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authorTimur Tabi <timur@kernel.org>2021-02-14 10:13:48 -0600
committerPetr Mladek <pmladek@suse.com>2021-02-15 11:08:32 +0100
commit5ead723a20e0447bc7db33dc3070b420e5f80aa6 (patch)
tree48c75744ea69ab8a453743e41ab00d3c8a642839 /lib/test_printf.c
parentd9d4de2309cd1721421c6488f1bb5744d2c83a39 (diff)
lib/vsprintf: no_hash_pointers prints all addresses as unhashed
If the no_hash_pointers command line parameter is set, then printk("%p") will print pointers as unhashed, which is useful for debugging purposes. This change applies to any function that uses vsprintf, such as print_hex_dump() and seq_buf_printf(). A large warning message is displayed if this option is enabled. Unhashed pointers expose kernel addresses, which can be a security risk. Also update test_printf to skip the hashed pointer tests if the command-line option is set. Signed-off-by: Timur Tabi <timur@kernel.org> Acked-by: Petr Mladek <pmladek@suse.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Marco Elver <elver@google.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210214161348.369023-4-timur@kernel.org
Diffstat (limited to 'lib/test_printf.c')
-rw-r--r--lib/test_printf.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/lib/test_printf.c b/lib/test_printf.c
index ad2bcfa8caa1..a6755798e9e6 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -35,6 +35,8 @@ KSTM_MODULE_GLOBALS();
static char *test_buffer __initdata;
static char *alloced_buffer __initdata;
+extern bool no_hash_pointers;
+
static int __printf(4, 0) __init
do_test(int bufsize, const char *expect, int elen,
const char *fmt, va_list ap)
@@ -301,6 +303,12 @@ plain(void)
{
int err;
+ if (no_hash_pointers) {
+ pr_warn("skipping plain 'p' tests");
+ skipped_tests += 2;
+ return;
+ }
+
err = plain_hash();
if (err) {
pr_warn("plain 'p' does not appear to be hashed\n");