[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] xen/xsm: forbid PV guest console reads
On 09/30/2013 12:10 PM, Jan Beulich wrote: On 30.09.13 at 17:48, Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> wrote:When the hypervisor was compiled in debug mode (with VERBOSE defined), PV guests incorrectly had access to both read and write to the console. Change this to only allow write access; since such writes were limited by log levels in 48d50de8e0, remove the dependency on VERBOSE completely.I disagree, and iirc I disagreed already when you tried to drop the dependency on VERBOSE with that earlier patch.Reported-by: Jan Beulich <JBeulich@xxxxxxxx> Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> --- Alternatively, if controlling writes with VERBOSE is still desired, the ifdef VERBOSE can be retained surrounding the if() with the following commit message:That's what I'd want to see go in. Jan This patch retains the existing behavior where only HVM guests can use the console for output, and only via the 0xE9 I/O port. With Konrad's Linux patch, this means that xen_raw_console_write in non-dom0 will produce output only on Xen <= 4.3 (which returns -ENOSYS rather than -EPERM, as this code does). ------------------------8<---------------------------------------------- The CONSOLEIO_read operation was incorrectly allowed to PV guests if the hypervisor was compiled in debug mode (with VERBOSE defined). Reported-by: Jan Beulich <JBeulich@xxxxxxxx> Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> --- xen/include/xsm/dummy.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h index 2abf018..b1edd29 100644 --- a/xen/include/xsm/dummy.h +++ b/xen/include/xsm/dummy.h @@ -233,10 +233,10 @@ static XSM_INLINE int xsm_console_io(XSM_DEFAULT_ARG struct domain *d, int cmd) { XSM_ASSERT_ACTION(XSM_OTHER); #ifdef VERBOSE - return xsm_default_action(XSM_HOOK, current->domain, NULL); -#else - return xsm_default_action(XSM_PRIV, current->domain, NULL); + if ( cmd == CONSOLEIO_write ) + return xsm_default_action(XSM_HOOK, d, NULL); #endif + return xsm_default_action(XSM_PRIV, d, NULL); }static XSM_INLINE int xsm_profile(XSM_DEFAULT_ARG struct domain *d, int op) _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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