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| author |   Ronnie Sahlberg <lsahlber@redhat.com> | 2017-09-28 09:39:58 +1000 |
|---|---|---|
| committer |   Steve French <smfrench@gmail.com> | 2017-10-18 11:52:39 -0500 |
| commit | 7cb3def44ce834e5ea462fd900505af4cd68b3d5 (patch) | |
| tree | 0dd9ce55764c6c44d2a851e63770cbe8ee0fc078 /fs/cifs/smb2ops.c | |
| parent | Fix encryption labels and lengths for SMB3.1.1 (diff) | |
| download | linux-dev-7cb3def44ce834e5ea462fd900505af4cd68b3d5.tar.xz linux-dev-7cb3def44ce834e5ea462fd900505af4cd68b3d5.zip | |
cifs: handle large EA requests more gracefully in smb2+
Update reading the EA using increasingly larger buffer sizes
until the response will fit in the buffer, or we exceed the
(arbitrary) maximum set to 64kb.
Without this change, a user is able to add more and more EAs using
setfattr until the point where the total space of all EAs exceed 2kb
at which point the user can no longer list the EAs at all
and getfattr will abort with an error.
The same issue still exists for EAs in SMB1.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/smb2ops.c')
| -rw-r--r-- | fs/cifs/smb2ops.c | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 0dafdbae1f8c..bdb963d0ba32 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -522,6 +522,7 @@ smb2_query_eas(const unsigned int xid, struct cifs_tcon *tcon, struct cifs_open_parms oparms; struct cifs_fid fid; struct smb2_file_full_ea_info *smb2_data; + int ea_buf_size = SMB2_MIN_EA_BUF; utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); if (!utf16_path) @@ -541,14 +542,32 @@ smb2_query_eas(const unsigned int xid, struct cifs_tcon *tcon, return rc; } - smb2_data = kzalloc(SMB2_MAX_EA_BUF, GFP_KERNEL); - if (smb2_data == NULL) { - SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid); - return -ENOMEM; + while (1) { + smb2_data = kzalloc(ea_buf_size, GFP_KERNEL); + if (smb2_data == NULL) { + SMB2_close(xid, tcon, fid.persistent_fid, + fid.volatile_fid); + return -ENOMEM; + } + + rc = SMB2_query_eas(xid, tcon, fid.persistent_fid, + fid.volatile_fid, + ea_buf_size, smb2_data); + + if (rc != -E2BIG) + break; + + kfree(smb2_data); + ea_buf_size <<= 1; + + if (ea_buf_size > SMB2_MAX_EA_BUF) { + cifs_dbg(VFS, "EA size is too large\n"); + SMB2_close(xid, tcon, fid.persistent_fid, + fid.volatile_fid); + return -ENOMEM; + } } - rc = SMB2_query_eas(xid, tcon, fid.persistent_fid, fid.volatile_fid, - smb2_data); SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid); if (!rc) |