3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o tytso@mit.edu
commit 9e92f48c34eb2b9af9d12f892e2fe1fce5e8ce35 upstream.
We aren't checking to see if the in-inode extended attribute is corrupted before we try to expand the inode's extra isize fields.
This can lead to potential crashes caused by the BUG_ON() check in ext4_xattr_shift_entries().
Signed-off-by: Theodore Ts'o tytso@mit.edu [bwh: Backported to 3.16: s/EFSCORRUPTED/EIO/] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/ext4/xattr.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-)
--- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -243,6 +243,27 @@ ext4_xattr_check_block(struct inode *ino return error; }
+static int +__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header, + void *end, const char *function, unsigned int line) +{ + struct ext4_xattr_entry *entry = IFIRST(header); + int error = -EIO; + + if (((void *) header >= end) || + (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC))) + goto errout; + error = ext4_xattr_check_names(entry, end, entry); +errout: + if (error) + __ext4_error_inode(inode, function, line, 0, + "corrupted in-inode xattr"); + return error; +} + +#define xattr_check_inode(inode, header, end) \ + __xattr_check_inode((inode), (header), (end), __func__, __LINE__) + static inline int ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) { @@ -368,7 +389,7 @@ ext4_xattr_ibody_get(struct inode *inode header = IHDR(inode, raw_inode); entry = IFIRST(header); end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; - error = ext4_xattr_check_names(entry, end, entry); + error = xattr_check_inode(inode, header, end); if (error) goto cleanup; error = xattr_find_entry(inode, &entry, end, name_index, name, @@ -506,7 +527,7 @@ ext4_xattr_ibody_list(struct dentry *den raw_inode = ext4_raw_inode(&iloc); header = IHDR(inode, raw_inode); end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; - error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header)); + error = xattr_check_inode(inode, header, end); if (error) goto cleanup; error = ext4_xattr_list_entries(dentry, IFIRST(header), @@ -1038,8 +1059,7 @@ int ext4_xattr_ibody_find(struct inode * is->s.here = is->s.first; is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { - error = ext4_xattr_check_names(IFIRST(header), is->s.end, - IFIRST(header)); + error = xattr_check_inode(inode, header, is->s.end); if (error) return error; /* Find the named attribute. */ @@ -1319,6 +1339,10 @@ retry: last = entry; total_ino = sizeof(struct ext4_xattr_ibody_header);
+ error = xattr_check_inode(inode, header, end); + if (error) + goto cleanup; + free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); if (free >= new_extra_isize) { entry = IFIRST(header);