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[Qemu-devel] [PATCH RFC 28/36] 9pfs: local: rename: don't follow symlink
From: |
Greg Kurz |
Subject: |
[Qemu-devel] [PATCH RFC 28/36] 9pfs: local: rename: don't follow symlinks |
Date: |
Mon, 30 Jan 2017 13:13:11 +0100 |
User-agent: |
StGit/0.17.1-20-gc0b1b-dirty |
This fixes CVE-2016-9602 for the "passthrough" and "mapped" security models.
Signed-off-by: Greg Kurz <address@hidden>
---
hw/9pfs/9p-local.c | 44 +++++++++++++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 13 deletions(-)
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index de860db3d70b..364da435350b 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -84,6 +84,14 @@ static void unlinkat_preserve_errno(int dirfd, const char
*path, int flags)
errno = serrno;
}
+static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd,
+ const char *npath)
+{
+ int serrno = errno;
+ renameat(odirfd, opath, ndirfd, npath);
+ errno = serrno;
+}
+
#define VIRTFS_META_DIR ".virtfs_metadata"
static char *local_mapped_attr_path(FsContext *ctx, const char *path)
@@ -1259,16 +1267,22 @@ static int local_post_rename_mapped_file(FsContext
*ctx, const char *oldpath,
static int local_rename(FsContext *ctx, const char *oldpath,
const char *newpath)
{
- int err;
- char *buffer, *buffer1;
- int serrno;
+ char *odirpath = local_dirname(oldpath);
+ char *oname = local_basename(oldpath);
+ char *ndirpath = local_dirname(newpath);
+ char *nname = local_basename(newpath);
+ int err = -1;
+ int odirfd, ndirfd;
- buffer = rpath(ctx, oldpath);
- buffer1 = rpath(ctx, newpath);
- err = rename(buffer, buffer1);
- if (err < 0) {
+ odirfd = local_opendir_nofollow(ctx, odirpath);
+ if (odirfd == -1) {
goto out;
}
+ ndirfd = local_opendir_nofollow(ctx, ndirpath);
+ if (ndirfd < 0) {
+ goto out_close_odirfd;
+ }
+ err = renameat(odirfd, oname, ndirfd, nname);
if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
err = local_post_rename_mapped_file(ctx, oldpath, newpath);
@@ -1276,15 +1290,19 @@ static int local_rename(FsContext *ctx, const char
*oldpath,
goto err_out;
}
}
- goto out;
+ goto out_close_ndirfd;
err_out:
- serrno = errno;
- rename(buffer1, buffer);
- errno = serrno;
+ renameat_preserve_errno(ndirfd, nname, odirfd, oname);
+out_close_ndirfd:
+ close_preserve_errno(ndirfd);
+out_close_odirfd:
+ close_preserve_errno(odirfd);
out:
- g_free(buffer);
- g_free(buffer1);
+ g_free(nname);
+ g_free(ndirpath);
+ g_free(oname);
+ g_free(odirpath);
return err;
}
- [Qemu-devel] [PATCH RFC 18/36] 9pfs: local: open/opendir: don't follow symlinks, (continued)
- [Qemu-devel] [PATCH RFC 18/36] 9pfs: local: open/opendir: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 19/36] 9pfs: local: utimensat: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 20/36] 9pfs: local: readlink: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 21/36] 9pfs: local: truncate: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 22/36] 9pfs: local: statfs: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 23/36] 9pfs: local: mknod/mkdir/open2: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 24/36] 9pfs: local: chmod: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 25/36] 9pfs: local: symlink: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 26/36] 9pfs: local: chown: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 27/36] 9pfs: local: link: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 28/36] 9pfs: local: rename: don't follow symlinks,
Greg Kurz <=
- [Qemu-devel] [PATCH RFC 29/36] 9pfs: local: remove: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 30/36] 9pfs: local: unlinkat: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 32/36] 9pfs: local: lstat: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 33/36] 9pfs: local: lgetxattr: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 35/36] 9pfs: local: lsetxattr: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 36/36] 9pfs: local: lremovexattr: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 34/36] 9pfs: local: llistxattr: don't follow symlinks, Greg Kurz, 2017/01/30
- [Qemu-devel] [PATCH RFC 31/36] 9pfs: local: introduce symlink-attack safe xattr helpers, Greg Kurz, 2017/01/30