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ext2: Strengthen xattr block checks 

Check every entry in xattr block for validity in ext2_xattr_set() to
detect on disk corruption early. Also since e_value_block field in xattr
entry is never != 0 in a valid filesystem, just remove checks for it
once we have established entries are valid.

Reviewed-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2019-05-15 15:39:42 +02:00
parent 8cd0f2ba78
commit 6c71b489ec
1 changed files with 10 additions and 12 deletions
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22
fs/ext2/xattr.c
View File

@ -218,6 +218,8 @@ bad_block:
EXT2_XATTR_NEXT(entry);
if ((char *)next >= end)
goto bad_block;
if (!ext2_xattr_entry_valid(entry, inode->i_sb->s_blocksize))
goto bad_block;
if (name_index == entry->e_name_index &&
name_len == entry->e_name_len &&
memcmp(name, entry->e_name, name_len) == 0)
@ -229,9 +231,6 @@ bad_block:
error = -ENODATA;
goto cleanup;
found:
if (!ext2_xattr_entry_valid(entry, inode->i_sb->s_blocksize))
goto bad_block;
size = le32_to_cpu(entry->e_value_size);
if (ext2_xattr_cache_insert(ea_block_cache, bh))
ea_idebug(inode, "cache insert failed");
@ -304,6 +303,8 @@ bad_block:
if ((char *)next >= end)
goto bad_block;
if (!ext2_xattr_entry_valid(entry, inode->i_sb->s_blocksize))
goto bad_block;
entry = next;
}
if (ext2_xattr_cache_insert(ea_block_cache, bh))
@ -446,7 +447,9 @@ bad_block:
struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last);
if ((char *)next >= end)
goto bad_block;
if (!last->e_value_block && last->e_value_size) {
if (!ext2_xattr_entry_valid(last, sb->s_blocksize))
goto bad_block;
if (last->e_value_size) {
size_t offs = le16_to_cpu(last->e_value_offs);
if (offs < min_offs)
min_offs = offs;
@ -489,12 +492,7 @@ bad_block:
error = -EEXIST;
if (flags & XATTR_CREATE)
goto cleanup;
if (!here->e_value_block && here->e_value_size) {
if (!ext2_xattr_entry_valid(here, sb->s_blocksize))
goto bad_block;
free += EXT2_XATTR_SIZE(
le32_to_cpu(here->e_value_size));
}
free += EXT2_XATTR_SIZE(le32_to_cpu(here->e_value_size));
free += EXT2_XATTR_LEN(name_len);
}
error = -ENOSPC;
@ -559,7 +557,7 @@ bad_block:
here->e_name_len = name_len;
memcpy(here->e_name, name, name_len);
} else {
if (!here->e_value_block && here->e_value_size) {
if (here->e_value_size) {
char *first_val = (char *)header + min_offs;
size_t offs = le16_to_cpu(here->e_value_offs);
char *val = (char *)header + offs;
@ -586,7 +584,7 @@ bad_block:
last = ENTRY(header+1);
while (!IS_LAST_ENTRY(last)) {
size_t o = le16_to_cpu(last->e_value_offs);
if (!last->e_value_block && o < offs)
if (o < offs)
last->e_value_offs =
cpu_to_le16(o + size);
last = EXT2_XATTR_NEXT(last);