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authorAl Viro <viro@zeniv.linux.org.uk>2016-12-16 13:42:06 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-09 08:32:25 +0100
commit3f3a6bbe6f9f5e895d8945494173594ee51632da (patch)
tree07d69582b4b05fe1b7cf99dc58ab907eb4d0113a /block
parentd024532a97db32db4b0fc4cd27c7a9ac15b84e5b (diff)
sg_write()/bsg_write() is not fit to be called under KERNEL_DS
commit 128394eff343fc6d2f32172f03e24829539c5835 upstream. Both damn things interpret userland pointers embedded into the payload; worse, they are actually traversing those. Leaving aside the bad API design, this is very much _not_ safe to call with KERNEL_DS. Bail out early if that happens. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/bsg.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/block/bsg.c b/block/bsg.c
index d214e929ce18..b9a53615bdef 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -655,6 +655,9 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
dprintk("%s: write %Zd bytes\n", bd->name, count);
+ if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
+ return -EINVAL;
+
bsg_set_block(bd, file);
bytes_written = 0;