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authorLuís Henriques <lhenriques@suse.de>2022-06-03 14:29:09 +0100
committerIlya Dryomov <idryomov@gmail.com>2022-08-03 00:54:12 +0200
commitd93231a6bc8a452323d5fef16cca7107ce483a27 (patch)
tree439f6d9295ccfee1165b0c5c9d9d8de01b65a724 /fs/ceph
parent8266c4d7a7469c3fd45ee2b4ebc01aac311c6c48 (diff)
ceph: prevent a client from exceeding the MDS maximum xattr size
The MDS tries to enforce a limit on the total key/values in extended attributes. However, this limit is enforced only if doing a synchronous operation (MDS_OP_SETXATTR) -- if we're buffering the xattrs, the MDS doesn't have a chance to enforce these limits. This patch adds support for decoding the xattrs maximum size setting that is distributed in the mdsmap. Then, when setting an xattr, the kernel client will revert to do a synchronous operation if that maximum size is exceeded. While there, fix a dout() that would trigger a printk warning: [ 98.718078] ------------[ cut here ]------------ [ 98.719012] precision 65536 too large [ 98.719039] WARNING: CPU: 1 PID: 3755 at lib/vsprintf.c:2703 vsnprintf+0x5e3/0x600 ... Link: https://tracker.ceph.com/issues/55725 Signed-off-by: Luís Henriques <lhenriques@suse.de> Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/mdsmap.c22
-rw-r--r--fs/ceph/xattr.c12
2 files changed, 26 insertions, 8 deletions
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
index 30387733765d..8d0a6d2c2da4 100644
--- a/fs/ceph/mdsmap.c
+++ b/fs/ceph/mdsmap.c
@@ -352,12 +352,10 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end, bool msgr2)
__decode_and_drop_type(p, end, u8, bad_ext);
}
if (mdsmap_ev >= 8) {
- u32 name_len;
/* enabled */
ceph_decode_8_safe(p, end, m->m_enabled, bad_ext);
- ceph_decode_32_safe(p, end, name_len, bad_ext);
- ceph_decode_need(p, end, name_len, bad_ext);
- *p += name_len;
+ /* fs_name */
+ ceph_decode_skip_string(p, end, bad_ext);
}
/* damaged */
if (mdsmap_ev >= 9) {
@@ -370,6 +368,22 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end, bool msgr2)
} else {
m->m_damaged = false;
}
+ if (mdsmap_ev >= 17) {
+ /* balancer */
+ ceph_decode_skip_string(p, end, bad_ext);
+ /* standby_count_wanted */
+ ceph_decode_skip_32(p, end, bad_ext);
+ /* old_max_mds */
+ ceph_decode_skip_32(p, end, bad_ext);
+ /* min_compat_client */
+ ceph_decode_skip_8(p, end, bad_ext);
+ /* required_client_features */
+ ceph_decode_skip_set(p, end, 64, bad_ext);
+ ceph_decode_64_safe(p, end, m->m_max_xattr_size, bad_ext);
+ } else {
+ /* This forces the usage of the (sync) SETXATTR Op */
+ m->m_max_xattr_size = 0;
+ }
bad_ext:
dout("mdsmap_decode m_enabled: %d, m_damaged: %d, m_num_laggy: %d\n",
!!m->m_enabled, !!m->m_damaged, m->m_num_laggy);
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index f141f5246163..f31350cda960 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1086,7 +1086,7 @@ static int ceph_sync_setxattr(struct inode *inode, const char *name,
flags |= CEPH_XATTR_REMOVE;
}
- dout("setxattr value=%.*s\n", (int)size, value);
+ dout("setxattr value size: %zu\n", size);
/* do request */
req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
@@ -1184,8 +1184,14 @@ int __ceph_setxattr(struct inode *inode, const char *name,
spin_lock(&ci->i_ceph_lock);
retry:
issued = __ceph_caps_issued(ci, NULL);
- if (ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))
+ required_blob_size = __get_required_blob_size(ci, name_len, val_len);
+ if ((ci->i_xattrs.version == 0) || !(issued & CEPH_CAP_XATTR_EXCL) ||
+ (required_blob_size > mdsc->mdsmap->m_max_xattr_size)) {
+ dout("%s do sync setxattr: version: %llu size: %d max: %llu\n",
+ __func__, ci->i_xattrs.version, required_blob_size,
+ mdsc->mdsmap->m_max_xattr_size);
goto do_sync;
+ }
if (!lock_snap_rwsem && !ci->i_head_snapc) {
lock_snap_rwsem = true;
@@ -1201,8 +1207,6 @@ retry:
ceph_cap_string(issued));
__build_xattrs(inode);
- required_blob_size = __get_required_blob_size(ci, name_len, val_len);
-
if (!ci->i_xattrs.prealloc_blob ||
required_blob_size > ci->i_xattrs.prealloc_blob->alloc_len) {
struct ceph_buffer *blob;