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authorAl Viro <viro@zeniv.linux.org.uk>2012-08-22 06:32:06 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-09-27 05:09:59 +0400
commitc3c073f808b22dfae15ef8412b6f7b998644139a (patch)
tree3369bcbe414738d90e6ccfe257f6ce3e72f6a5ae /security
parentad47bd7252bf402fe7dba92f5240b5ed16832ae7 (diff)
downloadlinux-c3c073f808b22dfae15ef8412b6f7b998644139a.tar.xz
new helper: iterate_fd()
iterates through the opened files in given descriptor table, calling a supplied function; we stop once non-zero is returned. Callback gets struct file *, descriptor number and const void * argument passed to iterator. It is called with files->file_lock held, so it is not allowed to block. tty_io, netprio_cgroup and selinux flush_unauthorized_files() converted to its use. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c57
1 files changed, 22 insertions, 35 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 00b50113642d..4dfbcea10eb7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2088,15 +2088,19 @@ static int selinux_bprm_secureexec(struct linux_binprm *bprm)
return (atsecure || cap_bprm_secureexec(bprm));
}
+static int match_file(const void *p, struct file *file, unsigned fd)
+{
+ return file_has_perm(p, file, file_to_av(file)) ? fd + 1 : 0;
+}
+
/* Derived from fs/exec.c:flush_old_files. */
static inline void flush_unauthorized_files(const struct cred *cred,
struct files_struct *files)
{
struct file *file, *devnull = NULL;
struct tty_struct *tty;
- struct fdtable *fdt;
- long j = -1;
int drop_tty = 0;
+ unsigned n;
tty = get_current_tty();
if (tty) {
@@ -2123,41 +2127,24 @@ static inline void flush_unauthorized_files(const struct cred *cred,
no_tty();
/* Revalidate access to inherited open files. */
- spin_lock(&files->file_lock);
- for (;;) {
- unsigned long set, i;
- j++;
- i = j * BITS_PER_LONG;
- fdt = files_fdtable(files);
- if (i >= fdt->max_fds)
- break;
- set = fdt->open_fds[j];
- if (!set)
- continue;
- spin_unlock(&files->file_lock);
- for ( ; set ; i++, set >>= 1) {
- if (!(set & 1))
- continue;
- file = fget(i);
- if (!file)
- continue;
- if (file_has_perm(cred, file, file_to_av(file))) {
- if (devnull) {
- get_file(devnull);
- } else {
- devnull = dentry_open(&selinux_null,
- O_RDWR, cred);
- if (IS_ERR(devnull))
- devnull = NULL;
- }
- replace_fd(i, devnull, 0);
- }
- fput(file);
- }
- spin_lock(&files->file_lock);
+ n = iterate_fd(files, 0, match_file, cred);
+ if (!n) /* none found? */
+ return;
+ devnull = dentry_open(&selinux_null, O_RDWR, cred);
+ if (!IS_ERR(devnull)) {
+ /* replace all the matching ones with this */
+ do {
+ get_file(devnull);
+ replace_fd(n - 1, devnull, 0);
+ } while ((n = iterate_fd(files, n, match_file, cred)) != 0);
+ fput(devnull);
+ } else {
+ /* just close all the matching ones */
+ do {
+ replace_fd(n - 1, NULL, 0);
+ } while ((n = iterate_fd(files, n, match_file, cred)) != 0);
}
- spin_unlock(&files->file_lock);
}
/*