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cxlflash: Fix AFU version access/storage and add check 

The AFU version is stored as a non-terminated string of bytes within
a 64-bit little-endian register. Presently the value is read directly
(no MMIO accessor) and is stored in a buffer that is not big enough
to contain a NULL terminator. Additionally the version obtained is not
evaluated against a known value to prevent usage with unsupported AFUs.
All of these deficiencies can lead to a variety of problems.

To remedy, use the correct MMIO accessor to read the version value into
a null-terminated buffer and add a check to prevent an incompatible AFU
from being used with this driver.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This commit is contained in:
Matthew R. Ochs 2015-10-21 15:14:01 -05:00 committed by James Bottomley
parent 964497b3bf
commit e5ce067b7b
3 changed files with 14 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/scsi/cxlflash/common.h
View File

@ -179,7 +179,7 @@ struct afu {
u32 cmd_couts; /* Number of command checkouts */
u32 internal_lun; /* User-desired LUN mode for this AFU */
char version[8];
char version[16];
u64 interface_version;
struct cxlflash_cfg *parent; /* Pointer back to parent cxlflash_cfg */

18
drivers/scsi/cxlflash/main.c
View File

@ -1751,14 +1751,20 @@ static int init_afu(struct cxlflash_cfg *cfg)
goto err1;
}
/* don't byte reverse on reading afu_version, else the string form */
/* will be backwards */
reg = afu->afu_map->global.regs.afu_version;
memcpy(afu->version, &reg, 8);
/* No byte reverse on reading afu_version or string will be backwards */
reg = readq(&afu->afu_map->global.regs.afu_version);
memcpy(afu->version, &reg, sizeof(reg));
afu->interface_version =
readq_be(&afu->afu_map->global.regs.interface_version);
pr_debug("%s: afu version %s, interface version 0x%llX\n",
__func__, afu->version, afu->interface_version);
if ((afu->interface_version + 1) == 0) {
pr_err("Back level AFU, please upgrade. AFU version %s "
"interface version 0x%llx\n", afu->version,
afu->interface_version);
rc = -EINVAL;
goto err1;
} else
pr_debug("%s: afu version %s, interface version 0x%llX\n",
__func__, afu->version, afu->interface_version);
rc = start_afu(cfg);
if (rc) {

2
drivers/scsi/cxlflash/sislite.h
View File

@ -340,7 +340,7 @@ struct sisl_global_regs {
#define SISL_AFUCONF_MBOX_CLR_READ 0x0010ULL
__be64 afu_config;
__be64 rsvd[0xf8];
__be64 afu_version;
__le64 afu_version;
__be64 interface_version;
};