[PATCH] cdrom_sysctl_info fix
Fix the cdrom_sysctl_info possible buffer overwrite bug. Also
fix the locking of accessing topCdromPtr pointer.
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 3625a05..aa5468f4 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -302,7 +302,7 @@
module_param(check_media_type, bool, 0);
module_param(mrw_format_restart, bool, 0);
-static DEFINE_SPINLOCK(cdrom_lock);
+static DEFINE_MUTEX(cdrom_mutex);
static const char *mrw_format_status[] = {
"not mrw",
@@ -438,10 +438,10 @@
cdo->generic_packet = cdrom_dummy_generic_packet;
cdinfo(CD_REG_UNREG, "drive \"/dev/%s\" registered\n", cdi->name);
- spin_lock(&cdrom_lock);
+ mutex_lock(&cdrom_mutex);
cdi->next = topCdromPtr;
topCdromPtr = cdi;
- spin_unlock(&cdrom_lock);
+ mutex_unlock(&cdrom_mutex);
return 0;
}
#undef ENSURE
@@ -452,7 +452,7 @@
cdinfo(CD_OPEN, "entering unregister_cdrom\n");
prev = NULL;
- spin_lock(&cdrom_lock);
+ mutex_lock(&cdrom_mutex);
cdi = topCdromPtr;
while (cdi && cdi != unreg) {
prev = cdi;
@@ -460,7 +460,7 @@
}
if (cdi == NULL) {
- spin_unlock(&cdrom_lock);
+ mutex_unlock(&cdrom_mutex);
return -2;
}
if (prev)
@@ -468,7 +468,7 @@
else
topCdromPtr = cdi->next;
- spin_unlock(&cdrom_lock);
+ mutex_unlock(&cdrom_mutex);
if (cdi->exit)
cdi->exit(cdi);
@@ -3289,103 +3289,137 @@
int check; /* check media type */
} cdrom_sysctl_settings;
+enum cdrom_print_option {
+ CTL_NAME,
+ CTL_SPEED,
+ CTL_SLOTS,
+ CTL_CAPABILITY
+};
+
+static int cdrom_print_info(const char *header, int val, char *info,
+ int *pos, enum cdrom_print_option option)
+{
+ const int max_size = sizeof(cdrom_sysctl_settings.info);
+ struct cdrom_device_info *cdi;
+ int ret;
+
+ ret = scnprintf(info + *pos, max_size - *pos, header);
+ if (!ret)
+ return 1;
+
+ *pos += ret;
+
+ for (cdi = topCdromPtr; cdi; cdi = cdi->next) {
+ switch (option) {
+ case CTL_NAME:
+ ret = scnprintf(info + *pos, max_size - *pos,
+ "\t%s", cdi->name);
+ break;
+ case CTL_SPEED:
+ ret = scnprintf(info + *pos, max_size - *pos,
+ "\t%d", cdi->speed);
+ break;
+ case CTL_SLOTS:
+ ret = scnprintf(info + *pos, max_size - *pos,
+ "\t%d", cdi->capacity);
+ break;
+ case CTL_CAPABILITY:
+ ret = scnprintf(info + *pos, max_size - *pos,
+ "\t%d", CDROM_CAN(val) != 0);
+ break;
+ default:
+ printk(KERN_INFO "cdrom: invalid option%d\n", option);
+ return 1;
+ }
+ if (!ret)
+ return 1;
+ *pos += ret;
+ }
+
+ return 0;
+}
+
static int cdrom_sysctl_info(ctl_table *ctl, int write, struct file * filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
- int pos;
- struct cdrom_device_info *cdi;
+ int pos;
char *info = cdrom_sysctl_settings.info;
+ const int max_size = sizeof(cdrom_sysctl_settings.info);
if (!*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
+ mutex_lock(&cdrom_mutex);
+
pos = sprintf(info, "CD-ROM information, " VERSION "\n");
- pos += sprintf(info+pos, "\ndrive name:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%s", cdi->name);
-
- pos += sprintf(info+pos, "\ndrive speed:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", cdi->speed);
-
- pos += sprintf(info+pos, "\ndrive # of slots:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", cdi->capacity);
-
- pos += sprintf(info+pos, "\nCan close tray:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_CLOSE_TRAY) != 0);
-
- pos += sprintf(info+pos, "\nCan open tray:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_OPEN_TRAY) != 0);
-
- pos += sprintf(info+pos, "\nCan lock tray:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_LOCK) != 0);
-
- pos += sprintf(info+pos, "\nCan change speed:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_SELECT_SPEED) != 0);
-
