I don't think this will work. I see two problems: (1) You can't filter TEST_UNIT_READY (opcode 0). Not a big deal, but a theoretical problem.
(2) We need to be able to filter at the originator. For example, MODE_SENSE is perfectly fine to send to a CD-ROM, but not to a hard-disk. We can't make that distinction with your code, unless we put the filtering code not in queuecommand but in places like sd.c.... or we need to change the filter to also take a device type. Matt On Sat, Apr 05, 2003 at 09:30:41AM -0600, James Bottomley wrote: > On Mon, 2003-03-24 at 11:30, Matthew Dharm wrote: > > On Mon, Mar 24, 2003 at 09:15:57AM -0600, James Bottomley wrote: > > > OK, I can do this: A simple one with either a blacklist (reject these > > > commands) or whitelist (only accept these commands) going by the first > > > command byte OK? > > > > Well, you need to go by more than the first command byte -- ex. INQUIRY is > > okay, unless length != 36 or EVPD. > > > > I think a blacklist is probably in order, but with a BIG COMMENT mentioning > > that if someone adds new commands into the code paths they should at least > > consider if they belong in the blacklist. > > OK, try the attached. There is no central blacklist, you must construct > it on a per driver basis, so in the queuecommand of your driver you have > a: > > static struct scsi_cmd_filter filter = > { SCSI_FILTER_BLACKLIST , > { MODE_SENSE, SCSI_FILTER_INQUIRY_NOT36, 0 } }; > > if(scsi_filter_cmd(SCp, &filter)) { > SCp->scsi_done(SCp); > return 0; > } > > to use the filter (I think, I've compiled but not tested it). > > Let me know how it goes. > > James > > ===== drivers/scsi/scsi.h 1.68 vs edited ===== > --- 1.68/drivers/scsi/scsi.h Mon Mar 24 11:23:37 2003 > +++ edited/drivers/scsi/scsi.h Sat Apr 5 09:24:38 2003 > @@ -959,4 +959,39 @@ > extern int scsi_sysfs_register(void); > extern void scsi_sysfs_unregister(void); > > +struct scsi_cmd_filter { > + enum { > + SCSI_FILTER_WHITELIST, > + SCSI_FILTER_BLACKLIST > + } type; > + /* normal scsi commands are bytes, exceptions are words. The format > + * of the exceptions is: > + * > + * Byte 15: invert the specific condition > + * Byte 14-12: Reserved > + * Byte 11-8: command opcode (must be > 0) > + * Byte 7-0: Command specific */ > + unsigned short commands[]; > +}; > + > +extern int scsi_filter_cmd(struct scsi_cmnd *, struct scsi_cmd_filter *); > + > +/* exception definitions for the filter */ > +#define SCSI_FILTER_INVERT 0x8000 > + > +/* opcodes for the filter */ > +#define SCSI_FILTER_INQUIRY 0x0100 > + > +/* useful filter commands */ > +#define SCSI_FILTER_INQUIRY_36 (SCSI_FILTER_INQUIRY | 36) > +#define SCSI_FILTER_INQUIRY_NOT36 (SCSI_FILTER_INVERT | SCSI_FILTER_INQUIRY | 36) > + > +static inline unsigned short scsi_filter_opcode(unsigned short command) { > + return command & 0x7f00; > +} > + > +static inline unsigned char scsi_filter_data(unsigned short command) { > + return (unsigned char)(command & 0x00ff); > +} > + > #endif /* _SCSI_H */ > ===== drivers/scsi/scsi_lib.c 1.75 vs edited ===== > --- 1.75/drivers/scsi/scsi_lib.c Fri Mar 14 18:35:27 2003 > +++ edited/drivers/scsi/scsi_lib.c Sat Apr 5 09:27:35 2003 > @@ -1375,3 +1375,71 @@ > kmem_cache_destroy(sgp->slab); > } > } > + > +static inline int scsi_filter_exceptions(struct scsi_cmnd *cmd, > + unsigned short command) > +{ > + int found = 0; > + > + /* specials begin at 0x100 */ > + if(command < 0x100) > + return 0; > + > + switch(scsi_filter_opcode(command)) { > + > + case SCSI_FILTER_INQUIRY: > + if(cmd->cmnd[0] != INQUIRY) > + return 0; > + /* does the transfer length match the data */ > + found = (cmd->cmnd[4] == scsi_filter_data(command)); > + /* now check for inversion */ > + if(command & SCSI_FILTER_INVERT) > + found = !found; > + return found; > + default: > + /* unrecognized filter */ > + return 0; > + } > +} > + > +/** > + * scsi_filter_cmd - Filter a given command against a list > + * @cmd: command to be filtered. > + * @filter: pointer to the filter containing the type (black/white list) and > + * zero terminated list of commands to filter against (first byte only). > + * > + * Returns 0 if the filter passed successfully and the driver can continue > + * processing the command or 1 if the filter failed and the command should > + * be finished (via ->scsi_done). In the latter case, the command will have > + * the sense fields filled in indicating the correct sense for an illegal > + * request. > + **/ > +int scsi_filter_cmd(struct scsi_cmnd *cmd, struct scsi_cmd_filter *filter) > +{ > + int found = 0; > + unsigned short *command; > + > + for(command = filter->commands; *command; command++) { > + found = scsi_filter_exceptions(cmd, *command); > + found += (cmd->cmnd[0] != *command); > + if(found) > + break; > + } > + > + if((found && filter->type == SCSI_FILTER_WHITELIST) || > + (!found && filter->type == SCSI_FILTER_BLACKLIST)) > + return 0; > + > + /* fill in the Check Condition/Illegal request */ > + cmd->result = SAM_STAT_CHECK_CONDITION; > + memset(cmd->sense_buffer, '\0', sizeof(cmd->sense_buffer)); > + cmd->sense_buffer[0] = 0xF0; /* valid, response code 0x70 */ > + cmd->sense_buffer[2] = ILLEGAL_REQUEST; > + > + /* ASC 0x20, ASCQ 0x00: Invalid command operation code */ > + cmd->sense_buffer[12] = 0x20; > + cmd->sense_buffer[13] = 0x00; > + > + return 1; > +} > + -- Matthew Dharm Home: [EMAIL PROTECTED] Maintainer, Linux USB Mass Storage Driver IT KEEPS ASKING ME WHERE I WANT TO GO TODAY! I DONT WANT TO GO ANYWHERE! -- Greg User Friendly, 11/28/97
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