Re: [Xen-devel] [PATCH] x86/boot: Don't leak the module_map allocation in __start_xen()

["Jan Beulich" <jbeulich@xxxxxxxx>]

>>> Andrew Cooper <andrew.cooper3@xxxxxxxxxx> 04/12/19 9:17 PM >>>
>Ever since its introducion in c/s 436fb462 "x86/microcode: enable boot
>time (pre-Dom0) loading", the allocation has gone un-freed, and has its final
>use as part of constructing dom0.
>
>Xen already consideres it an error to have more than a single unaccounted-for
>module (again, logic from the same change), and will only pass the first one
>to dom0 as the initrd.
>
>Instead of having an 8 byte pointer to a bitmap which won't exceed 4 bits wide
>in any production scenario (dom0 kernel, initrd, XSM blob and microcode blob),
>allocate module_map[] on the stack and add a sanity bound for mbi->mods_count.
>
>Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

I'm a little curious how you managed to spot this pretty small, one-time leak 
...

Jan




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