From 7bd57fbc4a4ddedc664cad0bbced1b469e24e921 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Tue, 19 May 2020 13:26:57 +0200 Subject: vsprintf: don't obfuscate NULL and error pointers I don't see what security concern is addressed by obfuscating NULL and IS_ERR() error pointers, printed with %p/%pK. Given the number of sites where %p is used (over 10000) and the fact that NULL pointers aren't uncommon, it probably wouldn't take long for an attacker to find the hash that corresponds to 0. Although harder, the same goes for most common error values, such as -1, -2, -11, -14, etc. The NULL part actually fixes a regression: NULL pointers weren't obfuscated until commit 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid pointers") which went into 5.2. I'm tacking the IS_ERR() part on here because error pointers won't leak kernel addresses and printing them as pointers shouldn't be any different from e.g. %d with PTR_ERR_OR_ZERO(). Obfuscating them just makes debugging based on existing pr_debug and friends excruciating. Note that the "always print 0's for %pK when kptr_restrict == 2" behaviour which goes way back is left as is. Example output with the patch applied: ptr error-ptr NULL %p: 0000000001f8cc5b fffffffffffffff2 0000000000000000 %pK, kptr = 0: 0000000001f8cc5b fffffffffffffff2 0000000000000000 %px: ffff888048c04020 fffffffffffffff2 0000000000000000 %pK, kptr = 1: ffff888048c04020 fffffffffffffff2 0000000000000000 %pK, kptr = 2: 0000000000000000 0000000000000000 0000000000000000 Fixes: 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid pointers") Signed-off-by: Ilya Dryomov Reviewed-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Reviewed-by: Andy Shevchenko Acked-by: Steven Rostedt (VMware) Signed-off-by: Linus Torvalds --- lib/test_printf.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'lib/test_printf.c') diff --git a/lib/test_printf.c b/lib/test_printf.c index 2d9f520d2f27..6b1622f4d7c2 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -214,6 +214,7 @@ test_string(void) #define PTR_STR "ffff0123456789ab" #define PTR_VAL_NO_CRNG "(____ptrval____)" #define ZEROS "00000000" /* hex 32 zero bits */ +#define ONES "ffffffff" /* hex 32 one bits */ static int __init plain_format(void) @@ -245,6 +246,7 @@ plain_format(void) #define PTR_STR "456789ab" #define PTR_VAL_NO_CRNG "(ptrval)" #define ZEROS "" +#define ONES "" static int __init plain_format(void) @@ -330,14 +332,28 @@ test_hashed(const char *fmt, const void *p) test(buf, fmt, p); } +/* + * NULL pointers aren't hashed. + */ static void __init null_pointer(void) { - test_hashed("%p", NULL); + test(ZEROS "00000000", "%p", NULL); test(ZEROS "00000000", "%px", NULL); test("(null)", "%pE", NULL); } +/* + * Error pointers aren't hashed. + */ +static void __init +error_pointer(void) +{ + test(ONES "fffffff5", "%p", ERR_PTR(-11)); + test(ONES "fffffff5", "%px", ERR_PTR(-11)); + test("(efault)", "%pE", ERR_PTR(-11)); +} + #define PTR_INVALID ((void *)0x000000ab) static void __init @@ -649,6 +665,7 @@ test_pointer(void) { plain(); null_pointer(); + error_pointer(); invalid_pointer(); symbol_ptr(); kernel_ptr(); -- cgit v1.2.3 From 7daac5b2fdf88e3c3e84cf0d577f524beb0244ab Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 15 Apr 2020 20:00:44 +0300 Subject: lib/vsprintf: Print time64_t in human readable format There are users which print time and date represented by content of time64_t type in human readable format. Instead of open coding that each time introduce %ptT[dt][r] specifier. Few test cases for %ptT specifier has been added as well. Link: https://lore.kernel.org/r/20200415170046.33374-2-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Reviewed-by: Alexandre Belloni Acked-by: Sergey Senozhatsky Rewieved-by: Petr Mladek Signed-off-by: Petr Mladek --- Documentation/core-api/printk-formats.rst | 22 ++++++++++++---------- lib/test_printf.c | 13 ++++++++++--- lib/vsprintf.c | 31 +++++++++++++++++++++++++++++-- 3 files changed, 51 insertions(+), 15 deletions(-) (limited to 'lib/test_printf.c') diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 