Fix for tpm usercopy (rhbz 1788653)

2 files changed, 95 insertions, 0 deletions

diff --git a/kernel.spec b/kernel.spec
index b9efdcfa1..439435bfe 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -614,6 +614,9 @@ Patch609: 0002-drm-nouveau-Fix-drm-core-using-atomic-code-paths-on-.patch
 # rhbz 1781288
 Patch610: 0001-tracing-Do-not-create-directories-if-lockdown-is-in-.patch
 
+# rhbz 1788653
+Patch611: tpm-handle-negative-priv--response_len-in-tpm_common_read.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -1851,6 +1854,9 @@ fi
 #
 #
 %changelog
+* Mon Jan 06 2020 Laura Abbott <labbott@redhat.com>
+- Fix for tpm usercopy (rhbz 1788653)
+
 * Mon Jan 06 2020 Hans de Goede <hdegoede@redhat.com>
 - Make the MFD Intel LPSS driver builtin, some devices require this to be
   available early during boot (rhbz#1787997)
diff --git a/tpm-handle-negative-priv--response_len-in-tpm_common_read.patch b/tpm-handle-negative-priv--response_len-in-tpm_common_read.patch
new file mode 100644
index 000000000..40df117ff
--- /dev/null
+++ b/tpm-handle-negative-priv--response_len-in-tpm_common_read.patch
@@ -0,0 +1,89 @@
+From patchwork Tue Jan  7 22:04:48 2020
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+X-Patchwork-Submitter: Tadeusz Struk <tadeusz.struk@intel.com>
+X-Patchwork-Id: 1176682
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+Subject: [PATCH] tpm: handle negative priv->response_len in tpm_common_read
+From: Tadeusz Struk <tadeusz.struk@intel.com>
+To: jarkko.sakkinen@linux.intel.com
+Cc: keescook@chromium.org, tadeusz.struk@intel.com,
+        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
+        linux-integrity@vger.kernel.org, labbott@redhat.com
+Date: Tue, 07 Jan 2020 14:04:48 -0800
+Message-ID: <157843468820.24718.10808226634364669421.stgit@tstruk-mobl1>
+In-Reply-To: <b85fa669-d3aa-f6c9-9631-988ae47e392c@redhat.com>
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+
+The priv->responce_length can hold the size of an response or
+an negative error code, and the tpm_common_read() needs to handle
+both cases correctly. Changed the type of responce_length to
+signed and accounted for negative value in tpm_common_read()
+
+Cc: stable@vger.kernel.org
+Fixes: d23d12484307 ("tpm: fix invalid locking in NONBLOCKING mode")
+Reported-by: Laura Abbott <labbott@redhat.com>
+Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
+Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+---
+ drivers/char/tpm/tpm-dev-common.c |    2 +-
+ drivers/char/tpm/tpm-dev.h        |    2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
+index b23b0b999232..87f449340202 100644
+--- a/drivers/char/tpm/tpm-dev-common.c
++++ b/drivers/char/tpm/tpm-dev-common.c
+@@ -130,7 +130,7 @@ ssize_t tpm_common_read(struct file *file, char __user *buf,
+ 		priv->response_read = true;
+ 
+ 		ret_size = min_t(ssize_t, size, priv->response_length);
+-		if (!ret_size) {
++		if (ret_size <= 0) {
+ 			priv->response_length = 0;
+ 			goto out;
+ 		}
+diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h
+index 1089fc0bb290..f3742bcc73e3 100644
+--- a/drivers/char/tpm/tpm-dev.h
++++ b/drivers/char/tpm/tpm-dev.h
+@@ -14,7 +14,7 @@ struct file_priv {
+ 	struct work_struct timeout_work;
+ 	struct work_struct async_work;
+ 	wait_queue_head_t async_wait;
+-	size_t response_length;
++	ssize_t response_length;
+ 	bool response_read;
+ 	bool command_enqueued;
+