Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
RDMA: Add ib_respond_udata()
Wrap the common copy_to_user() pattern used in drivers and enhance it
to zero pad as well. Include debug logging on failures.
Link: https://patch.msgid.link/r/5-v3-bd56dd443069+49-bnxt_re_uapi_jgg@nvidia.com
Tested-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Acked-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
+57
+24
drivers/infiniband/core/uverbs_ioctl.c
+24
drivers/infiniband/core/uverbs_ioctl.c
···
910
910
return -EOPNOTSUPP;
911
911
}
912
912
EXPORT_SYMBOL(_ib_copy_validate_udata_cm_fail);
913
+
914
+
int _ib_respond_udata(struct ib_udata *udata, const void *src, size_t len)
915
+
{
916
+
size_t copy_len;
917
+
918
+
/* 0 length copy_len is a NOP for copy_to_user() and doesn't fail. */
919
+
copy_len = min(len, udata->outlen);
920
+
if (copy_to_user(udata->outbuf, src, copy_len))
921
+
goto err_fault;
922
+
if (copy_len < udata->outlen) {
923
+
if (clear_user(udata->outbuf + copy_len,
924
+
udata->outlen - copy_len))
925
+
goto err_fault;
926
+
}
927
+
return 0;
928
+
err_fault:
929
+
ibdev_dbg(
930
+
rdma_udata_to_dev(udata),
931
+
"System call driver out udata has EFAULT (%zu into %zu) for ioctl %ps called by %pSR\n",
932
+
len, udata->outlen, uverbs_get_handler_fn(udata),
933
+
__builtin_return_address(0));
934
+
return -EFAULT;
935
+
}
936
+
EXPORT_SYMBOL(_ib_respond_udata);
+33
include/rdma/uverbs_ioctl.h
+33
include/rdma/uverbs_ioctl.h
···
900
900
901
901
int _ib_copy_validate_udata_in(struct ib_udata *udata, void *req,
902
902
size_t kernel_size, size_t minimum_size);
903
+
int _ib_respond_udata(struct ib_udata *udata, const void *src, size_t len);
903
904
#else
904
905
static inline int
905
906
uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
···
965
964
return -EINVAL;
966
965
}
967
966
967
+
static inline int _ib_respond_udata(struct ib_udata *udata, const void *src,
968
+
size_t len)
969
+
{
970
+
return -EINVAL;
971
+
}
968
972
#endif
969
973
970
974
#define uverbs_get_const_signed(_to, _attrs_bundle, _idx) \
···
1074
1068
_udata, (_req).comp_mask, __valid_cm); \
1075
1069
ret; \
1076
1070
})
1071
+
1072
+
/**
1073
+
* ib_respond_udata - Copy a driver data response to userspace
1074
+
* @_udata: The system calls ib_udata struct
1075
+
* @_rep: Kernel buffer containing the response driver data on the stack
1076
+
*
1077
+
* Copy driver data response structures back to userspace in a way that
1078
+
* is forwards and backwards compatible. Longer kernel structs are truncated,
1079
+
* userspace has made some kind of error if it needed the truncated information.
1080
+
* Shorter structs are zero padded.
1081
+
*/
1082
+
#define ib_respond_udata(_udata, _rep) \
1083
+
_ib_respond_udata(_udata, &(_rep), sizeof(_rep))
1084
+
1085
+
/**
1086
+
* ib_respond_empty_udata - Zero fill the response buffer to userspace
1087
+
* @_udata: The system calls ib_udata struct
1088
+
*
1089
+
* Used when there is no driver response data to return. Provides forward
1090
+
* compatability by zeroing any buffer the user may have provided.
1091
+
*/
1092
+
static inline int ib_respond_empty_udata(struct ib_udata *udata)
1093
+
{
1094
+
if (udata && udata->outlen && clear_user(udata->outbuf, udata->outlen))
1095
+
return -EFAULT;
1096
+
return 0;
1097
+
}
1077
1098
1078
1099
#endif