8ebe46b1af39..a407cdd09083 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -468,21 +468,23 @@ Examples (OF):: %pfwf /ocp@68000000/i2c@48072000/camera@10/port/endpoint - Full name %pfwP endpoint - Node name -Time and date (struct rtc_time) -------------------------------- +Time and date +------------- :: - %ptR YYYY-mm-ddTHH:MM:SS - %ptRd YYYY-mm-dd - %ptRt HH:MM:SS - %ptR[dt][r] + %pt[RT] YYYY-mm-ddTHH:MM:SS + %pt[RT]d YYYY-mm-dd + %pt[RT]t HH:MM:SS + %pt[RT][dt][r] -For printing date and time as represented by struct rtc_time structure in -human readable format. +For printing date and time as represented by + R struct rtc_time structure + T time64_t type +in human readable format. -By default year will be incremented by 1900 and month by 1. Use %ptRr (raw) -to suppress this behaviour. +By default year will be incremented by 1900 and month by 1. +Use %pt[RT]r (raw) to suppress this behaviour. Passed by reference. diff --git a/lib/test_printf.c b/lib/test_printf.c index 2d9f520d2f27..6dc0a6c33b8c 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -478,7 +478,7 @@ struct_va_format(void) } static void __init -struct_rtc_time(void) +time_and_date(void) { /* 1543210543 */ const struct rtc_time tm = { @@ -489,14 +489,21 @@ struct_rtc_time(void) .tm_mon = 10, .tm_year = 118, }; + /* 2019-01-04T15:32:23 */ + time64_t t = 1546615943; - test("(%ptR?)", "%pt", &tm); + test("(%pt?)", "%pt", &tm); test("2018-11-26T05:35:43", "%ptR", &tm); test("0118-10-26T05:35:43", "%ptRr", &tm); test("05:35:43|2018-11-26", "%ptRt|%ptRd", &tm, &tm); test("05:35:43|0118-10-26", "%ptRtr|%ptRdr", &tm, &tm); test("05:35:43|2018-11-26", "%ptRttr|%ptRdtr", &tm, &tm); test("05:35:43 tr|2018-11-26 tr", "%ptRt tr|%ptRd tr", &tm, &tm); + + test("2019-01-04T15:32:23", "%ptT", &t); + test("0119-00-04T15:32:23", "%ptTr", &t); + test("15:32:23|2019-01-04", "%ptTt|%ptTd", &t, &t); + test("15:32:23|0119-00-04", "%ptTtr|%ptTdr", &t, &t); } static void __init @@ -661,7 +668,7 @@ test_pointer(void) uuid(); dentry(); struct_va_format(); - struct_rtc_time(); + time_and_date(); struct_clk(); bitmap(); netdev_features(); diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 7c488a1ce318..adbcca9c9cba 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -1819,6 +1820,29 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm, return buf; } +static noinline_for_stack +char *time64_str(char *buf, char *end, const time64_t time, + struct printf_spec spec, const char *fmt) +{ + struct rtc_time rtc_time; + struct tm tm; + + time64_to_tm(time, 0, &tm); + + rtc_time.tm_sec = tm.tm_sec; + rtc_time.tm_min = tm.tm_min; + rtc_time.tm_hour = tm.tm_hour; + rtc_time.tm_mday = tm.tm_mday; + rtc_time.tm_mon = tm.tm_mon; + rtc_time.tm_year = tm.tm_year; + rtc_time.tm_wday = tm.tm_wday; + rtc_time.tm_yday = tm.tm_yday; + + rtc_time.tm_isdst = 0; + + return rtc_str(buf, end, &rtc_time, spec, fmt); +} + static noinline_for_stack char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec, const char *fmt) @@ -1826,8 +1850,10 @@ char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec, switch (fmt[1]) { case 'R': return rtc_str(buf, end, (const struct rtc_time *)ptr, spec, fmt); + case 'T': + return time64_str(buf, end, *(const time64_t *)ptr, spec, fmt); default: - return error_string(buf, end, "(%ptR?)", spec); + return error_string(buf, end, "(%pt?)", spec); } } @@ -2143,8 +2169,9 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, * - 'd[234]' For a dentry name (optionally 2-4 last components) * - 'D[234]' Same as 'd' but for a struct file * - 'g' For block_device name (gendisk + partition number) - * - 't[R][dt][r]' For time and date as represented: + * - 't[RT][dt][r]' For time and date as represented by: * R struct rtc_time + * T time64_t * - 'C' For a clock, it prints the name (Common Clock Framework) or address * (legacy clock framework) of the clock * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address -- cgit v1.2.3 From 46d26819a5056f4831649c5887ad5c71a16d86f7 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sun, 24 May 2020 17:30:40 +0200 