[PATCH v1 3/3] security: define a trusted_for hook
From: Mimi Zohar <zohar@linux.ibm.com>
Date: 2021-10-14 13:01:49
Also in:
linux-security-module, lkml
Subsystem:
filesystems (vfs and infrastructure), security subsystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
Extend the trusted_for syscall to call the security_trusted_for hook, which calls registered LSMs and IMA, instead of calling IMA directly. Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> --- Mickaël, Casey, assuming there is a need... fs/open.c | 2 +- include/linux/lsm_hook_defs.h | 3 +++ include/linux/lsm_hooks.h | 6 ++++++ include/linux/security.h | 12 ++++++++++++ security/security.c | 10 ++++++++++ 5 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/fs/open.c b/fs/open.c
index 4d54e2a727e1..75336ca7020d 100644
--- a/fs/open.c
+++ b/fs/open.c@@ -586,7 +586,7 @@ SYSCALL_DEFINE3(trusted_for, const int, fd, const enum trusted_for_usage, usage, mask | MAY_ACCESS); if (!err) - err = ima_trusted_for(f.file, usage); + err = security_trusted_for(f.file, usage); out_fd: fdput(f);
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 2adeea44c0d5..f847fc0fd030 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h@@ -402,3 +402,6 @@ LSM_HOOK(void, LSM_RET_VOID, perf_event_free, struct perf_event *event) LSM_HOOK(int, 0, perf_event_read, struct perf_event *event) LSM_HOOK(int, 0, perf_event_write, struct perf_event *event) #endif /* CONFIG_PERF_EVENTS */ + +LSM_HOOK(int, 0, trusted_for, struct file *file, + const enum trusted_for_usage usage)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 5c4c5c0602cb..88e4f08f01ca 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h@@ -1557,6 +1557,12 @@ * Read perf_event security info if allowed. * @perf_event_write: * Write perf_event security info if allowed. + * + * Security hooks for trusted applications (e.g. interpreters) + * + * @trusted_for: + * Return kernel file integrity status to trusted application + * */ union security_list_options { #define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__);
diff --git a/include/linux/security.h b/include/linux/security.h
index 5b7288521300..b067e22c8903 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h@@ -31,6 +31,7 @@ #include <linux/err.h> #include <linux/string.h> #include <linux/mm.h> +#include <uapi/linux/trusted-for.h> struct linux_binprm; struct cred;
@@ -2038,4 +2039,15 @@ static inline int security_perf_event_write(struct perf_event *event) #endif /* CONFIG_SECURITY */ #endif /* CONFIG_PERF_EVENTS */ +#ifdef CONFIG_SECURITY +extern int security_trusted_for(struct file *file, + const enum trusted_for_usage usage); +#else +static int security_trusted_for(struct file *file, + const enum trusted_for_usage usage) +{ + return 0; +} +#endif /* CONFIG_SECURITY */ + #endif /* ! __LINUX_SECURITY_H */
diff --git a/security/security.c b/security/security.c
index 9ffa9e9c5c55..f8e2a131d5cd 100644
--- a/security/security.c
+++ b/security/security.c@@ -2625,3 +2625,13 @@ int security_perf_event_write(struct perf_event *event) return call_int_hook(perf_event_write, 0, event); } #endif /* CONFIG_PERF_EVENTS */ + +int security_trusted_for(struct file *file, const enum trusted_for_usage usage) +{ + int ret; + + ret = call_int_hook(trusted_for, 0, file, usage); + if (ret) + return ret; + return ima_trusted_for(file, usage); +}
--
2.27.0