From: frowand.list@gmail.com To: robh+dt@kernel.org, Michael Bringmann <mwb@linux.vnet.ibm.com>, linuxppc-dev@lists.ozlabs.org Cc: Michael Ellerman <mpe@ellerman.id.au>, Tyrel Datwyler <tyreld@linux.vnet.ibm.com>, Thomas Falcon <tlfalcon@linux.vnet.ibm.com>, Juliet Kim <minkim@us.ibm.com>, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/2] of: of_node_get()/of_node_put() nodes held in phandle cache Date: Sun, 16 Dec 2018 23:56:35 -0800 [thread overview] Message-ID: <1545033396-24485-2-git-send-email-frowand.list@gmail.com> (raw) In-Reply-To: <1545033396-24485-1-git-send-email-frowand.list@gmail.com> From: Frank Rowand <frank.rowand@sony.com> The phandle cache contains struct device_node pointers. The refcount of the pointers was not incremented while in the cache, allowing use after free error after kfree() of the node. Add the proper increment and decrement of the use count. Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Signed-off-by: Frank Rowand <frank.rowand@sony.com> --- changes since v1 - make __of_free_phandle_cache() static drivers/of/base.c | 70 ++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 46 insertions(+), 24 deletions(-) diff --git a/drivers/of/base.c b/drivers/of/base.c index 09692c9b32a7..6c33d63361b8 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -116,9 +116,6 @@ int __weak of_node_to_nid(struct device_node *np) } #endif -static struct device_node **phandle_cache; -static u32 phandle_cache_mask; - /* * Assumptions behind phandle_cache implementation: * - phandle property values are in a contiguous range of 1..n @@ -127,6 +124,44 @@ int __weak of_node_to_nid(struct device_node *np) * - the phandle lookup overhead reduction provided by the cache * will likely be less */ + +static struct device_node **phandle_cache; +static u32 phandle_cache_mask; + +/* + * Caller must hold devtree_lock. + */ +static void __of_free_phandle_cache(void) +{ + u32 cache_entries = phandle_cache_mask + 1; + u32 k; + + if (!phandle_cache) + return; + + for (k = 0; k < cache_entries; k++) + of_node_put(phandle_cache[k]); + + kfree(phandle_cache); + phandle_cache = NULL; +} + +int of_free_phandle_cache(void) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&devtree_lock, flags); + + __of_free_phandle_cache(); + + raw_spin_unlock_irqrestore(&devtree_lock, flags); + + return 0; +} +#if !defined(CONFIG_MODULES) +late_initcall_sync(of_free_phandle_cache); +#endif + void of_populate_phandle_cache(void) { unsigned long flags; @@ -136,8 +171,7 @@ void of_populate_phandle_cache(void) raw_spin_lock_irqsave(&devtree_lock, flags); - kfree(phandle_cache); - phandle_cache = NULL; + __of_free_phandle_cache(); for_each_of_allnodes(np) if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) @@ -155,30 +189,15 @@ void of_populate_phandle_cache(void) goto out; for_each_of_allnodes(np) - if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) + if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) { + of_node_get(np); phandle_cache[np->phandle & phandle_cache_mask] = np; + } out: raw_spin_unlock_irqrestore(&devtree_lock, flags); } -int of_free_phandle_cache(void) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&devtree_lock, flags); - - kfree(phandle_cache); - phandle_cache = NULL; - - raw_spin_unlock_irqrestore(&devtree_lock, flags); - - return 0; -} -#if !defined(CONFIG_MODULES) -late_initcall_sync(of_free_phandle_cache); -#endif - void __init of_core_init(void) { struct device_node *np; @@ -1195,8 +1214,11 @@ struct device_node *of_find_node_by_phandle(phandle handle) if (!np) { for_each_of_allnodes(np) if (np->phandle == handle) { - if (phandle_cache) + if (phandle_cache) { + /* will put when removed from cache */ + of_node_get(np); phandle_cache[masked_handle] = np; + } break; } } -- Frank Rowand <frank.rowand@sony.com>
WARNING: multiple messages have this Message-ID (diff)
