From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit 84842911322fc6a02a03ab9e728a48c691fe3efd ]
Although kptr_restrict is set to 0 and the kernel is booted with no_hash_pointers parameter, the content of /proc/vmallocinfo is lacking the real addresses.
/ # cat /proc/vmallocinfo 0x(ptrval)-0x(ptrval) 8192 load_module+0xc0c/0x2c0c pages=1 vmalloc 0x(ptrval)-0x(ptrval) 12288 start_kernel+0x4e0/0x690 pages=2 vmalloc 0x(ptrval)-0x(ptrval) 12288 start_kernel+0x4e0/0x690 pages=2 vmalloc 0x(ptrval)-0x(ptrval) 8192 _mpic_map_mmio.constprop.0+0x20/0x44 phys=0x80041000 ioremap 0x(ptrval)-0x(ptrval) 12288 _mpic_map_mmio.constprop.0+0x20/0x44 phys=0x80041000 ioremap ...
According to the documentation for /proc/sys/kernel/, %pK is equivalent to %p when kptr_restrict is set to 0.
Fixes: 5ead723a20e0 ("lib/vsprintf: no_hash_pointers prints all addresses as unhashed") Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Reviewed-by: Petr Mladek pmladek@suse.com Signed-off-by: Petr Mladek pmladek@suse.com Link: https://lore.kernel.org/r/107476128e59bff11a309b5bf7579a1753a41aca.164508760... Signed-off-by: Sasha Levin sashal@kernel.org --- .../admin-guide/kernel-parameters.txt | 3 +- lib/vsprintf.c | 36 +++++++++++-------- 2 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ed55ea20352b..bb25aae69860 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3452,8 +3452,7 @@ difficult since unequal pointers can no longer be compared. However, if this command-line option is specified, then all normal pointers will have their true - value printed. Pointers printed via %pK may still be - hashed. This option should only be specified when + value printed. This option should only be specified when debugging the kernel. Please do not use on production kernels.
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 0621bbb20e0f..a3b73f28b7a9 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -54,6 +54,10 @@ #include <linux/string_helpers.h> #include "kstrtox.h"
+/* Disable pointer hashing if requested */ +bool no_hash_pointers __ro_after_init; +EXPORT_SYMBOL_GPL(no_hash_pointers); + static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base) { const char *cp; @@ -848,6 +852,19 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr, return pointer_string(buf, end, (const void *)hashval, spec); }
+static char *default_pointer(char *buf, char *end, const void *ptr, + struct printf_spec spec) +{ + /* + * default is to _not_ leak addresses, so hash before printing, + * unless no_hash_pointers is specified on the command line. + */ + if (unlikely(no_hash_pointers)) + return pointer_string(buf, end, ptr, spec); + + return ptr_to_id(buf, end, ptr, spec); +} + int kptr_restrict __read_mostly;
static noinline_for_stack @@ -857,7 +874,7 @@ char *restricted_pointer(char *buf, char *end, const void *ptr, switch (kptr_restrict) { case 0: /* Handle as %p, hash and do _not_ leak addresses. */ - return ptr_to_id(buf, end, ptr, spec); + return default_pointer(buf, end, ptr, spec); case 1: { const struct cred *cred;
@@ -2226,10 +2243,6 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, return widen_string(buf, buf - buf_start, end, spec); }
-/* Disable pointer hashing if requested */ -bool no_hash_pointers __ro_after_init; -EXPORT_SYMBOL_GPL(no_hash_pointers); - int __init no_hash_pointers_enable(char *str) { if (no_hash_pointers) @@ -2458,7 +2471,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'e': /* %pe with a non-ERR_PTR gets treated as plain %p */ if (!IS_ERR(ptr)) - break; + return default_pointer(buf, end, ptr, spec); return err_ptr(buf, end, ptr, spec); case 'u': case 'k': @@ -2468,16 +2481,9 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, default: return error_string(buf, end, "(einval)", spec); } + default: + return default_pointer(buf, end, ptr, spec); } - - /* - * default is to _not_ leak addresses, so hash before printing, - * unless no_hash_pointers is specified on the command line. - */ - if (unlikely(no_hash_pointers)) - return pointer_string(buf, end, ptr, spec); - else - return ptr_to_id(buf, end, ptr, spec); }
/*