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* [Qemu-devel] [PATCH] pc: check for underflow in load_linux
@ 2015-09-14 10:07 Paolo Bonzini
  2015-09-16 11:02 ` Michael Tokarev
  0 siblings, 1 reply; 2+ messages in thread
From: Paolo Bonzini @ 2015-09-14 10:07 UTC (permalink / raw)
  To: qemu-devel; +Cc: qemu-trivial

If (setup_size+1)*512 is small enough, kernel_size -= setup_size can allocate
a huge amount of memory.  Avoid that.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/i386/pc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 56aecce..6a312bd 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -986,6 +986,10 @@ static void load_linux(PCMachineState *pcms,
         setup_size = 4;
     }
     setup_size = (setup_size+1)*512;
+    if (setup_size > kernel_size) {
+        fprintf(stderr, "qemu: invalid kernel header\n");
+        exit(1);
+    }
     kernel_size -= setup_size;
 
     setup  = g_malloc(setup_size);
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [Qemu-devel] [PATCH] pc: check for underflow in load_linux
  2015-09-14 10:07 [Qemu-devel] [PATCH] pc: check for underflow in load_linux Paolo Bonzini
@ 2015-09-16 11:02 ` Michael Tokarev
  0 siblings, 0 replies; 2+ messages in thread
From: Michael Tokarev @ 2015-09-16 11:02 UTC (permalink / raw)
  To: Paolo Bonzini, qemu-devel; +Cc: qemu-trivial

14.09.2015 13:07, Paolo Bonzini wrote:
> If (setup_size+1)*512 is small enough, kernel_size -= setup_size can allocate
> a huge amount of memory.  Avoid that.

Applied to -trivial, thanks!

/mjt

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2015-09-16 11:02 UTC | newest]

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