- pos += sprintf(info+pos, "\nCan select disk:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_SELECT_DISC) != 0);
-
- pos += sprintf(info+pos, "\nCan read multisession:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_MULTI_SESSION) != 0);
-
- pos += sprintf(info+pos, "\nCan read MCN:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_MCN) != 0);
-
- pos += sprintf(info+pos, "\nReports media changed:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_MEDIA_CHANGED) != 0);
-
- pos += sprintf(info+pos, "\nCan play audio:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_PLAY_AUDIO) != 0);
-
- pos += sprintf(info+pos, "\nCan write CD-R:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_CD_R) != 0);
-
- pos += sprintf(info+pos, "\nCan write CD-RW:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_CD_RW) != 0);
-
- pos += sprintf(info+pos, "\nCan read DVD:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_DVD) != 0);
-
- pos += sprintf(info+pos, "\nCan write DVD-R:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_DVD_R) != 0);
-
- pos += sprintf(info+pos, "\nCan write DVD-RAM:");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_DVD_RAM) != 0);
-
- pos += sprintf(info+pos, "\nCan read MRW:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_MRW) != 0);
-
- pos += sprintf(info+pos, "\nCan write MRW:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_MRW_W) != 0);
-
- pos += sprintf(info+pos, "\nCan write RAM:\t");
- for (cdi=topCdromPtr;cdi!=NULL;cdi=cdi->next)
- pos += sprintf(info+pos, "\t%d", CDROM_CAN(CDC_RAM) != 0);
-
- strcpy(info+pos,"\n\n");
-
- return proc_dostring(ctl, write, filp, buffer, lenp, ppos);
+ if (cdrom_print_info("\ndrive name:\t", 0, info, &pos, CTL_NAME))
+ goto done;
+ if (cdrom_print_info("\ndrive speed:\t", 0, info, &pos, CTL_SPEED))
+ goto done;
+ if (cdrom_print_info("\ndrive # of slots:", 0, info, &pos, CTL_SLOTS))
+ goto done;
+ if (cdrom_print_info("\nCan close tray:\t",
+ CDC_CLOSE_TRAY, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan open tray:\t",
+ CDC_OPEN_TRAY, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan lock tray:\t",
+ CDC_LOCK, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan change speed:",
+ CDC_SELECT_SPEED, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan select disk:",
+ CDC_SELECT_DISC, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan read multisession:",
+ CDC_MULTI_SESSION, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan read MCN:\t",
+ CDC_MCN, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nReports media changed:",
+ CDC_MEDIA_CHANGED, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan play audio:\t",
+ CDC_PLAY_AUDIO, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan write CD-R:\t",
+ CDC_CD_R, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan write CD-RW:",
+ CDC_CD_RW, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan read DVD:\t",
+ CDC_DVD, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan write DVD-R:",
+ CDC_DVD_R, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan write DVD-RAM:",
+ CDC_DVD_RAM, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan read MRW:\t",
+ CDC_MRW, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan write MRW:\t",
+ CDC_MRW_W, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (cdrom_print_info("\nCan write RAM:\t",
+ CDC_RAM, info, &pos, CTL_CAPABILITY))
+ goto done;
+ if (!scnprintf(info + pos, max_size - pos, "\n\n"))
+ goto done;
+doit:
+ mutex_unlock(&cdrom_mutex);
+ return proc_dostring(ctl, write, filp, buffer, lenp, ppos);
+done:
+ printk(KERN_INFO "cdrom: info buffer too small\n");
+ goto doit;
}
/* Unfortunately, per device settings are not implemented through
