80 lines
2.7 KiB
Diff
80 lines
2.7 KiB
Diff
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Thu, 13 Dec 2018 13:25:11 +0100
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Subject: usb-mtp: use O_NOFOLLOW and O_CLOEXEC.
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Open files and directories with O_NOFOLLOW to avoid symlinks attacks.
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While being at it also add O_CLOEXEC.
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usb-mtp only handles regular files and directories and ignores
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everything else, so users should not see a difference.
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Because qemu ignores symlinks, carrying out a successful symlink attack
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requires swapping an existing file or directory below rootdir for a
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symlink and winning the race against the inotify notification to qemu.
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Fixes: CVE-2018-16872
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Cc: Prasad J Pandit <ppandit@redhat.com>
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Cc: Bandan Das <bsd@redhat.com>
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Reported-by: Michael Hanselmann <public@hansmi.ch>
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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Reviewed-by: Michael Hanselmann <public@hansmi.ch>
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Message-id: 20181213122511.13853-1-kraxel@redhat.com
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(cherry picked from commit bab9df35ce73d1c8e19a37e2737717ea1c984dc1)
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[BR: BSC#1119493]
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Signed-off-by: Bruce Rogers <brogers@suse.com>
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---
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hw/usb/dev-mtp.c | 13 +++++++++----
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1 file changed, 9 insertions(+), 4 deletions(-)
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diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
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index 100b7171f4..36c43b8c20 100644
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--- a/hw/usb/dev-mtp.c
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+++ b/hw/usb/dev-mtp.c
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@@ -653,13 +653,18 @@ static void usb_mtp_object_readdir(MTPState *s, MTPObject *o)
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{
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struct dirent *entry;
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DIR *dir;
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+ int fd;
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if (o->have_children) {
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return;
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}
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o->have_children = true;
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- dir = opendir(o->path);
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+ fd = open(o->path, O_DIRECTORY | O_CLOEXEC | O_NOFOLLOW);
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+ if (fd < 0) {
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+ return;
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+ }
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+ dir = fdopendir(fd);
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if (!dir) {
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return;
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}
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@@ -1007,7 +1012,7 @@ static MTPData *usb_mtp_get_object(MTPState *s, MTPControl *c,
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trace_usb_mtp_op_get_object(s->dev.addr, o->handle, o->path);
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- d->fd = open(o->path, O_RDONLY);
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+ d->fd = open(o->path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
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if (d->fd == -1) {
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usb_mtp_data_free(d);
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return NULL;
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@@ -1031,7 +1036,7 @@ static MTPData *usb_mtp_get_partial_object(MTPState *s, MTPControl *c,
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c->argv[1], c->argv[2]);
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d = usb_mtp_data_alloc(c);
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- d->fd = open(o->path, O_RDONLY);
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+ d->fd = open(o->path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
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if (d->fd == -1) {
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usb_mtp_data_free(d);
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return NULL;
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@@ -1658,7 +1663,7 @@ static void usb_mtp_write_data(MTPState *s)
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0, 0, 0, 0);
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goto done;
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}
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- d->fd = open(path, O_CREAT | O_WRONLY, mask);
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+ d->fd = open(path, O_CREAT | O_WRONLY | O_CLOEXEC | O_NOFOLLOW, mask);
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if (d->fd == -1) {
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usb_mtp_queue_result(s, RES_STORE_FULL, d->trans,
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0, 0, 0, 0);
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