102 lines
4.0 KiB
Diff
102 lines
4.0 KiB
Diff
From c52d8916b34838e6d6dcd72b7712e6aa28c8daf4 Mon Sep 17 00:00:00 2001
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From: "William A. Kennington III" <wak@google.com>
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Date: Wed, 7 Apr 2021 02:55:27 -0700
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Subject: [PATCH 103/109] spi: Fix use-after-free with devm_spi_alloc_*
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mainline inclusion
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from mainline-v5.13-rc1
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commit 794aaf01444d4e765e2b067cba01cc69c1c68ed9
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category: bugfix
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bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8DDF5
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Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=794aaf01444d4e765e2b067cba01cc69c1c68ed9
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----------------------------------------------------------------------
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We can't rely on the contents of the devres list during
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spi_unregister_controller(), as the list is already torn down at the
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time we perform devres_find() for devm_spi_release_controller. This
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causes devices registered with devm_spi_alloc_{master,slave}() to be
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mistakenly identified as legacy, non-devm managed devices and have their
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reference counters decremented below 0.
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------------[ cut here ]------------
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WARNING: CPU: 1 PID: 660 at lib/refcount.c:28 refcount_warn_saturate+0x108/0x174
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[<b0396f04>] (refcount_warn_saturate) from [<b03c56a4>] (kobject_put+0x90/0x98)
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[<b03c5614>] (kobject_put) from [<b0447b4c>] (put_device+0x20/0x24)
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r4:b6700140
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[<b0447b2c>] (put_device) from [<b07515e8>] (devm_spi_release_controller+0x3c/0x40)
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[<b07515ac>] (devm_spi_release_controller) from [<b045343c>] (release_nodes+0x84/0xc4)
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r5:b6700180 r4:b6700100
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[<b04533b8>] (release_nodes) from [<b0454160>] (devres_release_all+0x5c/0x60)
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r8:b1638c54 r7:b117ad94 r6:b1638c10 r5:b117ad94 r4:b163dc10
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[<b0454104>] (devres_release_all) from [<b044e41c>] (__device_release_driver+0x144/0x1ec)
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r5:b117ad94 r4:b163dc10
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[<b044e2d8>] (__device_release_driver) from [<b044f70c>] (device_driver_detach+0x84/0xa0)
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r9:00000000 r8:00000000 r7:b117ad94 r6:b163dc54 r5:b1638c10 r4:b163dc10
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[<b044f688>] (device_driver_detach) from [<b044d274>] (unbind_store+0xe4/0xf8)
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Instead, determine the devm allocation state as a flag on the
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controller which is guaranteed to be stable during cleanup.
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Fixes: 5e844cc37a5c ("spi: Introduce device-managed SPI controller allocation")
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Signed-off-by: William A. Kennington III <wak@google.com>
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Link: https://lore.kernel.org/r/20210407095527.2771582-1-wak@google.com
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Signed-off-by: Mark Brown <broonie@kernel.org>
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Signed-off-by: Jiang Yi <jiangyi38@hisilicon.com>
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---
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drivers/spi/spi.c | 9 ++-------
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include/linux/spi/spi.h | 3 +++
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2 files changed, 5 insertions(+), 7 deletions(-)
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diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
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index aa50cc5380cf..d2334bfae076 100644
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--- a/drivers/spi/spi.c
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+++ b/drivers/spi/spi.c
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@@ -2084,6 +2084,7 @@ struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
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ctlr = __spi_alloc_controller(dev, size, slave);
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if (ctlr) {
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+ ctlr->devm_allocated = true;
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*ptr = ctlr;
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devres_add(dev, ptr);
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} else {
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@@ -2344,11 +2345,6 @@ int devm_spi_register_controller(struct device *dev,
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}
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EXPORT_SYMBOL_GPL(devm_spi_register_controller);
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-static int devm_spi_match_controller(struct device *dev, void *res, void *ctlr)
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-{
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- return *(struct spi_controller **)res == ctlr;
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-}
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-
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static int __unregister(struct device *dev, void *null)
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{
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spi_unregister_device(to_spi_device(dev));
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@@ -2395,8 +2391,7 @@ void spi_unregister_controller(struct spi_controller *ctlr)
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/* Release the last reference on the controller if its driver
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* has not yet been converted to devm_spi_alloc_master/slave().
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*/
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- if (!devres_find(ctlr->dev.parent, devm_spi_release_controller,
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- devm_spi_match_controller, ctlr))
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+ if (!ctlr->devm_allocated)
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put_device(&ctlr->dev);
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/* free bus id */
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diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
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index 085c8e0e0864..3e51ae8bb26e 100644
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--- a/include/linux/spi/spi.h
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+++ b/include/linux/spi/spi.h
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@@ -450,6 +450,9 @@ struct spi_controller {
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#define SPI_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */
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+ /* flag indicating this is a non-devres managed controller */
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+ bool devm_allocated;
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+
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/* flag indicating this is an SPI slave controller */
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bool slave;
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--
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2.23.0
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