From 8f5be0ec23bb9ef3f96659c8dff1340b876600bf Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Mon, 13 Aug 2018 09:52:09 +0300 Subject: [PATCH 1/8] kernfs: update comment about kernfs_path() return value Now it returns the length of the full path or error code. Signed-off-by: Konstantin Khlebnikov Fixes: 3abb1d90f5d9 ("kernfs: make kernfs_path*() behave in the style of strlcpy()") Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- include/linux/kernfs.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index 814643f7ee52..5b36b1287a5a 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -477,10 +477,11 @@ static inline void kernfs_init(void) { } * @buf: buffer to copy @kn's name into * @buflen: size of @buf * - * Builds and returns the full path of @kn in @buf of @buflen bytes. The - * path is built from the end of @buf so the returned pointer usually - * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated - * and %NULL is returned. + * If @kn is NULL result will be "(null)". + * + * Returns the length of the full path. If the full length is equal to or + * greater than @buflen, @buf contains the truncated path with the trailing + * '\0'. On error, -errno is returned. */ static inline int kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen) { From be6b1dfe95eda70bd031dc03d420d022fd536d63 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 22 Aug 2018 13:00:07 +0200 Subject: [PATCH 2/8] drivers/base/devtmpfs.c: don't pretend path is const in delete_path path is the result of kstrdup, and we repeatedly call strrchr on it, modifying it through the returned pointer. So there's no reason to pretend path is const. Signed-off-by: Rasmus Villemoes Signed-off-by: Greg Kroah-Hartman --- drivers/base/devtmpfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index f7768077e817..b93fc862d365 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -252,7 +252,7 @@ static int dev_rmdir(const char *name) static int delete_path(const char *nodepath) { - const char *path; + char *path; int err = 0; path = kstrdup(nodepath, GFP_KERNEL); From bdae566d5d9733b6e32b378668b84eadf28a94d4 Mon Sep 17 00:00:00 2001 From: Banajit Goswami Date: Mon, 27 Aug 2018 21:15:39 -0700 Subject: [PATCH 3/8] component: fix loop condition to call unbind() if bind() fails During component_bind_all(), if bind() fails for any particular component associated with a master, unbind() should be called for all previous components in that master's match array, whose bind() might have completed successfully. As per the current logic, if bind() fails for the component at position 'n' in the master's match array, it would start calling unbind() from component in 'n'th position itself and work backwards, and will always skip calling unbind() for component in 0th position in the master's match array. Fix this by updating the loop condition, and the logic to refer to the components in master's match array, so that unbind() is called for all components starting from 'n-1'st position in the array, until (and including) component in 0th position. Signed-off-by: Banajit Goswami Signed-off-by: Greg Kroah-Hartman --- drivers/base/component.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/base/component.c b/drivers/base/component.c index 8946dfee4768..e8d676fad0c9 100644 --- a/drivers/base/component.c +++ b/drivers/base/component.c @@ -536,9 +536,9 @@ int component_bind_all(struct device *master_dev, void *data) } if (ret != 0) { - for (; i--; ) - if (!master->match->compare[i].duplicate) { - c = master->match->compare[i].component; + for (; i > 0; i--) + if (!master->match->compare[i - 1].duplicate) { + c = master->match->compare[i - 1].component; component_unbind(c, master, data); } } From a75e78f21f9ad4b810868c89dbbabcc3931591ca Mon Sep 17 00:00:00 2001 From: Bernd Edlinger Date: Sat, 7 Jul 2018 17:52:47 +0000 Subject: [PATCH 4/8] kernfs: Fix range checks in kernfs_get_target_path The terminating NUL byte is only there because the buffer is allocated with kzalloc(PAGE_SIZE, GFP_KERNEL), but since the range-check is off-by-one, and PAGE_SIZE==PATH_MAX, the returned string may not be zero-terminated if it is exactly PATH_MAX characters long. Furthermore also the initial loop may theoretically exceed PATH_MAX and cause a fault. Signed-off-by: Bernd Edlinger Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/symlink.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c index 305b220af45d..162f43b80c84 100644 --- a/fs/kernfs/symlink.c +++ b/fs/kernfs/symlink.c @@ -72,6 +72,9 @@ static int kernfs_get_target_path(struct kernfs_node *parent, if (base == kn) break; + if ((s - path) + 3 >= PATH_MAX) + return -ENAMETOOLONG; + strcpy(s, "../"); s += 3; base = base->parent; @@ -88,7 +91,7 @@ static int kernfs_get_target_path(struct kernfs_node *parent, if (len < 2) return -EINVAL; len--; - if ((s - path) + len > PATH_MAX) + if ((s - path) + len >= PATH_MAX) return -ENAMETOOLONG; /* reverse fillup of target string from target to base */ From 8514c470dc18e58f27dee10a787175ef8f31162f Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 11 Jul 2018 15:20:32 +0200 Subject: [PATCH 5/8] driver core: add BUS_ATTR_WO() macro Many bus attributes are write-only, so provide a simple macro for that to be able to match the other driver core attribute macros. Cc: "Rafael J. Wysocki" Cc: Ioana Ciornei Signed-off-by: Greg Kroah-Hartman --- include/linux/device.