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authorLinus Torvalds <torvalds@linux-foundation.org>2021-05-02 04:50:44 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-02 04:50:44 +0300
commit17ae69aba89dbfa2139b7f8024b757ab3cc42f59 (patch)
treed0d13c06cf9bb3024563036a9ba5213b06b454e0 /security/security.c
parente6f0bf09f0669b3c2cd77fa906830123279a0a21 (diff)
parent3532b0b4352ce79400b0aa68414f1a0fc422b920 (diff)
downloadlinux-17ae69aba89dbfa2139b7f8024b757ab3cc42f59.tar.xz
Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull Landlock LSM from James Morris: "Add Landlock, a new LSM from Mickaël Salaün. Briefly, Landlock provides for unprivileged application sandboxing. From Mickaël's cover letter: "The goal of Landlock is to enable to restrict ambient rights (e.g. global filesystem access) for a set of processes. Because Landlock is a stackable LSM [1], it makes possible to create safe security sandboxes as new security layers in addition to the existing system-wide access-controls. This kind of sandbox is expected to help mitigate the security impact of bugs or unexpected/malicious behaviors in user-space applications. Landlock empowers any process, including unprivileged ones, to securely restrict themselves. Landlock is inspired by seccomp-bpf but instead of filtering syscalls and their raw arguments, a Landlock rule can restrict the use of kernel objects like file hierarchies, according to the kernel semantic. Landlock also takes inspiration from other OS sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD Pledge/Unveil. In this current form, Landlock misses some access-control features. This enables to minimize this patch series and ease review. This series still addresses multiple use cases, especially with the combined use of seccomp-bpf: applications with built-in sandboxing, init systems, security sandbox tools and security-oriented APIs [2]" The cover letter and v34 posting is here: https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/ See also: https://landlock.io/ This code has had extensive design discussion and review over several years" Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1] Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2] * tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: landlock: Enable user space to infer supported features landlock: Add user and kernel documentation samples/landlock: Add a sandbox manager example selftests/landlock: Add user space tests landlock: Add syscall implementations arch: Wire up Landlock syscalls fs,security: Add sb_delete hook landlock: Support filesystem access-control LSM: Infrastructure management of the superblock landlock: Add ptrace restrictions landlock: Set up the security framework and manage credentials landlock: Add ruleset and domain management landlock: Add object management
Diffstat (limited to 'security/security.c')
-rw-r--r--security/security.c51
1 files changed, 44 insertions, 7 deletions
diff --git a/security/security.c b/security/security.c
index 94383f83ba42..b38155b2de83 100644
--- a/security/security.c
+++ b/security/security.c
@@ -203,6 +203,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc);
lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
+ lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock);
lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
}
@@ -333,12 +334,13 @@ static void __init ordered_lsm_init(void)
for (lsm = ordered_lsms; *lsm; lsm++)
prepare_lsm(*lsm);
- init_debug("cred blob size = %d\n", blob_sizes.lbs_cred);
- init_debug("file blob size = %d\n", blob_sizes.lbs_file);
- init_debug("inode blob size = %d\n", blob_sizes.lbs_inode);
- init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc);
- init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
- init_debug("task blob size = %d\n", blob_sizes.lbs_task);
+ init_debug("cred blob size = %d\n", blob_sizes.lbs_cred);
+ init_debug("file blob size = %d\n", blob_sizes.lbs_file);
+ init_debug("inode blob size = %d\n", blob_sizes.lbs_inode);
+ init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc);
+ init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
+ init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
+ init_debug("task blob size = %d\n", blob_sizes.lbs_task);
/*
* Create any kmem_caches needed for blobs
@@ -670,6 +672,27 @@ static void __init lsm_early_task(struct task_struct *task)
panic("%s: Early task alloc failed.\n", __func__);
}
+/**
+ * lsm_superblock_alloc - allocate a composite superblock blob
+ * @sb: the superblock that needs a blob
+ *
+ * Allocate the superblock blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_superblock_alloc(struct super_block *sb)
+{
+ if (blob_sizes.lbs_superblock == 0) {
+ sb->s_security = NULL;
+ return 0;
+ }
+
+ sb->s_security = kzalloc(blob_sizes.lbs_superblock, GFP_KERNEL);
+ if (sb->s_security == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
/*
* The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
* can be accessed with:
@@ -867,12 +890,26 @@ int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *
int security_sb_alloc(struct super_block *sb)
{
- return call_int_hook(sb_alloc_security, 0, sb);
+ int rc = lsm_superblock_alloc(sb);
+
+ if (unlikely(rc))
+ return rc;
+ rc = call_int_hook(sb_alloc_security, 0, sb);
+ if (unlikely(rc))
+ security_sb_free(sb);
+ return rc;
+}
+
+void security_sb_delete(struct super_block *sb)
+{
+ call_void_hook(sb_delete, sb);
}
void security_sb_free(struct super_block *sb)
{
call_void_hook(sb_free_security, sb);
+ kfree(sb->s_security);
+ sb->s_security = NULL;
}
void security_free_mnt_opts(void **mnt_opts)