@@ -276,18 +276,22 @@ __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
__xattr_check_inode((inode), (header), (end), __func__, __LINE__)
static int
-ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
- const char *name, int sorted)
+xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
+ void *end, int name_index, const char *name, int sorted)
{
- struct ext4_xattr_entry *entry;
+ struct ext4_xattr_entry *entry, *next;
size_t name_len;
int cmp = 1;
if (name == NULL)
return -EINVAL;
name_len = strlen(name);
- entry = *pentry;
- for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
+ for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
+ next = EXT4_XATTR_NEXT(entry);
+ if ((void *) next >= end) {
+ EXT4_ERROR_INODE(inode, "corrupted xattr entries");
+ return -EFSCORRUPTED;
+ }
cmp = name_index - entry->e_name_index;
if (!cmp)
cmp = name_len - entry->e_name_len;
@@ -509,6 +513,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
struct buffer_head *bh = NULL;
struct ext4_xattr_entry *entry;
size_t size;
+ void *end;
int error;
struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
@@ -530,7 +535,8 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
goto cleanup;
ext4_xattr_block_cache_insert(ea_block_cache, bh);
entry = BFIRST(bh);
- error = ext4_xattr_find_entry(&entry, name_index, name, 1);
+ end = bh->b_data + bh->b_size;
+ error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
if (error)
goto cleanup;
size = le32_to_cpu(entry->e_value_size);
@@ -579,7 +585,7 @@ ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
if (error)
goto cleanup;
entry = IFIRST(header);
- error = ext4_xattr_find_entry(&entry, name_index, name, 0);
+ error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
if (error)
goto cleanup;
size = le32_to_cpu(entry->e_value_size);
@@ -1808,8 +1814,8 @@ ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
bs->s.first = BFIRST(bs->bh);
bs->s.end = bs->bh->b_data + bs->bh->b_size;
bs->s.here = bs->s.first;
- error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
- i->name, 1);
+ error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
+ i->name_index, i->name, 1);
if (error && error != -ENODATA)
goto cleanup;
bs->s.not_found = error;
@@ -2168,8 +2174,8 @@ int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
if (error)
return error;
/* Find the named attribute. */
- error = ext4_xattr_find_entry(&is->s.here, i->name_index,
- i->name, 0);
+ error = xattr_find_entry(inode, &is->s.here, is->s.end,
+ i->name_index, i->name, 0);
if (error && error != -ENODATA)
return error;
is->s.not_found = error;
Add some paranoia checks to make sure we don't stray beyond the end of the valid memory region containing ext4 xattr entries while we are scanning for a match. Also rename the function to xattr_find_entry() since it is static and thus only used in fs/ext4/xattr.c Signed-off-by: Theodore Ts'o <tytso@mit.edu> --- fs/ext4/xattr.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-)