diff options
Diffstat (limited to 'gnu/packages/patches/qemu-CVE-2017-7493.patch')
| -rw-r--r-- | gnu/packages/patches/qemu-CVE-2017-7493.patch | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/gnu/packages/patches/qemu-CVE-2017-7493.patch b/gnu/packages/patches/qemu-CVE-2017-7493.patch new file mode 100644 index 0000000000..67b26fad81 --- /dev/null +++ b/gnu/packages/patches/qemu-CVE-2017-7493.patch @@ -0,0 +1,182 @@ +Fix CVE-2017-7493: + +https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-7493 + +Patch copied from upstream source repository: + +http://git.qemu.org/?p=qemu.git;a=commit;h=7a95434e0ca8a037fd8aa1a2e2461f92585eb77b + +From 7a95434e0ca8a037fd8aa1a2e2461f92585eb77b Mon Sep 17 00:00:00 2001 +From: Greg Kurz <groug@kaod.org> +Date: Fri, 5 May 2017 14:48:08 +0200 +Subject: [PATCH] 9pfs: local: forbid client access to metadata (CVE-2017-7493) + +When using the mapped-file security mode, we shouldn't let the client mess +with the metadata. The current code already tries to hide the metadata dir +from the client by skipping it in local_readdir(). But the client can still +access or modify it through several other operations. This can be used to +escalate privileges in the guest. + +Affected backend operations are: +- local_mknod() +- local_mkdir() +- local_open2() +- local_symlink() +- local_link() +- local_unlinkat() +- local_renameat() +- local_rename() +- local_name_to_path() + +Other operations are safe because they are only passed a fid path, which +is computed internally in local_name_to_path(). + +This patch converts all the functions listed above to fail and return +EINVAL when being passed the name of the metadata dir. This may look +like a poor choice for errno, but there's no such thing as an illegal +path name on Linux and I could not think of anything better. + +This fixes CVE-2017-7493. + +Reported-by: Leo Gaspard <leo@gaspard.io> +Signed-off-by: Greg Kurz <groug@kaod.org> +Reviewed-by: Eric Blake <eblake@redhat.com> +--- + hw/9pfs/9p-local.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- + 1 file changed, 56 insertions(+), 2 deletions(-) + +diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c +index f3ebca4f7a..a2486566af 100644 +--- a/hw/9pfs/9p-local.c ++++ b/hw/9pfs/9p-local.c +@@ -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; +-- +2.13.0 + |