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") Signed-off-by: Arnd Bergmann arnd@arndb.de --- block/scsi_ioctl.c | 29 +---------- drivers/scsi/sg.c | 126 +++++++++++++++++++++------------------------ include/scsi/sg.h | 30 +++++++++++ 3 files changed, 90 insertions(+), 95 deletions(-)
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c index 650bade5ea5a..b61dbf4d8443 100644 --- a/block/scsi_ioctl.c +++ b/block/scsi_ioctl.c @@ -20,6 +20,7 @@ #include <scsi/scsi.h> #include <scsi/scsi_ioctl.h> #include <scsi/scsi_cmnd.h> +#include <scsi/sg.h>
struct blk_cmd_filter { unsigned long read_ok[BLK_SCSI_CMD_PER_LONG]; @@ -550,34 +551,6 @@ static inline int blk_send_start_stop(struct request_queue *q, return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data); }
-#ifdef CONFIG_COMPAT -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 - int put_sg_io_hdr(const struct sg_io_hdr *hdr, void __user *argp) { #ifdef CONFIG_COMPAT diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 160748ad9c0f..eace8886d95a 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -405,6 +405,38 @@ sg_release(struct inode *inode, struct file *filp) return 0; }
+static int get_sg_io_pack_id(int *pack_id, void __user *buf, size_t count) +{ + struct sg_header __user *old_hdr = buf; + int reply_len; + + if (count >= SZ_SG_HEADER) { + /* negative reply_len means v3 format, otherwise v1/v2 */ + if (get_user(reply_len, &old_hdr->reply_len)) + return -EFAULT; + + if (reply_len >= 0) + return get_user(*pack_id, &old_hdr->pack_id); + + if (in_compat_syscall() && + count >= sizeof(struct compat_sg_io_hdr)) { + struct compat_sg_io_hdr __user *hp = buf; + + return get_user(*pack_id, &hp->pack_id); + } + + if (count >= sizeof(struct sg_io_hdr)) { + struct sg_io_hdr __user *hp = buf; + + return get_user(*pack_id, &hp->pack_id); + } + } + + /* no valid header was passed, so ignore the pack_id */ + *pack_id = -1; + return 0; +} + static ssize_t sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos) { @@ -413,8 +445,8 @@ sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos) Sg_request *srp; int req_pack_id = -1; sg_io_hdr_t *hp; - struct sg_header *old_hdr = NULL; - int retval = 0; + struct sg_header *old_hdr; + int retval;
/* * This could cause a response to be stranded. Close the associated @@ -429,79 +461,34 @@ sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos) SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_read: count=%d\n", (int) count));
- if (sfp->force_packid && (count >= SZ_SG_HEADER)) { - old_hdr = memdup_user(buf, SZ_SG_HEADER); - if (IS_ERR(old_hdr)) - return PTR_ERR(old_hdr); - if (old_hdr->reply_len < 0) { - if (count >= SZ_SG_IO_HDR) { - /* - * This is stupid. - * - * We're copying the whole sg_io_hdr_t from user - * space just to get the 'pack_id' field. But the - * field is at different offsets for the compat - * case, so we'll use "get_sg_io_hdr()" to copy - * the whole thing and convert it. - * - * We could do something like just calculating the - * offset based of 'in_compat_syscall()', but the - * 'compat_sg_io_hdr' definition is in the wrong - * place for that. - */ - sg_io_hdr_t *new_hdr; - new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL); - if (!new_hdr) { - retval = -ENOMEM; - goto free_old_hdr; - } - retval = get_sg_io_hdr(new_hdr, buf); - req_pack_id = new_hdr->pack_id; - kfree(new_hdr); - if (retval) { - retval = -EFAULT; - goto free_old_hdr; - } - } - } else - req_pack_id = old_hdr->pack_id; - } + if (sfp->force_packid) + retval = get_sg_io_pack_id(&req_pack_id, buf, count); + if (retval) + return retval; + srp = sg_get_rq_mark(sfp, req_pack_id); if (!srp) { /* now wait on packet to arrive */ - if (atomic_read(&sdp->detaching)) { - retval = -ENODEV; - goto free_old_hdr; - } - if (filp->f_flags & O_NONBLOCK) { - retval = -EAGAIN; - goto free_old_hdr; - } + if (atomic_read(&sdp->detaching)) + return -ENODEV; + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; retval = wait_event_interruptible(sfp->read_wait, (atomic_read(&sdp->detaching) || (srp = sg_get_rq_mark(sfp, req_pack_id)))); - if (atomic_read(&sdp->detaching)) { - retval = -ENODEV; - goto free_old_hdr; - } - if (retval) { + if (atomic_read(&sdp->detaching)) + return -ENODEV; + if (retval) /* -ERESTARTSYS as signal hit process */ - goto free_old_hdr; - } - } - if (srp->header.interface_id != '\0') { - retval = sg_new_read(sfp, buf, count, srp); - goto free_old_hdr; + return retval; } + if (srp->header.interface_id != '\0') + return sg_new_read(sfp, buf, count, srp);
hp = &srp->header; - if (old_hdr == NULL) { - old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL); - if (! old_hdr) { - retval = -ENOMEM; - goto free_old_hdr; - } - } - memset(old_hdr, 0, SZ_SG_HEADER); + old_hdr = kzalloc(SZ_SG_HEADER, GFP_KERNEL); + if (!old_hdr) + return -ENOMEM; + old_hdr->reply_len = (int) hp->timeout; old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */ old_hdr->pack_id = hp->pack_id; @@ -575,7 +562,12 @@ sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp) int err = 0, err2; int len;
- if (count < SZ_SG_IO_HDR) { + if (in_compat_syscall()) { + if (count < sizeof(struct compat_sg_io_hdr)) { + err = -EINVAL; + goto err_out; + } + } else if (count < SZ_SG_IO_HDR) { err = -EINVAL; goto err_out; } diff --git a/include/scsi/sg.h b/include/scsi/sg.h index f91bcca604e4..29c7ad04d2e2 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 */