From: frowand.list@gmail.com To: robh+dt@kernel.org, Michael Bringmann <mwb@linux.vnet.ibm.com>, linuxppc-dev@lists.ozlabs.org Cc: devicetree@vger.kernel.org, Thomas Falcon <tlfalcon@linux.vnet.ibm.com>, linux-kernel@vger.kernel.org, Juliet Kim <minkim@us.ibm.com>, Tyrel Datwyler <tyreld@linux.vnet.ibm.com> Subject: [PATCH v2 1/2] of: of_node_get()/of_node_put() nodes held in phandle cache Date: Sun, 16 Dec 2018 23:56:35 -0800 [thread overview] Message-ID: <1545033396-24485-2-git-send-email-frowand.list@gmail.com> (raw) In-Reply-To: <1545033396-24485-1-git-send-email-frowand.list@gmail.com> From: Frank Rowand <frank.rowand@sony.com> The phandle cache contains struct device_node pointers. The refcount of the pointers was not incremented while in the cache, allowing use after free error after kfree() of the node. Add the proper increment and decrement of the use count. Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Signed-off-by: Frank Rowand <frank.rowand@sony.com> --- changes since v1 - make __of_free_phandle_cache() static drivers/of/base.c | 70 ++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 46 insertions(+), 24 deletions(-) diff --git a/drivers/of/base.c b/drivers/of/base.c index 09692c9b32a7..6c33d63361b8 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -116,9 +116,6 @@ int __weak of_node_to_nid(struct device_node *np) } #endif -static struct device_node **phandle_cache; -static u32 phandle_cache_mask; - /* * Assumptions behind phandle_cache implementation: * - phandle property values are in a contiguous range of 1..n @@ -127,6 +124,44 @@ int __weak of_node_to_nid(struct device_node *np) * - the phandle lookup overhead reduction provided by the cache * will likely be less */ + +static struct device_node **phandle_cache; +static u32 phandle_cache_mask; + +/* + * Caller must hold devtree_lock. + */ +static void __of_free_phandle_cache(void) +{ + u32 cache_entries = phandle_cache_mask + 1; + u32 k; + + if (!phandle_cache) + return; + + for (k = 0; k < cache_entries; k++) + of_node_put(phandle_cache[k]); + + kfree(phandle_cache); + phandle_cache = NULL; +} + +int of_free_phandle_cache(void) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&devtree_lock, flags); + + __of_free_phandle_cache(); + + raw_spin_unlock_irqrestore(&devtree_lock, flags); + + return 0; +} +#if !defined(CONFIG_MODULES) +late_initcall_sync(of_free_phandle_cache); +#endif + void of_populate_phandle_cache(void) { unsigned long flags; @@ -136,8 +171,7 @@ void of_populate_phandle_cache(void) raw_spin_lock_irqsave(&devtree_lock, flags); - kfree(phandle_cache); - phandle_cache = NULL; + __of_free_phandle_cache(); for_each_of_allnodes(np) if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) @@ -155,30 +189,15 @@ void of_populate_phandle_cache(void) goto out; for_each_of_allnodes(np) - if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) + if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) { + of_node_get(np); phandle_cache[np->phandle & phandle_cache_mask] = np; + } out: raw_spin_unlock_irqrestore(&devtree_lock, flags); } -int of_free_phandle_cache(void) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&devtree_lock, flags); - - kfree(phandle_cache); - phandle_cache = NULL; - - raw_spin_unlock_irqrestore(&devtree_lock, flags); - - return 0; -} -#if !defined(CONFIG_MODULES) -late_initcall_sync(of_free_phandle_cache); -#endif - void __init of_core_init(void) { struct device_node *np; @@ -1195,8 +1214,11 @@ struct device_node *of_find_node_by_phandle(phandle handle) if (!np) { for_each_of_allnodes(np) if (np->phandle == handle) { - if (phandle_cache) + if (phandle_cache) { + /* will put when removed from cache */ + of_node_get(np); phandle_cache[masked_handle] = np; + } break; } } -- Frank Rowand <frank.rowand@sony.com>
next prev parent reply other threads:[~2018-12-17 7:56 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-12-17 7:56 [PATCH v2 0/2] of: phandle_cache, fix refcounts, remove stale entry frowand.list 2018-12-17 7:56 ` frowand.list 2018-12-17 7:56 ` frowand.list [this message] 2018-12-17 7:56 ` [PATCH v2 1/2] of: of_node_get()/of_node_put() nodes held in phandle cache frowand.list 2018-12-17 10:43 ` Michael Ellerman 2018-12-17 10:43 ` Michael Ellerman 2018-12-17 7:56 ` [PATCH v2 2/2] of: __of_detach_node() - remove node from " frowand.list 2018-12-17 7:56 ` frowand.list 2018-12-17 10:52 ` Michael Ellerman 2018-12-17 10:52 ` Michael Ellerman 2018-12-18 18:57 ` Frank Rowand 2018-12-18 18:57 ` Frank Rowand 2018-12-18 20:01 ` Rob Herring 2018-12-18 20:01 ` Rob Herring 2018-12-18 20:09 ` Frank Rowand 2018-12-18 20:09 ` Frank Rowand 2018-12-18 20:33 ` Frank Rowand 2018-12-18 20:33 ` Frank Rowand 2018-12-18 20:58 ` Rob Herring 2018-12-18 20:58 ` Rob Herring 2018-12-18 23:44 ` Michael Ellerman 2018-12-18 23:44 ` Michael Ellerman 2018-12-18 23:44 ` Michael Ellerman 2018-12-18 15:43 ` [PATCH v2 0/2] of: phandle_cache, fix refcounts, remove stale entry Rob Herring 2018-12-18 15:43 ` Rob Herring 2018-12-18 23:46 ` Michael Ellerman 2018-12-18 23:46 ` Michael Ellerman 2018-12-18 23:46 ` Michael Ellerman
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