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| author | Igor Mammedov <niallain@gmail.com> | 2009-04-21 19:31:05 +0400 |
|---|---|---|
| committer | Steve French <sfrench@us.ibm.com> | 2009-04-30 21:24:09 +0400 |
| commit | 5c2503a8e339fbc82f49d5706c5a4ad650dd9711 (patch) | |
| tree | 3b56e1e41b35ef743cc469b91f0aff184ec06898 | |
| parent | 1af28ceb923d04357733642a3dbc4497da4db1c2 (diff) | |
| download | linux-5c2503a8e339fbc82f49d5706c5a4ad650dd9711.tar.xz | |
Added loop check when mounting DFS tree.
Added loop check when mounting DFS tree. mount will fail with
ELOOP if referral walks exceed MAX_NESTED_LINK count.
Signed-off-by: Igor Mammedov <niallain@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
| -rw-r--r-- | fs/cifs/connect.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 579a628d1e65..7e5d4fda4936 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -32,6 +32,7 @@ #include <linux/kthread.h> #include <linux/pagevec.h> #include <linux/freezer.h> +#include <linux/namei.h> #include <asm/uaccess.h> #include <asm/processor.h> #include <net/ipv6.h> @@ -2278,6 +2279,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb, #ifdef CONFIG_CIFS_DFS_UPCALL struct dfs_info3_param *referrals = NULL; unsigned int num_referrals = 0; + int referral_walks_count = 0; try_mount_again: #endif full_path = NULL; @@ -2525,6 +2527,16 @@ remote_path_check: /* get referral if needed */ if (rc == -EREMOTE) { #ifdef CONFIG_CIFS_DFS_UPCALL + if (referral_walks_count > MAX_NESTED_LINKS) { + /* + * BB: when we implement proper loop detection, + * we will remove this check. But now we need it + * to prevent an indefinite loop if 'DFS tree' is + * misconfigured (i.e. has loops). + */ + rc = -ELOOP; + goto mount_fail_check; + } /* convert forward to back slashes in prepath here if needed */ if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) == 0) convert_delimiter(cifs_sb->prepath, @@ -2558,6 +2570,7 @@ remote_path_check: cleanup_volume_info(&volume_info); FreeXid(xid); kfree(full_path); + referral_walks_count++; goto try_mount_again; } #else /* No DFS support, return error on mount */ |