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ext4: improve xattr consistency checking and error reporting 

Refactor the in-inode and xattr block consistency checking, and report
more fine-grained reports of the consistency problems.  Also add more
consistency checks for ea_inode number.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20221214200818.870087-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2022-12-14 15:08:18 -05:00
parent 2241ab53cb
commit 3478c83cf2
1 changed files with 80 additions and 46 deletions
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126
fs/ext4/xattr.c
View File

@ -184,27 +184,73 @@ ext4_xattr_handler(int name_index)
}
static int
ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
void *value_start)
check_xattrs(struct inode *inode, struct buffer_head *bh,
struct ext4_xattr_entry *entry, void *end, void *value_start,
const char *function, unsigned int line)
{
struct ext4_xattr_entry *e = entry;
int err = -EFSCORRUPTED;
char *err_str;
if (bh) {
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1)) {
err_str = "invalid header";
goto errout;
}
if (buffer_verified(bh))
return 0;
if (!ext4_xattr_block_csum_verify(inode, bh)) {
err = -EFSBADCRC;
err_str = "invalid checksum";
goto errout;
}
} else {
struct ext4_xattr_ibody_header *header = value_start;
header -= 1;
if (end - (void *)header < sizeof(*header) + sizeof(u32)) {
err_str = "in-inode xattr block too small";
goto errout;
}
if (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
err_str = "bad magic number in in-inode xattr";
goto errout;
}
}
/* Find the end of the names list */
while (!IS_LAST_ENTRY(e)) {
struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
if ((void *)next >= end)
return -EFSCORRUPTED;
if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
return -EFSCORRUPTED;
if ((void *)next >= end) {
err_str = "e_name out of bounds";
goto errout;
}
if (strnlen(e->e_name, e->e_name_len) != e->e_name_len) {
err_str = "bad e_name length";
goto errout;
}
e = next;
}
/* Check the values */
while (!IS_LAST_ENTRY(entry)) {
u32 size = le32_to_cpu(entry->e_value_size);
unsigned long ea_ino = le32_to_cpu(entry->e_value_inum);
if (size > EXT4_XATTR_SIZE_MAX)
return -EFSCORRUPTED;
if (!ext4_has_feature_ea_inode(inode->i_sb) && ea_ino) {
err_str = "ea_inode specified without ea_inode feature enabled";
goto errout;
}
if (ea_ino && ((ea_ino == EXT4_ROOT_INO) ||
!ext4_valid_inum(inode->i_sb, ea_ino))) {
err_str = "invalid ea_ino";
goto errout;
}
if (size > EXT4_XATTR_SIZE_MAX) {
err_str = "e_value size too large";
goto errout;
}
if (size != 0 && entry->e_value_inum == 0) {
u16 offs = le16_to_cpu(entry->e_value_offs);
@ -216,66 +262,54 @@ ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
* the padded and unpadded sizes, since the size may
* overflow to 0 when adding padding.
*/
if (offs > end - value_start)
return -EFSCORRUPTED;
if (offs > end - value_start) {
err_str = "e_value out of bounds";
goto errout;
}
value = value_start + offs;
if (value < (void *)e + sizeof(u32) ||
size > end - value ||
EXT4_XATTR_SIZE(size) > end - value)
return -EFSCORRUPTED;
EXT4_XATTR_SIZE(size) > end - value) {
err_str = "overlapping e_value ";
goto errout;
}
}
entry = EXT4_XATTR_NEXT(entry);
}
if (bh)
set_buffer_verified(bh);
return 0;
errout:
if (bh)
__ext4_error_inode(inode, function, line, 0, -err,
"corrupted xattr block %llu: %s",
(unsigned long long) bh->b_blocknr,
err_str);
else
__ext4_error_inode(inode, function, line, 0, -err,
"corrupted in-inode xattr: %s", err_str);
return err;
}
static inline int
__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
const char *function, unsigned int line)
{
int error = -EFSCORRUPTED;
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1))
goto errout;
if (buffer_verified(bh))
return 0;
error = -EFSBADCRC;
if (!ext4_xattr_block_csum_verify(inode, bh))
goto errout;
error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
bh->b_data);
errout:
if (error)
__ext4_error_inode(inode, function, line, 0, -error,
"corrupted xattr block %llu",
(unsigned long long) bh->b_blocknr);
else
set_buffer_verified(bh);
return error;
return check_xattrs(inode, bh, BFIRST(bh), bh->b_data + bh->b_size,
bh->b_data, function, line);
}
#define ext4_xattr_check_block(inode, bh) \
__ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
static int
static inline int
__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
void *end, const char *function, unsigned int line)
{
int error = -EFSCORRUPTED;
if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
(header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
goto errout;
error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
errout:
if (error)
__ext4_error_inode(inode, function, line, 0, -error,
"corrupted in-inode xattr");
return error;
return check_xattrs(inode, NULL, IFIRST(header), end, IFIRST(header),
function, line);
}
#define xattr_check_inode(inode, header, end) \