44 lines
1.7 KiB
Diff
44 lines
1.7 KiB
Diff
From 77c1ff3982c6b36961725dd19e872a1c07df7f3b Mon Sep 17 00:00:00 2001
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From: Andy Getzendanner <james.getzendanner@students.olin.edu>
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Date: Thu, 11 Feb 2010 14:04:48 +1000
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Subject: [PATCH] vgaarb: fix incorrect dereference of userspace pointer.
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This patch corrects a userspace pointer dereference in the VGA arbiter
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in 2.6.32.1.
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copy_from_user() is used at line 822 to copy the contents of buf into
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kbuf, but a call to strncmp() on line 964 uses buf rather than kbuf. This
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problem led to a GPF in strncmp() when X was started on my x86_32 systems.
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X triggered the behavior with a write of "target PCI:0000:01:00.0" to
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/dev/vga_arbiter.
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The patch has been tested against 2.6.32.1 and observed to correct the GPF
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observed when starting X or manually writing the string "target
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PCI:0000:01:00.0" to /dev/vga_arbiter.
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Signed-off-by: Andy Getzendanner <james.getzendanner@students.olin.edu>
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Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
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Cc: <stable@kernel.org>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Dave Airlie <airlied@redhat.com>
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---
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drivers/gpu/vga/vgaarb.c | 2 +-
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1 files changed, 1 insertions(+), 1 deletions(-)
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diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
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index 1ac0c93..24b56dc 100644
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--- a/drivers/gpu/vga/vgaarb.c
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+++ b/drivers/gpu/vga/vgaarb.c
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@@ -961,7 +961,7 @@ static ssize_t vga_arb_write(struct file *file, const char __user * buf,
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remaining -= 7;
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pr_devel("client 0x%p called 'target'\n", priv);
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/* if target is default */
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- if (!strncmp(buf, "default", 7))
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+ if (!strncmp(kbuf, "default", 7))
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pdev = pci_dev_get(vga_default_device());
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else {
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if (!vga_pci_str_to_vars(curr_pos, remaining,
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--
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1.6.6.1
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