Vinson Lee <[email protected]> wrote: > On Thu, Nov 6, 2014 at 2:36 PM, Kamal Mostafa <[email protected]> wrote: >> 3.13.11.11 -stable review patch. If anyone has any objections, please let >> me know. >> >> ------------------ >> >> From: Nadav Amit <[email protected]> >> >> commit 7e46dddd6f6cd5dbf3c7bd04a7e75d19475ac9f2 upstream. >> >> Commit d1442d85cc30 ("KVM: x86: Handle errors when RIP is set during far >> jumps") introduced a bug that caused the fix to be incomplete. Due to >> incorrect evaluation, far jump to segment with L bit cleared (i.e., 32-bit >> segment) and RIP with any of the high bits set (i.e, RIP[63:32] != 0) set may >> not trigger #GP. As we know, this imposes a security problem. >> >> In addition, the condition for two warnings was incorrect. >> >> Fixes: d1442d85cc30ea75f7d399474ca738e0bc96f715 >> Reported-by: Dan Carpenter <[email protected]> >> Signed-off-by: Nadav Amit <[email protected]> >> [Add #ifdef CONFIG_X86_64 to avoid complaints of undefined behavior. - Paolo] >> Signed-off-by: Paolo Bonzini <[email protected]> >> [ kamal: backport to 3.13-stable: omitted WARN_ON fixes (not in 3.13) ] >> Signed-off-by: Kamal Mostafa <[email protected]> >> --- >> arch/x86/kvm/emulate.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c >> index a440bea..4ae37e7 100644 >> --- a/arch/x86/kvm/emulate.c >> +++ b/arch/x86/kvm/emulate.c >> @@ -581,12 +581,14 @@ static inline int assign_eip_far(struct >> x86_emulate_ctxt *ctxt, ulong dst, >> case 4: >> ctxt->_eip = (u32)dst; >> break; >> +#ifdef CONFIG_X86_64 >> case 8: >> if ((cs_l && is_noncanonical_address(dst)) || >> - (!cs_l && (dst & ~(u32)-1))) >> + (!cs_l && (dst >> 32) != 0)) >> return emulate_gp(ctxt, 0); >> ctxt->_eip = dst; >> break; >> +#endif >> default: >> WARN(1, "unsupported eip assignment size\n"); >> } >> -- >> 1.9.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe stable" in >> the body of a message to [email protected] >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > Hi. > > Should the WARN_ON fixes have been included as well in 3.13.11.11? > > WARN_ON hunks were added with the backport of "KVM: x86: Handle errors > when RIP is set during far jumps" in 3.13.11.11 commit > b8ba339d86fb627d54fea929492114d45f6835c2.
If it was added, it should be fixed. The WARN_ON mistakenly has double-negation. Nadav -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
