diff options
| author | Stephen Smalley <sds@tycho.nsa.gov> | 2020-01-08 11:24:47 -0500 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2020-02-10 10:49:01 -0500 |
| commit | e9c38f9fc2ccd31befe1bb1605b69213483a15b7 (patch) | |
| tree | 281e142f528909787ffc92dab94acfc0593d9474 /security/selinux | |
| parent | 4b36cb773a8153417a080f8025d522322f915aea (diff) | |
Documentation,selinux: deprecate setting checkreqprot to 1
Deprecate setting the SELinux checkreqprot tunable to 1 via kernel
parameter or /sys/fs/selinux/checkreqprot. Setting it to 0 is left
intact for compatibility since Android and some Linux distributions
do so for security and treat an inability to set it as a fatal error.
Eventually setting it to 0 will become a no-op and the kernel will
stop using checkreqprot's value internally altogether.
checkreqprot was originally introduced as a compatibility mechanism
for legacy userspace and the READ_IMPLIES_EXEC personality flag.
However, if set to 1, it weakens security by allowing mappings to be
made executable without authorization by policy. The default value
for the SECURITY_SELINUX_CHECKREQPROT_VALUE config option was changed
from 1 to 0 in commit 2a35d196c160e3 ("selinux: change
CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE default") and both Android
and Linux distributions began explicitly setting
/sys/fs/selinux/checkreqprot to 0 some time ago.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security/selinux')
| -rw-r--r-- | security/selinux/Kconfig | 3 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 5 | ||||
| -rw-r--r-- | security/selinux/selinuxfs.c | 8 |
3 files changed, 15 insertions, 1 deletions
diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig index 1014cb0ee956..9e921fc72538 100644 --- a/security/selinux/Kconfig +++ b/security/selinux/Kconfig @@ -88,6 +88,9 @@ config SECURITY_SELINUX_CHECKREQPROT_VALUE 'checkreqprot=' boot parameter. It may also be changed at runtime via /sys/fs/selinux/checkreqprot if authorized by policy. + WARNING: this option is deprecated and will be removed in a future + kernel release. + If you are unsure how to answer this question, answer 0. config SECURITY_SELINUX_SIDTAB_HASH_BITS diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index b33cf155cc48..d7762264f262 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -142,8 +142,11 @@ static int __init checkreqprot_setup(char *str) { unsigned long checkreqprot; - if (!kstrtoul(str, 0, &checkreqprot)) + if (!kstrtoul(str, 0, &checkreqprot)) { selinux_checkreqprot_boot = checkreqprot ? 1 : 0; + if (checkreqprot) + pr_warn("SELinux: checkreqprot set to 1 via kernel parameter. This is deprecated and will be rejected in a future kernel release.\n"); + } return 1; } __setup("checkreqprot=", checkreqprot_setup); diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 79c710911a3c..d6566adc73a6 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -668,6 +668,14 @@ static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf, if (sscanf(page, "%u", &new_value) != 1) goto out; + if (new_value) { + char comm[sizeof(current->comm)]; + + memcpy(comm, current->comm, sizeof(comm)); + pr_warn_once("SELinux: %s (%d) set checkreqprot to 1. This is deprecated and will be rejected in a future kernel release.\n", + comm, current->pid); + } + fsi->state->checkreqprot = new_value ? 1 : 0; length = count; out: |