compat: scsi: sg: fix v3 compat read/write interface
In the v5.4 merge window, a cleanup patch from Al Viro conflicted
with my rework of the compat handling for sg.c read(). Linus Torvalds
did a correct merge but pointed out that the resulting code is still
unsatisfactory.
I later noticed that the sg_new_read() function still gets the compat
mode wrong, when the 'count' argument is large enough to pass a
compat_sg_io_hdr object, but not a nativ sg_io_hdr.
To address both of these, move the definition of compat_sg_io_hdr
into a scsi/sg.h to make it visible to sg.c and rewrite the logic
for reading req_pack_id as well as the size check to a simpler
version that gets the expected results.
Fixes: c35a5cfb4150 ("scsi: sg: sg_read(): simplify reading ->pack_id of userland sg_io_hdr_t")
Fixes: 98aaaec4a150 ("compat_ioctl: reimplement SG_IO handling")
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index f91bcca..29c7ad0 100644
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -68,6 +68,36 @@ typedef struct sg_io_hdr
unsigned int info; /* [o] auxiliary information */
} sg_io_hdr_t; /* 64 bytes long (on i386) */
+#if defined(__KERNEL__)
+#include <linux/compat.h>
+
+struct compat_sg_io_hdr {
+ compat_int_t interface_id; /* [i] 'S' for SCSI generic (required) */
+ compat_int_t dxfer_direction; /* [i] data transfer direction */
+ unsigned char cmd_len; /* [i] SCSI command length ( <= 16 bytes) */
+ unsigned char mx_sb_len; /* [i] max length to write to sbp */
+ unsigned short iovec_count; /* [i] 0 implies no scatter gather */
+ compat_uint_t dxfer_len; /* [i] byte count of data transfer */
+ compat_uint_t dxferp; /* [i], [*io] points to data transfer memory
+ or scatter gather list */
+ compat_uptr_t cmdp; /* [i], [*i] points to command to perform */
+ compat_uptr_t sbp; /* [i], [*o] points to sense_buffer memory */
+ compat_uint_t timeout; /* [i] MAX_UINT->no timeout (unit: millisec) */
+ compat_uint_t flags; /* [i] 0 -> default, see SG_FLAG... */
+ compat_int_t pack_id; /* [i->o] unused internally (normally) */
+ compat_uptr_t usr_ptr; /* [i->o] unused internally */
+ unsigned char status; /* [o] scsi status */
+ unsigned char masked_status; /* [o] shifted, masked scsi status */
+ unsigned char msg_status; /* [o] messaging level data (optional) */
+ unsigned char sb_len_wr; /* [o] byte count actually written to sbp */
+ unsigned short host_status; /* [o] errors from host adapter */
+ unsigned short driver_status; /* [o] errors from software driver */
+ compat_int_t resid; /* [o] dxfer_len - actual_transferred */
+ compat_uint_t duration; /* [o] time taken by cmd (unit: millisec) */
+ compat_uint_t info; /* [o] auxiliary information */
+};
+#endif
+
#define SG_INTERFACE_ID_ORIG 'S'
/* Use negative values to flag difference from original sg_header structure */
