diff options
Diffstat (limited to '1505_XATTR_USER_PREFIX.patch')
-rw-r--r-- | 1505_XATTR_USER_PREFIX.patch | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/1505_XATTR_USER_PREFIX.patch b/1505_XATTR_USER_PREFIX.patch new file mode 100644 index 00000000..5d54c316 --- /dev/null +++ b/1505_XATTR_USER_PREFIX.patch @@ -0,0 +1,55 @@ +From: Anthony G. Basile <blueness@gentoo.org> + +This patch adds support for a restricted user-controlled namespace on +tmpfs filesystem used to house PaX flags. The namespace must be of the +form user.pax.* and its value cannot exceed a size of 8 bytes. + +This is needed even on all Gentoo systems so that XATTR_PAX flags +are preserved for users who might build packages using portage on +a tmpfs system with a non-hardened kernel and then switch to a +hardened kernel with XATTR_PAX enabled. + +The namespace is added to any user with Extended Attribute support +enabled for tmpfs. Users who do not enable xattrs will not have +the XATTR_PAX flags preserved. + +diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h +index e4629b9..6958086 100644 +--- a/include/linux/xattr.h ++++ b/include/linux/xattr.h +@@ -63,3 +63,8 @@ + #endif /* __KERNEL__ */ ++ ++/* User namespace */ ++#define XATTR_PAX_PREFIX XATTR_USER_PREFIX "pax." ++#define XATTR_PAX_FLAGS_SUFFIX "flags" ++#define XATTR_NAME_PAX_FLAGS XATTR_PAX_PREFIX XATTR_PAX_FLAGS_SUFFIX + + #endif /* _UAPI_LINUX_XATTR_H */ +diff --git a/mm/shmem.c b/mm/shmem.c +index 1c44af7..f23bb1b 100644 +--- a/mm/shmem.c ++++ b/mm/shmem.c +@@ -2201,6 +2201,7 @@ static const struct xattr_handler *shmem_xattr_handlers[] = { + static int shmem_xattr_validate(const char *name) + { + struct { const char *prefix; size_t len; } arr[] = { ++ { XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN}, + { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, + { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } + }; +@@ -2256,7 +2257,14 @@ static int shmem_setxattr(struct dentry *dentry, const char *name, + if (err) + return err; ++ ++ if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { ++ if (strcmp(name, XATTR_NAME_PAX_FLAGS)) ++ return -EOPNOTSUPP; ++ if (size > 8) ++ return -EINVAL; ++ } + + if (size == 0) + value = ""; /* empty EA, do not remove */ + + return shmem_xattr_set(dentry, name, value, size, flags); |