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authorSasha Levin <sasha.levin@oracle.com>2012-11-15 15:51:46 -0500
committerJames Bottomley <JBottomley@Parallels.com>2012-11-30 09:08:16 +0000
commit072f19b4bea31cdd482d79f805413f2f9ac9e233 (patch)
tree39b0096f3cc90904b5f53c9fc2e9fc7c66c74e67
parenta3667aaed5698b84bad2f1b3f71adc86499f4bc6 (diff)
[SCSI] prevent stack buffer overflow in host_reset
store_host_reset() has tried to re-invent the wheel to compare sysfs strings. Unfortunately it did so poorly and never bothered to check the input from userspace before overwriting stack with it, so something simple as: echo "WoopsieWoopsie" > /sys/devices/pseudo_0/adapter0/host0/scsi_host/host0/host_reset would result in: [ 316.310101] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff81f5bac7 [ 316.310101] [ 316.320051] Pid: 6655, comm: sh Tainted: G W 3.7.0-rc5-next-20121114-sasha-00016-g5c9d68d-dirty #129 [ 316.320051] Call Trace: [ 316.340058] pps pps0: PPS event at 1352918752.620355751 [ 316.340062] pps pps0: capture assert seq #303 [ 316.320051] [<ffffffff83b3856b>] panic+0xcd/0x1f4 [ 316.320051] [<ffffffff81f5bac7>] ? store_host_reset+0xd7/0x100 [ 316.320051] [<ffffffff8110b996>] __stack_chk_fail+0x16/0x20 [ 316.320051] [<ffffffff81f5bac7>] store_host_reset+0xd7/0x100 [ 316.320051] [<ffffffff81e55bb3>] dev_attr_store+0x13/0x30 [ 316.320051] [<ffffffff812f7db1>] sysfs_write_file+0x101/0x170 [ 316.320051] [<ffffffff8127acc8>] vfs_write+0xb8/0x180 [ 316.320051] [<ffffffff8127ae80>] sys_write+0x50/0xa0 [ 316.320051] [<ffffffff83c03418>] tracesys+0xe1/0xe6 Fix this by uninventing whatever was going on there and just use sysfs_streq. Bug introduced by 29443691 ("[SCSI] scsi: Added support for adapter and firmware reset"). [jejb: added necessary const to prevent compile warnings] Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: <stable@vger.kernel.org> #3.2+ Signed-off-by: James Bottomley <JBottomley@Parallels.com>
-rw-r--r--drivers/scsi/scsi_sysfs.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index ce5224c92eda..931a7d954203 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -247,11 +247,11 @@ show_shost_active_mode(struct device *dev,
static DEVICE_ATTR(active_mode, S_IRUGO | S_IWUSR, show_shost_active_mode, NULL);
-static int check_reset_type(char *str)
+static int check_reset_type(const char *str)
{
- if (strncmp(str, "adapter", 10) == 0)
+ if (sysfs_streq(str, "adapter"))
return SCSI_ADAPTER_RESET;
- else if (strncmp(str, "firmware", 10) == 0)
+ else if (sysfs_streq(str, "firmware"))
return SCSI_FIRMWARE_RESET;
else
return 0;
@@ -264,12 +264,9 @@ store_host_reset(struct device *dev, struct device_attribute *attr,
struct Scsi_Host *shost = class_to_shost(dev);
struct scsi_host_template *sht = shost->hostt;
int ret = -EINVAL;
- char str[10];
int type;
- sscanf(buf, "%s", str);
- type = check_reset_type(str);
-
+ type = check_reset_type(buf);
if (!type)
goto exit_store_host_reset;