On Tue, Apr 17, 2018 at 1:24 AM, Christian Borntraeger <[email protected]> wrote: > > > On 04/17/2018 10:20 AM, Thomas Richter wrote: >> In kernel v4.16.0 the module .text address is displayed >> wrong when using /sys/module/*/sections/.text file. >> Commit ef0010a30935 ("vsprintf: don't use 'restricted_pointer()' when >> not restricting") >> is the first bad commit. >> >> Here is the issue, using module qeth_l2 on s390 which is the >> ethernet device driver: >> >> [root@s35lp76 ~]# lsmod >> Module Size Used by >> qeth_l2 94208 1 >> ... >> >> [root@s35lp76 ~]# cat /proc/modules | egrep '^qeth_l2' >> qeth_l2 94208 1 - Live 0x000003ff80401000 >> ^ This is the correct address in memory >> [root@s35lp76 ~]# cat /sys/module/qeth_l2/sections/.text >> 0x0000000018ea8363 <---- This is a wrong address >> [root@s35lp76 ~]# >> >> This breaks the perf tool which uses this address on s390 >> to calculate start of .text section in memory. >> >> Fix this by printing the correct (unhashed) address. >> >> Thanks to Jessica Yu for helping on this. >> >> Suggested-by: Linus Torvalds <[email protected]> >> Signed-off-by: Thomas Richter <[email protected]> >> Cc: Jessica Yu <[email protected]> > > CC stable? > >> --- >> kernel/module.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/kernel/module.c b/kernel/module.c >> index a6e43a5806a1..77ab7211ddef 100644 >> --- a/kernel/module.c >> +++ b/kernel/module.c >> @@ -1472,7 +1472,7 @@ static ssize_t module_sect_show(struct >> module_attribute *mattr, >> { >> struct module_sect_attr *sattr = >> container_of(mattr, struct module_sect_attr, mattr); >> - return sprintf(buf, "0x%pK\n", (void *)sattr->address); >> + return sprintf(buf, "%#lx\n", kptr_restrict < 2 ? sattr->address : 0);
Can we use %px instead, just to make the hash-bypass reports easier to grep for? -Kees >> } >> >> static void free_sect_attrs(struct module_sect_attrs *sect_attrs) >> > -- Kees Cook Pixel Security
