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[Qemu-devel] [PATCH RFC 32/36] 9pfs: local: lstat: don't follow symlinks
From: |
Greg Kurz |
Subject: |
[Qemu-devel] [PATCH RFC 32/36] 9pfs: local: lstat: don't follow symlinks |
Date: |
Mon, 30 Jan 2017 13:13:40 +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 | 36 ++++++++++++++++++++++++------------
1 file changed, 24 insertions(+), 12 deletions(-)
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 60edfb25f8a5..b46a81792ecf 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -168,12 +168,17 @@ static void local_mapped_file_attr(FsContext *ctx, const
char *path,
static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat
*stbuf)
{
- int err;
- char *buffer;
- char *path = fs_path->data;
+ int err = -1;
+ char *dirpath = local_dirname(fs_path->data);
+ char *name = local_basename(fs_path->data);
+ int dirfd;
- buffer = rpath(fs_ctx, path);
- err = lstat(buffer, stbuf);
+ dirfd = local_opendir_nofollow(fs_ctx, dirpath);
+ if (dirfd == -1) {
+ goto out;
+ }
+
+ err = fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW);
if (err) {
goto err_out;
}
@@ -183,25 +188,32 @@ static int local_lstat(FsContext *fs_ctx, V9fsPath
*fs_path, struct stat *stbuf)
gid_t tmp_gid;
mode_t tmp_mode;
dev_t tmp_dev;
- if (getxattr(buffer, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
+
+ if (fgetxattrat(dirfd, name, "user.virtfs.uid", &tmp_uid,
+ sizeof(uid_t)) > 0) {
stbuf->st_uid = le32_to_cpu(tmp_uid);
}
- if (getxattr(buffer, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
+ if (fgetxattrat(dirfd, name, "user.virtfs.gid", &tmp_gid,
+ sizeof(gid_t)) > 0) {
stbuf->st_gid = le32_to_cpu(tmp_gid);
}
- if (getxattr(buffer, "user.virtfs.mode",
- &tmp_mode, sizeof(mode_t)) > 0) {
+ if (fgetxattrat(dirfd, name, "user.virtfs.mode", &tmp_mode,
+ sizeof(mode_t)) > 0) {
stbuf->st_mode = le32_to_cpu(tmp_mode);
}
- if (getxattr(buffer, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0)
{
+ if (fgetxattrat(dirfd, name, "user.virtfs.rdev", &tmp_dev,
+ sizeof(dev_t)) > 0) {
stbuf->st_rdev = le64_to_cpu(tmp_dev);
}
} else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
- local_mapped_file_attr(fs_ctx, path, stbuf);
+ local_mapped_file_attr(fs_ctx, fs_path->data, stbuf);
}
err_out:
- g_free(buffer);
+ close_preserve_errno(dirfd);
+out:
+ g_free(name);
+ g_free(dirpath);
return err;
}
- [Qemu-devel] [PATCH RFC 21/36] 9pfs: local: truncate: don't follow symlinks, (continued)
- [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, 2017/01/30
- [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 <=
- [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