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16660db3fc
Fix the following out-of-bounds warnings by embedding existing struct
htb_rel_query into struct mpt3_addnl_diag_query, instead of duplicating its
members:
include/linux/fortify-string.h:20:29: warning: '__builtin_memcpy' offset [19, 32] from the object at 'karg' is out of the bounds of referenced subobject 'buffer_rel_condition' with type 'short unsigned int' at offset 16 [-Warray-bounds]
include/linux/fortify-string.h:22:29: warning: '__builtin_memset' offset [19, 32] from the object at 'karg' is out of the bounds of referenced subobject 'buffer_rel_condition' with type 'short unsigned int' at offset 16 [-Warray-bounds]
The problem is that the original code is trying to copy data into a bunch
of struct members adjacent to each other in a single call to memcpy(). All
those members are exactly the same contained in struct htb_rel_query, so
instead of duplicating them into struct mpt3_addnl_diag_query, replace them
with new member rel_query of type struct htb_rel_query. So, now that this
new object is introduced, memcpy() doesn't overrun the length of
&karg.buffer_rel_condition, because the address of the new struct object
_rel_query_ is used as destination, instead. The same issue is present when
calling memset(), and it is fixed with this same approach.
Below is a comparison of struct mpt3_addnl_diag_query, before and after
this change (the size and cachelines remain the same):
$ pahole -C mpt3_addnl_diag_query drivers/scsi/mpt3sas/mpt3sas_ctl.o
struct mpt3_addnl_diag_query {
struct mpt3_ioctl_header hdr; /* 0 12 */
uint32_t unique_id; /* 12 4 */
uint16_t buffer_rel_condition; /* 16 2 */
uint16_t reserved1; /* 18 2 */
uint32_t trigger_type; /* 20 4 */
uint32_t trigger_info_dwords[2]; /* 24 8 */
uint32_t reserved2[2]; /* 32 8 */
/* size: 40, cachelines: 1, members: 7 */
/* last cacheline: 40 bytes */
};
$ pahole -C mpt3_addnl_diag_query drivers/scsi/mpt3sas/mpt3sas_ctl.o
struct mpt3_addnl_diag_query {
struct mpt3_ioctl_header hdr; /* 0 12 */
uint32_t unique_id; /* 12 4 */
struct htb_rel_query rel_query; /* 16 16 */
uint32_t reserved2[2]; /* 32 8 */
/* size: 40, cachelines: 1, members: 4 */
/* last cacheline: 40 bytes */
};
Also, this helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines on
memcpy().
Link: https://github.com/KSPP/linux/issues/109
Link: https://lore.kernel.org/lkml/60659889.bJJILx2THu3hlpxW%25lkp@intel.com/
Link: https://lore.kernel.org/r/20210401162054.GA397186@embeddedor
Build-tested-by: kernel test robot <lkp@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.