The patch titled
Subject: vsprintf: kptr_restrict is okay in IRQ when 2
has been added to the -mm tree. Its filename is
vsprintf-kptr_restrict-is-okay-in-irq-when-2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/vsprintf-kptr_restrict-is-okay-in-irq-when-2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/vsprintf-kptr_restrict-is-okay-in-irq-when-2.patch
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------------------------------------------------------
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Subject: vsprintf: kptr_restrict is okay in IRQ when 2
The kptr_restrict flag, when set to 1, only prints the kernel address when
the user has CAP_SYSLOG. When it is set to 2, the kernel address is
always printed as zero. When set to 1, this needs to check whether or not
we're in IRQ. However, when set to 2, this check is unneccessary, and
produces confusing results in dmesg. Thus, only make sure we're not in
IRQ when mode 1 is used, but not mode 2.
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/vsprintf.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff -puN lib/vsprintf.c~vsprintf-kptr_restrict-is-okay-in-irq-when-2 lib/vsprintf.c
--- a/lib/vsprintf.c~vsprintf-kptr_restrict-is-okay-in-irq-when-2
+++ a/lib/vsprintf.c
@@ -1663,22 +1663,23 @@ char *pointer(const char *fmt, char *buf
return buf;
}
case 'K':
- /*
- * %pK cannot be used in IRQ context because its test
- * for CAP_SYSLOG would be meaningless.
- */
- if (kptr_restrict && (in_irq() || in_serving_softirq() ||
- in_nmi())) {
- if (spec.field_width == -1)
- spec.field_width = default_width;
- return string(buf, end, "pK-error", spec);
- }
-
switch (kptr_restrict) {
case 0:
/* Always print %pK values */
break;
case 1: {
+ const struct cred *cred;
+
+ /*
+ * kptr_restrict==1 cannot be used in IRQ context because
+ * its test for CAP_SYSLOG would be meaningless.
+ */
+ if (in_irq() || in_serving_softirq() || in_nmi()) {
+ if (spec.field_width == -1)
+ spec.field_width = default_width;
+ return string(buf, end, "pK-error", spec);
+ }
+
/*
* Only print the real pointer value if the current
* process has CAP_SYSLOG and is running with the
@@ -1688,8 +1689,7 @@ char *pointer(const char *fmt, char *buf
* leak pointer values if a binary opens a file using
* %pK and then elevates privileges before reading it.
*/
- const struct cred *cred = current_cred();
-
+ cred = current_cred();
if (!has_capability_noaudit(current, CAP_SYSLOG) ||
!uid_eq(cred->euid, cred->uid) ||
!gid_eq(cred->egid, cred->gid))
_
Patches currently in -mm which might be from Jason@xxxxxxxxx are
vsprintf-kptr_restrict-is-okay-in-irq-when-2.patch
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