Fix for CVE-2017-7493.

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Merge remote-tracking branch 'gkurz/tags/security-fix-for-2.10' into staging

Fix for CVE-2017-7493.

# gpg: Signature made Mon 15 May 2017 07:48:20 PM BST
# gpg:                using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg:                 aka "Greg Kurz <groug@free.fr>"
# gpg:                 aka "Greg Kurz <gkurz@fr.ibm.com>"
# gpg:                 aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg:                 aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg:                 aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg:                 aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894  DBA2 02FC 3AEB 0101 DBC2

* gkurz/tags/security-fix-for-2.10:
  9pfs: local: forbid client access to metadata (CVE-2017-7493)

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2017-05-16 15:26:24 +01:00
commit 96cd599818

View file

@ -452,6 +452,11 @@ static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
return telldir(fs->dir.stream);
}
static bool local_is_mapped_file_metadata(FsContext *fs_ctx, const char *name)
{
return !strcmp(name, VIRTFS_META_DIR);
}
static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs)
{
struct dirent *entry;
@ -465,8 +470,8 @@ again:
if (ctx->export_flags & V9FS_SM_MAPPED) {
entry->d_type = DT_UNKNOWN;
} else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
if (!strcmp(entry->d_name, VIRTFS_META_DIR)) {
/* skp the meta data directory */
if (local_is_mapped_file_metadata(ctx, entry->d_name)) {
/* skip the meta data directory */
goto again;
}
entry->d_type = DT_UNKNOWN;
@ -559,6 +564,12 @@ static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
int err = -1;
int dirfd;
if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(fs_ctx, name)) {
errno = EINVAL;
return -1;
}
dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
if (dirfd == -1) {
return -1;
@ -605,6 +616,12 @@ static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
int err = -1;
int dirfd;
if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(fs_ctx, name)) {
errno = EINVAL;
return -1;
}
dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
if (dirfd == -1) {
return -1;
@ -694,6 +711,12 @@ static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
int err = -1;
int dirfd;
if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(fs_ctx, name)) {
errno = EINVAL;
return -1;
}
/*
* Mark all the open to not follow symlinks
*/
@ -752,6 +775,12 @@ static int local_symlink(FsContext *fs_ctx, const char *oldpath,
int err = -1;
int dirfd;
if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(fs_ctx, name)) {
errno = EINVAL;
return -1;
}
dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
if (dirfd == -1) {
return -1;
@ -826,6 +855,12 @@ static int local_link(FsContext *ctx, V9fsPath *oldpath,
int ret = -1;
int odirfd, ndirfd;
if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(ctx, name)) {
errno = EINVAL;
return -1;
}
odirfd = local_opendir_nofollow(ctx, odirpath);
if (odirfd == -1) {
goto out;
@ -1096,6 +1131,12 @@ static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
const char *name, V9fsPath *target)
{
if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(ctx, name)) {
errno = EINVAL;
return -1;
}
if (dir_path) {
v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
} else if (strcmp(name, "/")) {
@ -1116,6 +1157,13 @@ static int local_renameat(FsContext *ctx, V9fsPath *olddir,
int ret;
int odirfd, ndirfd;
if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
(local_is_mapped_file_metadata(ctx, old_name) ||
local_is_mapped_file_metadata(ctx, new_name))) {
errno = EINVAL;
return -1;
}
odirfd = local_opendir_nofollow(ctx, olddir->data);
if (odirfd == -1) {
return -1;
@ -1206,6 +1254,12 @@ static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
int ret;
int dirfd;
if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
local_is_mapped_file_metadata(ctx, name)) {
errno = EINVAL;
return -1;
}
dirfd = local_opendir_nofollow(ctx, dir->data);
if (dirfd == -1) {
return -1;