Subject: software node: implement software_node_unregister() Sometimes it is better to unregister individual nodes instead of trying to do them all at once with software_node_unregister_nodes(), so create software_node_unregister() so that you can unregister them one at a time. This is especially important when creating nodes in a hierarchy, with parent -> children representations. Children always need to be removed before a parent is, as the swnode logic assumes this is going to be the case. Fix up the lib/test_printf.c fwnode_pointer() test which to use this new function as it had the problem of tearing things down in the backwards order. Fixes: f1ce39df508d ("lib/test_printf: Add tests for %pfw printk modifier") Cc: stable Cc: Andy Shevchenko Cc: Brendan Higgins Cc: Dmitry Torokhov Cc: Petr Mladek Cc: Rafael J. Wysocki Cc: Rasmus Villemoes Cc: Sakari Ailus Cc: Sergey Senozhatsky Cc: Steven Rostedt Reported-by: Naresh Kamboju Reported-by: kernel test robot Reported-by: Randy Dunlap Tested-by: Petr Mladek Tested-by: Randy Dunlap Tested-by: Guenter Roeck Reviewed-by: Heikki Krogerus Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/20200524153041.2361-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/swnode.c | 27 +++++++++++++++++++++------ include/linux/property.h | 1 + lib/test_printf.c | 4 +++- 3 files changed, 25 insertions(+), 7 deletions(-) (limited to 'lib/test_printf.c') diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index de8d3543e8fe..770b1f47a625 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -712,17 +712,18 @@ EXPORT_SYMBOL_GPL(software_node_register_nodes); * @nodes: Zero terminated array of software nodes to be unregistered * * Unregister multiple software nodes at once. + * + * NOTE: Be careful using this call if the nodes had parent pointers set up in + * them before registering. If so, it is wiser to remove the nodes + * individually, in the correct order (child before parent) instead of relying + * on the sequential order of the list of nodes in the array. */ void software_node_unregister_nodes(const struct software_node *nodes) { - struct swnode *swnode; int i; - for (i = 0; nodes[i].name; i++) { - swnode = software_node_to_swnode(&nodes[i]); - if (swnode) - fwnode_remove_software_node(&swnode->fwnode); - } + for (i = 0; nodes[i].name; i++) + software_node_unregister(&nodes[i]); } EXPORT_SYMBOL_GPL(software_node_unregister_nodes); @@ -741,6 +742,20 @@ int software_node_register(const struct software_node *node) } EXPORT_SYMBOL_GPL(software_node_register); +/** + * software_node_unregister - Unregister static software node + * @node: The software node to be unregistered + */ +void software_node_unregister(const struct software_node *node) +{ + struct swnode *swnode; + + swnode = software_node_to_swnode(node); + if (swnode) + fwnode_remove_software_node(&swnode->fwnode); +} +EXPORT_SYMBOL_GPL(software_node_unregister); + struct fwnode_handle * fwnode_create_software_node(const struct property_entry *properties, const struct fwnode_handle *parent) diff --git a/include/linux/property.h b/include/linux/property.h index d86de017c689..0d4099b4ce1f 100644 --- a/include/linux/property.h +++ b/include/linux/property.h @@ -441,6 +441,7 @@ int software_node_register_nodes(const struct software_node *nodes); void software_node_unregister_nodes(const struct software_node *nodes); int software_node_register(const struct software_node *node); +void software_node_unregister(const struct software_node *node); int software_node_notify(struct device *dev, unsigned long action); diff --git a/lib/test_printf.c b/lib/test_printf.c index 6b1622f4d7c2..fc63b8959d42 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -637,7 +637,9 @@ static void __init fwnode_pointer(void) test(second_name, "%pfwP", software_node_fwnode(&softnodes[1])); test(third_name, "%pfwP", software_node_fwnode(&softnodes[2])); - software_node_unregister_nodes(softnodes); + software_node_unregister(&softnodes[2]); + software_node_unregister(&softnodes[1]); + software_node_unregister(&softnodes[0]); } static void __init -- cgit v1.2.3