49 lines
1.5 KiB
Diff
49 lines
1.5 KiB
Diff
From: Al Viro <viro@zeniv.linux.org.uk>
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Date: Fri, 16 Dec 2016 13:42:06 -0500
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Subject: sg_write()/bsg_write() is not fit to be called under KERNEL_DS
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Origin: https://git.kernel.org/linus/128394eff343fc6d2f32172f03e24829539c5835
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Both damn things interpret userland pointers embedded into the payload;
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worse, they are actually traversing those. Leaving aside the bad
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API design, this is very much _not_ safe to call with KERNEL_DS.
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Bail out early if that happens.
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Cc: stable@vger.kernel.org
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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---
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block/bsg.c | 3 +++
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drivers/scsi/sg.c | 3 +++
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2 files changed, 6 insertions(+)
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diff --git a/block/bsg.c b/block/bsg.c
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index 8a05a404ae70..a57046de2f07 100644
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--- a/block/bsg.c
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+++ b/block/bsg.c
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@@ -655,6 +655,9 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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dprintk("%s: write %Zd bytes\n", bd->name, count);
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+ if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
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+ return -EINVAL;
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+
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bsg_set_block(bd, file);
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bytes_written = 0;
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diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
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index 070332eb41f3..dbe5b4b95df0 100644
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--- a/drivers/scsi/sg.c
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+++ b/drivers/scsi/sg.c
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@@ -581,6 +581,9 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
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sg_io_hdr_t *hp;
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unsigned char cmnd[SG_MAX_CDB_SIZE];
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+ if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
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+ return -EINVAL;
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+
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if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
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return -ENXIO;
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SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
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--
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2.11.0
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