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authorDan Rosenberg2010-11-11 16:05:18 -0600
committerLinus Torvalds2010-11-12 09:55:32 -0600
commiteaf06b241b091357e72b76863ba16e89610d31bd (patch)
tree83bc8667309050b3538630707513574c14c51f37 /security/Kconfig
parent203f40a5a030ed4048cd40e3bd9ab5df6c5df589 (diff)
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Restrict unprivileged access to kernel syslog
The kernel syslog contains debugging information that is often useful during exploitation of other vulnerabilities, such as kernel heap addresses. Rather than futilely attempt to sanitize hundreds (or thousands) of printk statements and simultaneously cripple useful debugging functionality, it is far simpler to create an option that prevents unprivileged users from reading the syslog. This patch, loosely based on grsecurity's GRKERNSEC_DMESG, creates the dmesg_restrict sysctl. When set to "0", the default, no restrictions are enforced. When set to "1", only users with CAP_SYS_ADMIN can read the kernel syslog via dmesg(8) or other mechanisms. [akpm@linux-foundation.org: explain the config option in kernel.txt] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Eugene Teo <eugeneteo@kernel.org> Acked-by: Kees Cook <kees.cook@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/Kconfig')
-rw-r--r--security/Kconfig12
1 files changed, 12 insertions, 0 deletions
diff --git a/security/Kconfig b/security/Kconfig
index bd72ae62349..e80da955e68 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -39,6 +39,18 @@ config KEYS_DEBUG_PROC_KEYS
39 39
40 If you are unsure as to whether this is required, answer N. 40 If you are unsure as to whether this is required, answer N.
41 41
42config SECURITY_DMESG_RESTRICT
43 bool "Restrict unprivileged access to the kernel syslog"
44 default n
45 help
46 This enforces restrictions on unprivileged users reading the kernel
47 syslog via dmesg(8).
48
49 If this option is not selected, no restrictions will be enforced
50 unless the dmesg_restrict sysctl is explicitly set to (1).
51
52 If you are unsure how to answer this question, answer N.
53
42config SECURITY 54config SECURITY
43 bool "Enable different security models" 55 bool "Enable different security models"
44 depends on SYSFS 56 depends on SYSFS