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/device.h b/include/linux/device.h index 8f882549edee..767cf1938b14 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -55,6 +55,8 @@ struct bus_attribute { struct bus_attribute bus_attr_##_name = __ATTR_RW(_name) #define BUS_ATTR_RO(_name) \ struct bus_attribute bus_attr_##_name = __ATTR_RO(_name) +#define BUS_ATTR_WO(_name) \ + struct bus_attribute bus_attr_##_name = __ATTR_WO(_name) extern int __must_check bus_create_file(struct bus_type *, struct bus_attribute *); From 0571967dfb5d2573c2a06871517d748932a899d1 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Sun, 14 Oct 2018 17:20:07 +0200 Subject: [PATCH 6/8] devres: constify p in devm_kfree() Make devm_kfree() signature uniform with that of kfree(). To avoid compiler warnings: cast p to (void *) when calling devres_destroy(). Signed-off-by: Bartosz Golaszewski Reviewed-by: Bjorn Andersson Reviewed-by: Geert Uytterhoeven Acked-by: Rasmus Villemoes Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/base/devres.c | 5 +++-- include/linux/device.h | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/base/devres.c b/drivers/base/devres.c index f98a097e73f2..438c91a43508 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -885,11 +885,12 @@ EXPORT_SYMBOL_GPL(devm_kasprintf); * * Free memory allocated with devm_kmalloc(). */ -void devm_kfree(struct device *dev, void *p) +void devm_kfree(struct device *dev, const void *p) { int rc; - rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p); + rc = devres_destroy(dev, devm_kmalloc_release, + devm_kmalloc_match, (void *)p); WARN_ON(rc); } EXPORT_SYMBOL_GPL(devm_kfree); diff --git a/include/linux/device.h b/include/linux/device.h index 767cf1938b14..c2022c1daef6 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -694,7 +694,7 @@ static inline void *devm_kcalloc(struct device *dev, { return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO); } -extern void devm_kfree(struct device *dev, void *p); +extern void devm_kfree(struct device *dev, const void *p); extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc; extern void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp); From 59c3f82ad1d6ed83fde9d7608afb9fb221a211ab Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Sun, 14 Oct 2018 17:20:08 +0200 Subject: [PATCH 7/8] mm: move is_kernel_rodata() to asm-generic/sections.h Export this routine so that we can use it later in devm_kstrdup_const() and devm_kfree(). Signed-off-by: Bartosz Golaszewski Reviewed-by: Bjorn Andersson Acked-by: Mike Rapoport Acked-by: Rasmus Villemoes Reviewed-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/sections.h | 14 ++++++++++++++ mm/util.c | 7 ------- 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 849cd8eb5ca0..d79abca81a52 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -141,4 +141,18 @@ static inline bool init_section_intersects(void *virt, size_t size) return memory_intersects(__init_begin, __init_end, virt, size); } +/** + * is_kernel_rodata - checks if the pointer address is located in the + * .rodata section + * + * @addr: address to check + * + * Returns: true if the address is located in .rodata, false otherwise. + */ +static inline bool is_kernel_rodata(unsigned long addr) +{ + return addr >= (unsigned long)__start_rodata && + addr < (unsigned long)__end_rodata; +} + #endif /* _ASM_GENERIC_SECTIONS_H_ */ diff --git a/mm/util.c b/mm/util.c index 9e3ebd2ef65f..470f5cd80b64 100644 --- a/mm/util.c +++ b/mm/util.c @@ -15,17 +15,10 @@ #include #include -#include #include #include "internal.h" -static inline int is_kernel_rodata(unsigned long addr) -{ - return addr >= (unsigned long)__start_rodata && - addr < (unsigned long)__end_rodata; -} - /** * kfree_const - conditionally free memory * @x: pointer to the memory From 09d1ea1c7309c8ca91151778bb3efe514f2e03ed Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Sun, 14 Oct 2018 17:20:09 +0200 Subject: [PATCH 8/8] devres: provide devm_kstrdup_const() Provide a resource managed version of kstrdup_const(). This variant internally calls devm_kstrdup() on pointers that are outside of .rodata section and returns the string as is otherwise. Make devm_kfree() check if the passed pointer doesn't point to .rodata and if so - don't actually destroy the resource. Signed-off-by: Bartosz Golaszewski Reviewed-by: Bjorn Andersson Acked-by: Mike Rapoport Acked-by: Rasmus Villemoes Reviewed-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/base/devres.c | 31 +++++++++++++++++++++++++++++++ include/linux/device.h | 2 ++ 2 files changed, 33 insertions(+) diff --git a/drivers/base/devres.c b/drivers/base/devres.c index 438c91a43508..4aaf00d2098b 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -11,6 +11,8 @@ #include #include +#include + #include "base.h" struct devres_node { @@ -822,6 +824,28 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) } EXPORT_SYMBOL_GPL(devm_kstrdup); +/** + * devm_kstrdup_const - resource managed conditional string duplication + * @dev: device for which to duplicate the string + * @s: the string to duplicate + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Strings allocated by devm_kstrdup_const will be automatically freed when + * the associated device is detached. + * + * RETURNS: + * Source string if it is in .rodata section otherwise it falls back to + * devm_kstrdup. + */ +const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp) +{ + if (is_kernel_rodata((unsigned long)s)) + return s; + + return devm_kstrdup(dev, s, gfp); +} +EXPORT_SYMBOL_GPL(devm_kstrdup_const); + /** * devm_kvasprintf - Allocate resource managed space and format a string * into that. @@ -889,6 +913,13 @@ void devm_kfree(struct device *dev, const void *p) { int rc; + /* + * Special case: pointer to a string in .rodata returned by + * devm_kstrdup_const(). + */ + if (unlikely(is_kernel_rodata((unsigned long)p))) + return; + rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, (void *)p); WARN_ON(rc); diff --git a/include/linux/device.h b/include/linux/device.h index c2022c1daef6..fecd9722400e 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -696,6 +696,8 @@ static inline void *devm_kcalloc(struct device *dev, } extern void devm_kfree(struct device *dev, const void *p); extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc; +extern const char *devm_kstrdup_const(struct device *dev, + const char *s, gfp_t gfp); extern void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp);