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authorJason A. Donenfeld <Jason@zx2c4.com>2016-02-12 03:13:00 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-02-12 05:35:48 +0300
commit7eb391299419a03cbe0fa5ab0e6b0932e42c7a36 (patch)
treee531c88307514653e1fa5de03ec37fdf81bf3a6c
parent62eb320ab077890dbbcc28343fa6432a82a10c35 (diff)
downloadlinux-7eb391299419a03cbe0fa5ab0e6b0932e42c7a36.tar.xz
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. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--lib/vsprintf.c26
1 files changed, 13 insertions, 13 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 48ff9c36644d..f44e178e6ede 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1590,22 +1590,23 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
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
@@ -1615,8 +1616,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
* 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))