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").
Signed-off-by: Sasha Levin <[email protected]>
---
drivers/scsi/scsi_sysfs.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index ce5224c..77ba946 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -249,9 +249,9 @@ static DEVICE_ATTR(active_mode, S_IRUGO | S_IWUSR, show_shost_active_mode, NULL)
static int check_reset_type(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;
--
1.8.0
Am Donnerstag 15 November 2012, 15:51:46 schrieb Sasha Levin:
> 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").
>
> Signed-off-by: Sasha Levin <[email protected]>
That revision is in 3.2 and all following, so I think this needs to go into
stable, too.
Eike
On Thu, 2012-11-15 at 15:51 -0500, Sasha Levin wrote:
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index ce5224c..77ba946 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -249,9 +249,9 @@ static DEVICE_ATTR(active_mode, S_IRUGO | S_IWUSR, show_shost_active_mode, NULL)
>
> static int check_reset_type(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;
You didn't compile test this:
CC [M] drivers/scsi/scsi_sysfs.o
drivers/scsi/scsi_sysfs.c: In function ‘store_host_reset’:
drivers/scsi/scsi_sysfs.c:269:2: warning: passing argument 1 of ‘check_reset_type’ discards ‘const’ qualifier from pointer target type [enabled by default]
drivers/scsi/scsi_sysfs.c:250:12: note: expected ‘char *’ but argument is of type ‘const char *’
It needs a const in check_reset_type().
I've added it.
James