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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 09:14:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 09:14:50 -0800
commit299e2b1967578b1442128ba8b3e86ed3427d3651 (patch)
treebabd06008fd18541f5e39bffbe09fbfa0526b14d /security/apparmor
parente529d3507a93d3c9528580081bbaf931a50de154 (diff)
parentf6e53fb2d7bd70547ba53232415976cb70ad6d97 (diff)
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Merge tag 'landlock-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux
Pull landlock updates from Mickaël Salaün: "This adds file truncation support to Landlock, contributed by Günther Noack. As described by Günther [1], the goal of these patches is to work towards a more complete coverage of file system operations that are restrictable with Landlock. The known set of currently unsupported file system operations in Landlock is described at [2]. Out of the operations listed there, truncate is the only one that modifies file contents, so these patches should make it possible to prevent the direct modification of file contents with Landlock. The new LANDLOCK_ACCESS_FS_TRUNCATE access right covers both the truncate(2) and ftruncate(2) families of syscalls, as well as open(2) with the O_TRUNC flag. This includes usages of creat() in the case where existing regular files are overwritten. Additionally, this introduces a new Landlock security blob associated with opened files, to track the available Landlock access rights at the time of opening the file. This is in line with Unix's general approach of checking the read and write permissions during open(), and associating this previously checked authorization with the opened file. An ongoing patch documents this use case [3]. In order to treat truncate(2) and ftruncate(2) calls differently in an LSM hook, we split apart the existing security_path_truncate hook into security_path_truncate (for truncation by path) and security_file_truncate (for truncation of previously opened files)" Link: https://lore.kernel.org/r/20221018182216.301684-1-gnoack3000@gmail.com [1] Link: https://www.kernel.org/doc/html/v6.1/userspace-api/landlock.html#filesystem-flags [2] Link: https://lore.kernel.org/r/20221209193813.972012-1-mic@digikod.net [3] * tag 'landlock-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux: samples/landlock: Document best-effort approach for LANDLOCK_ACCESS_FS_REFER landlock: Document Landlock's file truncation support samples/landlock: Extend sample tool to support LANDLOCK_ACCESS_FS_TRUNCATE selftests/landlock: Test ftruncate on FDs created by memfd_create(2) selftests/landlock: Test FD passing from restricted to unrestricted processes selftests/landlock: Locally define __maybe_unused selftests/landlock: Test open() and ftruncate() in multiple scenarios selftests/landlock: Test file truncation support landlock: Support file truncation landlock: Document init_layer_masks() helper landlock: Refactor check_access_path_dual() into is_access_to_paths_allowed() security: Create file_truncate hook from path_truncate hook
Diffstat (limited to 'security/apparmor')
-rw-r--r--security/apparmor/lsm.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index f34675f7c3df..b751d6253977 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -333,6 +333,11 @@ static int apparmor_path_truncate(const struct path *path)
return common_perm_cond(OP_TRUNC, path, MAY_WRITE | AA_MAY_SETATTR);
}
+static int apparmor_file_truncate(struct file *file)
+{
+ return apparmor_path_truncate(&file->f_path);
+}
+
static int apparmor_path_symlink(const struct path *dir, struct dentry *dentry,
const char *old_name)
{
@@ -1241,6 +1246,7 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(mmap_file, apparmor_mmap_file),
LSM_HOOK_INIT(file_mprotect, apparmor_file_mprotect),
LSM_HOOK_INIT(file_lock, apparmor_file_lock),
+ LSM_HOOK_INIT(file_truncate, apparmor_file_truncate),
LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),