diff options
| author | Hyunwook (Wooky) Baek <baekhw@google.com> | 2021-01-09 23:11:02 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-27 11:55:28 +0100 |
| commit | 5cc760632083f2ee80ce6c098c6afd492120227e (patch) | |
| tree | 670ab72baef6d17d2da357fd61b6fa1d12112a7a /arch | |
| parent | 6c19578d46346aa709d954fa30268139034fa57b (diff) | |
x86/sev-es: Handle string port IO to kernel memory properly
commit 7024f60d655272bd2ca1d3a4c9e0a63319b1eea1 upstream.
Don't assume dest/source buffers are userspace addresses when manually
copying data for string I/O or MOVS MMIO, as {get,put}_user() will fail
if handed a kernel address and ultimately lead to a kernel panic.
When invoking INSB/OUTSB instructions in kernel space in a
SEV-ES-enabled VM, the kernel crashes with the following message:
"SEV-ES: Unsupported exception in #VC instruction emulation - can't continue"
Handle that case properly.
[ bp: Massage commit message. ]
Fixes: f980f9c31a92 ("x86/sev-es: Compile early handler code into kernel image")
Signed-off-by: Hyunwook (Wooky) Baek <baekhw@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Link: https://lkml.kernel.org/r/20210110071102.2576186-1-baekhw@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/sev-es.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 42bb0db62aab..84c1821819af 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -286,6 +286,12 @@ static enum es_result vc_write_mem(struct es_em_ctxt *ctxt, u16 d2; u8 d1; + /* If instruction ran in kernel mode and the I/O buffer is in kernel space */ + if (!user_mode(ctxt->regs) && !access_ok(target, size)) { + memcpy(dst, buf, size); + return ES_OK; + } + switch (size) { case 1: memcpy(&d1, buf, 1); @@ -335,6 +341,12 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, u16 d2; u8 d1; + /* If instruction ran in kernel mode and the I/O buffer is in kernel space */ + if (!user_mode(ctxt->regs) && !access_ok(s, size)) { + memcpy(buf, src, size); + return ES_OK; + } + switch (size) { case 1: if (get_user(d1, s)) |