diff options
Diffstat (limited to 'meta/recipes-core/systemd/systemd/CVE-2021-3997-3.patch')
-rw-r--r-- | meta/recipes-core/systemd/systemd/CVE-2021-3997-3.patch | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/meta/recipes-core/systemd/systemd/CVE-2021-3997-3.patch b/meta/recipes-core/systemd/systemd/CVE-2021-3997-3.patch new file mode 100644 index 0000000000..c96b8d9a6e --- /dev/null +++ b/meta/recipes-core/systemd/systemd/CVE-2021-3997-3.patch @@ -0,0 +1,266 @@ +Backport of the following upstream commit: +From bef8e8e577368697b2e6f85183b1dbc99e0e520f Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl> +Date: Tue, 30 Nov 2021 22:29:05 +0100 +Subject: [PATCH 3/3] shared/rm-rf: loop over nested directories instead of + instead of recursing + +To remove directory structures, we need to remove the innermost items first, +and then recursively remove higher-level directories. We would recursively +descend into directories and invoke rm_rf_children and rm_rm_children_inner. +This is problematic when too many directories are nested. + +Instead, let's create a "TODO" queue. In the the queue, for each level we +hold the DIR* object we were working on, and the name of the directory. This +allows us to leave a partially-processed directory, and restart the removal +loop one level down. When done with the inner directory, we use the name to +unlinkat() it from the parent, and proceed with the removal of other items. + +Because the nesting is increased by one level, it is best to view this patch +with -b/--ignore-space-change. + +This fixes CVE-2021-3997, https://bugzilla.redhat.com/show_bug.cgi?id=2024639. +The issue was reported and patches reviewed by Qualys Team. +Mauro Matteo Cascella and Riccardo Schirone from Red Hat handled the disclosure. + +CVE: CVE-2021-3997 +Upstream-Status: Backport [http://archive.ubuntu.com/ubuntu/pool/main/s/systemd/systemd_245.4-4ubuntu3.15.debian.tar.xz] +Signed-off-by: Purushottam Choudhary <Purushottam.Choudhary@kpit.com> +--- + src/basic/rm-rf.c | 161 +++++++++++++++++++++++++++++++-------------- + 1 file changed, 113 insertions(+), 48 deletions(-) + +--- a/src/basic/rm-rf.c ++++ b/src/basic/rm-rf.c +@@ -26,12 +26,13 @@ + return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs); + } + +-static int rm_rf_children_inner( ++static int rm_rf_inner_child( + int fd, + const char *fname, + int is_dir, + RemoveFlags flags, +- const struct stat *root_dev) { ++ const struct stat *root_dev, ++ bool allow_recursion) { + + struct stat st; + int r, q = 0; +@@ -49,9 +50,7 @@ + } + + if (is_dir) { +- _cleanup_close_ int subdir_fd = -1; +- +- /* if root_dev is set, remove subdirectories only if device is same */ ++ /* If root_dev is set, remove subdirectories only if device is same */ + if (root_dev && st.st_dev != root_dev->st_dev) + return 0; + +@@ -63,7 +62,6 @@ + return 0; + + if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) { +- + /* This could be a subvolume, try to remove it */ + + r = btrfs_subvol_remove_fd(fd, fname, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA); +@@ -77,13 +75,16 @@ + return 1; + } + +- subdir_fd = openat(fd, fname, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); ++ if (!allow_recursion) ++ return -EISDIR; ++ ++ int subdir_fd = openat(fd, fname, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); + if (subdir_fd < 0) + return -errno; + + /* We pass REMOVE_PHYSICAL here, to avoid doing the fstatfs() to check the file system type + * again for each directory */ +- q = rm_rf_children(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev); ++ q = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev); + + } else if (flags & REMOVE_ONLY_DIRECTORIES) + return 0; +@@ -96,64 +97,128 @@ + return 1; + } + ++typedef struct TodoEntry { ++ DIR *dir; /* A directory that we were operating on. */ ++ char *dirname; /* The filename of that directory itself. */ ++} TodoEntry; ++ ++static void free_todo_entries(TodoEntry **todos) { ++ for (TodoEntry *x = *todos; x && x->dir; x++) { ++ closedir(x->dir); ++ free(x->dirname); ++ } ++ ++ freep(todos); ++} ++ + int rm_rf_children( + int fd, + RemoveFlags flags, + const struct stat *root_dev) { + +- _cleanup_closedir_ DIR *d = NULL; +- struct dirent *de; ++ _cleanup_(free_todo_entries) TodoEntry *todos = NULL; ++ size_t n_todo = 0, allocated = 0; ++ _cleanup_free_ char *dirname = NULL; /* Set when we are recursing and want to delete ourselves */ + int ret = 0, r; + +- assert(fd >= 0); ++ /* Return the first error we run into, but nevertheless try to go on. ++ * The passed fd is closed in all cases, including on failure. */ + +- /* This returns the first error we run into, but nevertheless tries to go on. This closes the passed +- * fd, in all cases, including on failure. */ ++ for (;;) { /* This loop corresponds to the directory nesting level. */ ++ _cleanup_closedir_ DIR *d = NULL; ++ struct dirent *de; ++ ++ if (n_todo > 0) { ++ /* We know that we are in recursion here, because n_todo is set. ++ * We need to remove the inner directory we were operating on. */ ++ assert(dirname); ++ r = unlinkat(dirfd(todos[n_todo-1].dir), dirname, AT_REMOVEDIR); ++ if (r < 0 && r != -ENOENT && ret == 0) ++ ret = r; ++ dirname = mfree(dirname); ++ ++ /* And now let's back out one level up */ ++ n_todo --; ++ d = TAKE_PTR(todos[n_todo].dir); ++ dirname = TAKE_PTR(todos[n_todo].dirname); ++ ++ assert(d); ++ fd = dirfd(d); /* Retrieve the file descriptor from the DIR object */ ++ assert(fd >= 0); ++ } else { ++ next_fd: ++ assert(fd >= 0); ++ d = fdopendir(fd); ++ if (!d) { ++ safe_close(fd); ++ return -errno; ++ } ++ fd = dirfd(d); /* We donated the fd to fdopendir(). Let's make sure we sure we have ++ * the right descriptor even if it were to internally invalidate the ++ * one we passed. */ ++ ++ if (!(flags & REMOVE_PHYSICAL)) { ++ struct statfs sfs; ++ ++ if (fstatfs(fd, &sfs) < 0) ++ return -errno; ++ ++ if (is_physical_fs(&sfs)) { ++ /* We refuse to clean physical file systems with this call, unless ++ * explicitly requested. This is extra paranoia just to be sure we ++ * never ever remove non-state data. */ ++ ++ _cleanup_free_ char *path = NULL; ++ ++ (void) fd_get_path(fd, &path); ++ return log_error_errno(SYNTHETIC_ERRNO(EPERM), ++ "Attempted to remove disk file system under \"%s\", and we can't allow that.", ++ strna(path)); ++ } ++ } ++ } + +- d = fdopendir(fd); +- if (!d) { +- safe_close(fd); +- return -errno; +- } ++ FOREACH_DIRENT_ALL(de, d, return -errno) { ++ int is_dir; + +- if (!(flags & REMOVE_PHYSICAL)) { +- struct statfs sfs; ++ if (dot_or_dot_dot(de->d_name)) ++ continue; + +- if (fstatfs(dirfd(d), &sfs) < 0) +- return -errno; +- } ++ is_dir = de->d_type == DT_UNKNOWN ? -1 : de->d_type == DT_DIR; + +- if (is_physical_fs(&sfs)) { +- /* We refuse to clean physical file systems with this call, unless explicitly +- * requested. This is extra paranoia just to be sure we never ever remove non-state +- * data. */ +- +- _cleanup_free_ char *path = NULL; +- +- (void) fd_get_path(fd, &path); +- return log_error_errno(SYNTHETIC_ERRNO(EPERM), +- "Attempted to remove disk file system under \"%s\", and we can't allow that.", +- strna(path)); +- } +- } ++ r = rm_rf_inner_child(fd, de->d_name, is_dir, flags, root_dev, false); ++ if (r == -EISDIR) { ++ /* Push the current working state onto the todo list */ + +- FOREACH_DIRENT_ALL(de, d, return -errno) { +- int is_dir; ++ if (!GREEDY_REALLOC0(todos, allocated, n_todo + 2)) ++ return log_oom(); + +- if (dot_or_dot_dot(de->d_name)) +- continue; ++ _cleanup_free_ char *newdirname = strdup(de->d_name); ++ if (!newdirname) ++ return log_oom(); + +- is_dir = +- de->d_type == DT_UNKNOWN ? -1 : +- de->d_type == DT_DIR; +- +- r = rm_rf_children_inner(dirfd(d), de->d_name, is_dir, flags, root_dev); +- if (r < 0 && r != -ENOENT && ret == 0) +- ret = r; +- } ++ int newfd = openat(fd, de->d_name, ++ O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); ++ if (newfd >= 0) { ++ todos[n_todo++] = (TodoEntry) { TAKE_PTR(d), TAKE_PTR(dirname) }; ++ fd = newfd; ++ dirname = TAKE_PTR(newdirname); ++ ++ goto next_fd; + +- if (FLAGS_SET(flags, REMOVE_SYNCFS) && syncfs(dirfd(d)) < 0 && ret >= 0) +- ret = -errno; ++ } else if (errno != -ENOENT && ret == 0) ++ ret = -errno; ++ ++ } else if (r < 0 && r != -ENOENT && ret == 0) ++ ret = r; ++ } ++ ++ if (FLAGS_SET(flags, REMOVE_SYNCFS) && syncfs(fd) < 0 && ret >= 0) ++ ret = -errno; ++ ++ if (n_todo == 0) ++ break; ++ } + + return ret; + } +@@ -250,5 +315,5 @@ + if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME)) + return -EINVAL; + +- return rm_rf_children_inner(fd, name, -1, flags, NULL); ++ return rm_rf_inner_child(fd, name, -1, flags, NULL, true); + } |