Eric Lee / smarc-ti-linux-kernel

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Commit fee760fc6c79998efc48bd06afeec31824dfb2d4

Authored by Konstantin Khlebnikov
Committed by Greg Kroah-Hartman
1 parent 0fb615f9ca
Exists in smarct4x-processor-sdk-04.01.00.06 and in 1 other branch smarct3x-processor-sdk-04.01.00.06

ovl: drop CAP_SYS_RESOURCE from saved mounter's credentials 

commit 51f8f3c4e22535933ef9aecc00e9a6069e051b57 upstream.

If overlay was mounted by root then quota set for upper layer does not work
because overlay now always use mounter's credentials for operations.
Also overlay might deplete reserved space and inodes in ext4.

This patch drops capability SYS_RESOURCE from saved credentials.
This affects creation new files, whiteouts, and copy-up operations.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 1175b6b8d963 ("ovl: do operations on underlying file system in mounter's context")
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 6 additions and 2 deletions Side-by-side Diff

fs/overlayfs/super.c
Diff comments   View file @ fee760f
... ... @@ -1146,6 +1146,7 @@
1146 1146 unsigned int stacklen = 0;
1147 1147 unsigned int i;
1148 1148 bool remote = false;
  1149 + struct cred *cred;
1149 1150 int err;
1150 1151  
1151 1152 err = -ENOMEM;
1152 1153  
... ... @@ -1309,9 +1310,12 @@
1309 1310 else
1310 1311 sb->s_d_op = &ovl_dentry_operations;
1311 1312  
1312   - ufs->creator_cred = prepare_creds();
1313   - if (!ufs->creator_cred)
  1313 + ufs->creator_cred = cred = prepare_creds();
  1314 + if (!cred)
1314 1315 goto out_put_lower_mnt;
  1316 +
  1317 + /* Never override disk quota limits or use reserved space */
  1318 + cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
1315 1319  
1316 1320 err = -ENOMEM;
1317 1321 oe = ovl_alloc_entry(numlower);