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| author | Sasha Levin <sasha.levin@oracle.com> | 2012-11-15 15:51:46 -0500 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-11-30 09:08:16 +0000 |
| commit | 072f19b4bea31cdd482d79f805413f2f9ac9e233 (patch) | |
| tree | 39b0096f3cc90904b5f53c9fc2e9fc7c66c74e67 | |
| parent | a3667aaed5698b84bad2f1b3f71adc86499f4bc6 (diff) | |
| download | linux-072f19b4bea31cdd482d79f805413f2f9ac9e233.tar.gz linux-072f19b4bea31cdd482d79f805413f2f9ac9e233.tar.bz2 linux-072f19b4bea31cdd482d79f805413f2f9ac9e233.zip | |
[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.c | 11 |
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; |