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authorDenys Vlasenko <vda.linux@googlemail.com>2017-01-07 10:15:01 +0100
committerDenys Vlasenko <vda.linux@googlemail.com>2017-01-07 10:16:56 +0100
commit86584e134eec1a81298149f8c04c77727f6dccb9 (patch)
tree6e3323d82c8dc1c2c7da58fa86573ca1cea33e71
parentfe93624fb69e3858ebaea2d9e53e0522c1025698 (diff)
downloadbusybox-86584e134eec1a81298149f8c04c77727f6dccb9.tar.gz
ash: fix open fds leaking in redirects. Closes 9561
commit e19923f6652a638ac39c84012e97f52cf5a7568e deleted clearredir() call in shellexec(): ash: [REDIR] Remove redundant CLOEXEC calls Upstream commit: Now that we're marking file descriptors as CLOEXEC in savefd, we no longer need to close them on exec or in setinputfd. but it missed one place where we don't set CLOEXEC. Fixing this. Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--shell/ash.c11
-rw-r--r--shell/ash_test/ash-redir/redir_leak.right6
-rwxr-xr-xshell/ash_test/ash-redir/redir_leak.tests10
-rw-r--r--shell/hush_test/hush-redir/redir_leak.right6
-rwxr-xr-xshell/hush_test/hush-redir/redir_leak.tests10
5 files changed, 39 insertions, 4 deletions
diff --git a/shell/ash.c b/shell/ash.c
index aee3d419c..efb4615db 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5433,11 +5433,11 @@ redirect(union node *redir, int flags)
/* Careful to not accidentally "save"
* to the same fd as right side fd in N>&M */
int minfd = right_fd < 10 ? 10 : right_fd + 1;
+#if defined(F_DUPFD_CLOEXEC)
+ i = fcntl(fd, F_DUPFD_CLOEXEC, minfd);
+#else
i = fcntl(fd, F_DUPFD, minfd);
-/* You'd expect copy to be CLOEXECed. Currently these extra "saved" fds
- * are closed in popredir() in the child, preventing them from leaking
- * into child. (popredir() also cleans up the mess in case of failures)
- */
+#endif
if (i == -1) {
i = errno;
if (i != EBADF) {
@@ -5452,6 +5452,9 @@ redirect(union node *redir, int flags)
remember_to_close:
i = CLOSED;
} else { /* fd is open, save its copy */
+#if !defined(F_DUPFD_CLOEXEC)
+ fcntl(i, F_SETFD, FD_CLOEXEC);
+#endif
/* "exec fd>&-" should not close fds
* which point to script file(s).
* Force them to be restored afterwards */
diff --git a/shell/ash_test/ash-redir/redir_leak.right b/shell/ash_test/ash-redir/redir_leak.right
new file mode 100644
index 000000000..b1c48292b
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir_leak.right
@@ -0,0 +1,6 @@
+4
+4
+4
+4
+4
+4
diff --git a/shell/ash_test/ash-redir/redir_leak.tests b/shell/ash_test/ash-redir/redir_leak.tests
new file mode 100755
index 000000000..c8a9c6343
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir_leak.tests
@@ -0,0 +1,10 @@
+# Each of these should show only four lines:
+# fds 0,1,2 are stdio; fd 3 is open by opendir() in ls.
+# This test detects bugs where redirects leave stray open fds.
+
+ls -1 /proc/self/fd | wc -l
+ls -1 /proc/self/fd >/proc/self/fd/1 | wc -l
+ls -1 /proc/self/fd >/proc/self/fd/1 2>&1 | wc -l
+echo "`ls -1 /proc/self/fd `" | wc -l
+echo "`ls -1 /proc/self/fd >/proc/self/fd/1 `" | wc -l
+echo "`ls -1 /proc/self/fd >/proc/self/fd/1 2>&1 `" | wc -l
diff --git a/shell/hush_test/hush-redir/redir_leak.right b/shell/hush_test/hush-redir/redir_leak.right
new file mode 100644
index 000000000..b1c48292b
--- /dev/null
+++ b/shell/hush_test/hush-redir/redir_leak.right
@@ -0,0 +1,6 @@
+4
+4
+4
+4
+4
+4
diff --git a/shell/hush_test/hush-redir/redir_leak.tests b/shell/hush_test/hush-redir/redir_leak.tests
new file mode 100755
index 000000000..c8a9c6343
--- /dev/null
+++ b/shell/hush_test/hush-redir/redir_leak.tests
@@ -0,0 +1,10 @@
+# Each of these should show only four lines:
+# fds 0,1,2 are stdio; fd 3 is open by opendir() in ls.
+# This test detects bugs where redirects leave stray open fds.
+
+ls -1 /proc/self/fd | wc -l
+ls -1 /proc/self/fd >/proc/self/fd/1 | wc -l
+ls -1 /proc/self/fd >/proc/self/fd/1 2>&1 | wc -l
+echo "`ls -1 /proc/self/fd `" | wc -l
+echo "`ls -1 /proc/self/fd >/proc/self/fd/1 `" | wc -l
+echo "`ls -1 /proc/self/fd >/proc/self/fd/1 2>&1 `" | wc -l