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authorTyler Hicks <tyhicks@canonical.com>2012-01-18 18:30:04 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-02-03 09:26:49 -0800
commitbd8f0a46a1d92470b88ae53e8282dc4edf4f0ba9 (patch)
tree2acc8fe9e620bea0e338965dddf700c3926542cc
parent7727d2c0b842a1971090a15c434b41049632fff5 (diff)
eCryptfs: Make truncate path killable
commit 5e6f0d769017cc49207ef56996e42363ec26c1f0 upstream. ecryptfs_write() handles the truncation of eCryptfs inodes. It grabs a page, zeroes out the appropriate portions, and then encrypts the page before writing it to the lower filesystem. It was unkillable and due to the lack of sparse file support could result in tying up a large portion of system resources, while encrypting pages of zeros, with no way for the truncate operation to be stopped from userspace. This patch adds the ability for ecryptfs_write() to detect a pending fatal signal and return as gracefully as possible. The intent is to leave the lower file in a useable state, while still allowing a user to break out of the encryption loop. If a pending fatal signal is detected, the eCryptfs inode size is updated to reflect the modified inode size and then -EINTR is returned. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ecryptfs/read_write.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 0cc4fafd6552..6b7854681c61 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -136,6 +136,11 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
size_t total_remaining_bytes = ((offset + size) - pos);
+ if (fatal_signal_pending(current)) {
+ rc = -EINTR;
+ break;
+ }
+
if (num_bytes > total_remaining_bytes)
num_bytes = total_remaining_bytes;
if (pos < offset) {
@@ -197,15 +202,19 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
}
pos += num_bytes;
}
- if ((offset + size) > ecryptfs_file_size) {
- i_size_write(ecryptfs_inode, (offset + size));
+ if (pos > ecryptfs_file_size) {
+ i_size_write(ecryptfs_inode, pos);
if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) {
- rc = ecryptfs_write_inode_size_to_metadata(
+ int rc2;
+
+ rc2 = ecryptfs_write_inode_size_to_metadata(
ecryptfs_inode);
- if (rc) {
+ if (rc2) {
printk(KERN_ERR "Problem with "
"ecryptfs_write_inode_size_to_metadata; "
- "rc = [%d]\n", rc);
+ "rc = [%d]\n", rc2);
+ if (!rc)
+ rc = rc2;
goto out;
}
}