X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=Documentation%2Fsysctl%2Fkernel.txt;h=2a680896ee3610cd8ec905853cc82ddb936028e7;hp=1f2463671a1a4d59d0981f0b877c2a1246da82db;hb=373dcf178f11e09037edea51478f8340dcb583e3;hpb=c1f4246716392ec8693c23cffb969bd73c1b0910

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 1f2463671a1a..2a680896ee36 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -283,13 +283,24 @@ Default value is "/sbin/hotplug".
 kptr_restrict:
 
 This toggle indicates whether restrictions are placed on
-exposing kernel addresses via /proc and other interfaces.  When
-kptr_restrict is set to (0), there are no restrictions.  When
-kptr_restrict is set to (1), the default, kernel pointers
-printed using the %pK format specifier will be replaced with 0's
-unless the user has CAP_SYSLOG.  When kptr_restrict is set to
-(2), kernel pointers printed using %pK will be replaced with 0's
-regardless of privileges.
+exposing kernel addresses via /proc and other interfaces.
+
+When kptr_restrict is set to (0), the default, there are no restrictions.
+
+When kptr_restrict is set to (1), kernel pointers printed using the %pK
+format specifier will be replaced with 0's unless the user has CAP_SYSLOG
+and effective user and group ids are equal to the real ids. This is
+because %pK checks are done at read() time rather than open() time, so
+if permissions are elevated between the open() and the read() (e.g via
+a setuid binary) then %pK will not leak kernel pointers to unprivileged
+users. Note, this is a temporary solution only. The correct long-term
+solution is to do the permission checks at open() time. Consider removing
+world read permissions from files that use %pK, and using dmesg_restrict
+to protect against uses of %pK in dmesg(8) if leaking kernel pointer
+values to unprivileged users is a concern.
+
+When kptr_restrict is set to (2), kernel pointers printed using
+%pK will be replaced with 0's regardless of privileges.
 
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