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authorRick Edgecombe <rick.p.edgecombe@intel.com>2024-03-11 17:15:54 +0100
committerWei Liu <wei.liu@kernel.org>2024-04-10 23:33:32 +0200
commit03f5a999adba062456c8c818a683beb1b498983a (patch)
tree68fd0e11190f3d3b803120c2dc25d40b3e48b23e
parenthv/hv_kvp_daemon: Handle IPv4 and Ipv6 combination for keyfile format (diff)
downloadlinux-03f5a999adba062456c8c818a683beb1b498983a.tar.xz
linux-03f5a999adba062456c8c818a683beb1b498983a.zip
Drivers: hv: vmbus: Leak pages if set_memory_encrypted() fails
In CoCo VMs it is possible for the untrusted host to cause set_memory_encrypted() or set_memory_decrypted() to fail such that an error is returned and the resulting memory is shared. Callers need to take care to handle these errors to avoid returning decrypted (shared) memory to the page allocator, which could lead to functional or security issues. VMBus code could free decrypted pages if set_memory_encrypted()/decrypted() fails. Leak the pages if this happens. Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lore.kernel.org/r/20240311161558.1310-2-mhklinux@outlook.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20240311161558.1310-2-mhklinux@outlook.com>
-rw-r--r--drivers/hv/connection.c29
1 files changed, 22 insertions, 7 deletions
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 3cabeeabb1ca..f001ae880e1d 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -237,8 +237,17 @@ int vmbus_connect(void)
vmbus_connection.monitor_pages[0], 1);
ret |= set_memory_decrypted((unsigned long)
vmbus_connection.monitor_pages[1], 1);
- if (ret)
+ if (ret) {
+ /*
+ * If set_memory_decrypted() fails, the encryption state
+ * of the memory is unknown. So leak the memory instead
+ * of risking returning decrypted memory to the free list.
+ * For simplicity, always handle both pages the same.
+ */
+ vmbus_connection.monitor_pages[0] = NULL;
+ vmbus_connection.monitor_pages[1] = NULL;
goto cleanup;
+ }
/*
* Set_memory_decrypted() will change the memory contents if
@@ -337,13 +346,19 @@ void vmbus_disconnect(void)
vmbus_connection.int_page = NULL;
}
- set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1);
- set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1);
+ if (vmbus_connection.monitor_pages[0]) {
+ if (!set_memory_encrypted(
+ (unsigned long)vmbus_connection.monitor_pages[0], 1))
+ hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
+ vmbus_connection.monitor_pages[0] = NULL;
+ }
- hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
- hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
- vmbus_connection.monitor_pages[0] = NULL;
- vmbus_connection.monitor_pages[1] = NULL;
+ if (vmbus_connection.monitor_pages[1]) {
+ if (!set_memory_encrypted(
+ (unsigned long)vmbus_connection.monitor_pages[1], 1))
+ hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
+ vmbus_connection.monitor_pages[1] = NULL;
+ }
}
/*