[Qemu-stable] [PATCH 020/108] tsc210x: fix buffer overrun on invalid state load

[Michael Roth]

From: "Michael S. Tsirkin" <address@hidden>

CVE-2013-4539

s->precision, nextprecision, function and nextfunction
come from wire and are used
as idx into resolution[] in TSC_CUT_RESOLUTION.

Validate after load to avoid buffer overrun.

Cc: Andreas Färber <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
(cherry picked from commit 5193be3be35f29a35bc465036cd64ad60d43385f)
Signed-off-by: Michael Roth <address@hidden>
---
 hw/input/tsc210x.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/input/tsc210x.c b/hw/input/tsc210x.c
index 485c9e5..aa5b688 100644
--- a/hw/input/tsc210x.c
+++ b/hw/input/tsc210x.c
@@ -1070,9 +1070,21 @@ static int tsc210x_load(QEMUFile *f, void *opaque, int 
version_id)
     s->enabled = qemu_get_byte(f);
     s->host_mode = qemu_get_byte(f);
     s->function = qemu_get_byte(f);
+    if (s->function < 0 || s->function >= ARRAY_SIZE(mode_regs)) {
+        return -EINVAL;
+    }
     s->nextfunction = qemu_get_byte(f);
+    if (s->nextfunction < 0 || s->nextfunction >= ARRAY_SIZE(mode_regs)) {
+        return -EINVAL;
+    }
     s->precision = qemu_get_byte(f);
+    if (s->precision < 0 || s->precision >= ARRAY_SIZE(resolution)) {
+        return -EINVAL;
+    }
     s->nextprecision = qemu_get_byte(f);
+    if (s->nextprecision < 0 || s->nextprecision >= ARRAY_SIZE(resolution)) {
+        return -EINVAL;
+    }
     s->filter = qemu_get_byte(f);
     s->pin_func = qemu_get_byte(f);
     s->ref = qemu_get_byte(f);
-- 
1.9.1