builtin_memcpy' pointer overflow between offset 29 and size [2147483648, 4294967295] [-Warray-bounds]
   46 | #define __underlying_memcpy     __builtin_memcpy
      |                                 ^
include/linux/fortify-string.h:388:9: note: in expansion of macro '__underlying_memcpy'
  388 |         __underlying_##op(p, q, __fortify_size);                        \
      |         ^~~~~~~~~~~~~
include/linux/fortify-string.h:433:26: note: in expansion of macro '__fortify_memcpy_chk'
  433 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
      |                          ^~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2796:9: note: in expansion of macro 'memcpy'
 2796 |         memcpy(p->id, vpd + id, min_t(int, id_len, ID_LEN));
      |         ^~~~~~
include/linux/fortify-string.h:46:33: warning: '__builtin_memcpy' pointer overflow between offset 0 and size [2147483648, 4294967295] [-Warray-bounds]
   46 | #define __underlying_memcpy     __builtin_memcpy
      |                                 ^
include/linux/fortify-string.h:388:9: note: in expansion of macro '__underlying_memcpy'
  388 |         __underlying_##op(p, q, __fortify_size);                        \
      |         ^~~~~~~~~~~~~
include/linux/fortify-string.h:433:26: note: in expansion of macro '__fortify_memcpy_chk'
  433 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
      |                          ^~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2798:9: note: in expansion of macro 'memcpy'
 2798 |         memcpy(p->sn, vpd + sn, min_t(int, sn_len, SERNUM_LEN));
      |         ^~~~~~

Additionally remove needless cast from u8[] to char * in last strim()
call.

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/202205031926.FVP7epJM-lkp@intel.com
Fixes: fc9279298e3a ("cxgb4: Search VPD with pci_vpd_find_ro_info_keyword()")
Fixes: 24c521f81c30 ("cxgb4: Use pci_vpd_find_id_string() to find VPD ID string")
Cc: Raju Rangoju <rajur@chelsio.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220505233101.1224230-1-keescook@chromium.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
index e7b4e3ed056c725cb832302c2efec6d0416a283d..8d719f82854a9d3acb582ba3b8af13479d29771d 100644 (file)
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
@@ -2793,14 +2793,14 @@ int t4_get_raw_vpd_params(struct adapter *adapter, struct vpd_params *p)
                goto out;
        na = ret;
 
-       memcpy(p->id, vpd + id, min_t(int, id_len, ID_LEN));
+       memcpy(p->id, vpd + id, min_t(unsigned int, id_len, ID_LEN));
        strim(p->id);
-       memcpy(p->sn, vpd + sn, min_t(int, sn_len, SERNUM_LEN));
+       memcpy(p->sn, vpd + sn, min_t(unsigned int, sn_len, SERNUM_LEN));
        strim(p->sn);
-       memcpy(p->pn, vpd + pn, min_t(int, pn_len, PN_LEN));
+       memcpy(p->pn, vpd + pn, min_t(unsigned int, pn_len, PN_LEN));
        strim(p->pn);
-       memcpy(p->na, vpd + na, min_t(int, na_len, MACADDR_LEN));
-       strim((char *)p->na);
+       memcpy(p->na, vpd + na, min_t(unsigned int, na_len, MACADDR_LEN));
+       strim(p->na);
 
 out:
        vfree(vpd);