From 554988d6fe369719ae5b41255c577569ecf47c30 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Tue, 19 Jun 2007 09:14:26 +0200 Subject: [PATCH] [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 Signed-off-by: Jens Axboe --- drivers/cdrom/cdrom.c | 216 +++++++++++++++++++++++++++++--------------------- 1 file changed, 125 insertions(+), 91 deletions(-) diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c index 3625a05..aa5468f 100644 --- a/drivers/cdrom/cdrom.c +++ b/drivers/cdrom/cdrom.c @@ -302,7 +302,7 @@ module_param(lockdoor, bool, 0); 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 @@ int register_cdrom(struct cdrom_device_info *cdi) 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 @@ int unregister_cdrom(struct cdrom_device_info *unreg) 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 @@ int unregister_cdrom(struct cdrom_device_info *unreg) } if (cdi == NULL) { - spin_unlock(&cdrom_lock); + mutex_unlock(&cdrom_mutex); return -2; } if (prev) @@ -468,7 +468,7 @@ int unregister_cdrom(struct cdrom_device_info *unreg) else topCdromPtr = cdi->next; - spin_unlock(&cdrom_lock); + mutex_unlock(&cdrom_mutex); if (cdi->exit) cdi->exit(cdi); @@ -3289,103 +3289,137 @@ static struct cdrom_sysctl_settings { 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 -- 2.7.4