kernel: extend seccomp with a LOG action

Signed-off-by: John Crispin <blogic@openwrt.org>
SVN-Revision: 45007

diff --git a/target/linux/generic/patches-3.18/999-seccomp_log.patch b/target/linux/generic/patches-3.18/999-seccomp_log.patch
new file mode 100644 (file)
index 0000000..1f90b32
--- /dev/null
+++ b/target/linux/generic/patches-3.18/999-seccomp_log.patch
@@ -0,0 +1,34 @@
+--- a/kernel/seccomp.c
++++ b/kernel/seccomp.c
+@@ -614,6 +614,7 @@
+ #ifdef CONFIG_SECCOMP_FILTER
+ static u32 __seccomp_phase1_filter(int this_syscall, struct seccomp_data *sd)
+ {
++      char name[sizeof(current->comm)];
+       u32 filter_ret, action;
+       int data;
+ 
+@@ -644,6 +645,13 @@
+       case SECCOMP_RET_TRACE:
+               return filter_ret;  /* Save the rest for phase 2. */
+ 
++      case SECCOMP_RET_LOG:
++              get_task_comm(name, current);
++              pr_err_ratelimited("seccomp: %s [%u] tried to call non-whitelisted syscall: %d\n", name, current->pid, this_syscall);
++              syscall_set_return_value(current, task_pt_regs(current),
++                                       -data, 0);
++              goto skip;
++
+       case SECCOMP_RET_ALLOW:
+               return SECCOMP_PHASE1_OK;
+ 
+--- a/include/uapi/linux/seccomp.h
++++ b/include/uapi/linux/seccomp.h
+@@ -28,6 +28,7 @@
+ #define SECCOMP_RET_KILL      0x00000000U /* kill the task immediately */
+ #define SECCOMP_RET_TRAP      0x00030000U /* disallow and force a SIGSYS */
+ #define SECCOMP_RET_ERRNO     0x00050000U /* returns an errno */
++#define SECCOMP_RET_LOG               0x00070000U /* allow + logline */
+ #define SECCOMP_RET_TRACE     0x7ff00000U /* pass to a tracer or disallow */
+ #define SECCOMP_RET_ALLOW     0x7fff0000U /* allow */
+