core_pattern: allow passing of arguments to user mode helper when core_pattern is a pipe

A rewrite of my previous post for this enhancement.  It uses jeremy's
split_argv/free_argv library functions to translate core_pattern into an argv
array to be passed to the user mode helper process.  It also adds a
translation to format_corename such that the origional value of RLIMIT_CORE
can be passed to userspace as an argument.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: <martin.pitt@ubuntu.com>
Cc: <wwoods@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 3 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 86c455447bc8..6450157062ea 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -29,6 +29,7 @@
 #include <linux/stat.h>
 #include <linux/fcntl.h>
 #include <linux/smp_lock.h>
+#include <linux/string.h>
 #include <linux/init.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
@@ -1514,6 +1515,14 @@ static int format_corename(char *corename, const char *pattern, long signr)
                                         goto out;
                                 out_ptr += rc;
                                 break;
+                        /* core limit size */
+                        case 'c':
+                                rc = snprintf(out_ptr, out_end - out_ptr,
+                                              "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
+                                if (rc > out_end - out_ptr)
+                                        goto out;
+                                out_ptr += rc;
+                                break;
                         default:
                                 break;
                         }
@@ -1698,6 +1707,9 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
         int flag = 0;
         int ispipe = 0;
         unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
+        char **helper_argv = NULL;
+        int helper_argc = 0;
+        char *delimit;
 
         audit_core_dumps(signr);
 
@@ -1746,14 +1758,18 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
          * at which point file size limits and permissions will be imposed
          * as it does with any other process
          */
-        if ((!ispipe) &&
-           (core_limit < binfmt->min_coredump))
+        if ((!ispipe) && (core_limit < binfmt->min_coredump))
                 goto fail_unlock;
 
         if (ispipe) {
                 core_limit = RLIM_INFINITY;
+                helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
+                /* Terminate the string before the first option */
+                delimit = strchr(corename, ' ');
+                if (delimit)
+                        *delimit = '\0';
                 /* SIGPIPE can happen, but it's just never processed */
-                if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
+                if(call_usermodehelper_pipe(corename+1, helper_argv, NULL, &file)) {
                         printk(KERN_INFO "Core dump to %s pipe failed\n",
                                corename);
                         goto fail_unlock;
@@ -1788,6 +1804,9 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
 close_fail:
         filp_close(file, NULL);
 fail_unlock:
+        if (helper_argv)
+                argv_free(helper_argv);
+
         current->fsuid = fsuid;
         complete_all(&mm->core_done);
 fail: