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ext4: clean up ext4_xattr_inode_get() 

The input and output values of *size parameter are equal on successful
return from ext4_xattr_inode_get().  On error return, the callers ignore
the output value so there is no need to update it.

Also check for NULL return from ext4_bread().  If the actual xattr inode
size happens to be smaller than the expected size, ext4_bread() may
return NULL which would indicate data corruption.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Tahsin Erdogan 2017-06-21 21:57:36 -04:00 committed by Theodore Ts'o
parent bab79b0499
commit 9096669332
1 changed files with 13 additions and 22 deletions
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35
fs/ext4/xattr.c
View File

@ -278,37 +278,28 @@ ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
/*
* Read the EA value from an inode.
*/
static int
ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t *size)
static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
{
unsigned long block = 0;
struct buffer_head *bh = NULL;
int blocksize;
size_t csize, ret_size = 0;
int blocksize = ea_inode->i_sb->s_blocksize;
size_t csize, copied = 0;
if (*size == 0)
return 0;
blocksize = ea_inode->i_sb->s_blocksize;
while (ret_size < *size) {
csize = (*size - ret_size) > blocksize ? blocksize :
*size - ret_size;
while (copied < size) {
csize = (size - copied) > blocksize ? blocksize : size - copied;
bh = ext4_bread(NULL, ea_inode, block, 0);
if (IS_ERR(bh)) {
*size = ret_size;
if (IS_ERR(bh))
return PTR_ERR(bh);
}
if (!bh)
return -EFSCORRUPTED;
memcpy(buf, bh->b_data, csize);
brelse(bh);
buf += csize;
block += 1;
ret_size += csize;
copied += csize;
}
*size = ret_size;
return 0;
}
@ -360,7 +351,7 @@ error:
*/
static int
ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
size_t *size)
size_t size)
{
struct inode *ea_inode;
int ret;
@ -417,7 +408,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
if (entry->e_value_inum) {
error = ext4_xattr_inode_get(inode,
le32_to_cpu(entry->e_value_inum),
buffer, &size);
buffer, size);
if (error)
goto cleanup;
} else {
@ -467,7 +458,7 @@ ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
if (entry->e_value_inum) {
error = ext4_xattr_inode_get(inode,
le32_to_cpu(entry->e_value_inum),
buffer, &size);
buffer, size);
if (error)
goto cleanup;
} else {