From: Baokun Li <libaokun1@huawei.com> mainline inclusion from mainline-v6.12-rc1 commit edfa71dbe841075109e3e1da7d3925b45328ed25 category: other bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14192 CVE: CVE-2026-31449 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- As suggested by Honza in Link，modify ext4_ext_rm_idx() to leave 'path' alone and just index it like ext4_ext_correct_indexes() does it. This facilitates adding error handling later. No functional changes. Suggested-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/all/20230216130305.nrbtd42tppxhbynn@quack3/ Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-2-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/ext4/extents.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 4c77284be84d..045c27956dda 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2285,48 +2285,46 @@ static ext4_lblk_t ext4_ext_find_hole(struct inode *inode, static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, int depth) { int err; ext4_fsblk_t leaf; + int k = depth - 1; /* free index block */ - depth--; - path = path + depth; - leaf = ext4_idx_pblock(path->p_idx); - if (unlikely(path->p_hdr->eh_entries == 0)) { - EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0"); + leaf = ext4_idx_pblock(path[k].p_idx); + if (unlikely(path[k].p_hdr->eh_entries == 0)) { + EXT4_ERROR_INODE(inode, "path[%d].p_hdr->eh_entries == 0", k); return -EFSCORRUPTED; } - err = ext4_ext_get_access(handle, inode, path); + err = ext4_ext_get_access(handle, inode, path + k); if (err) return err; - if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) { - int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx; + if (path[k].p_idx != EXT_LAST_INDEX(path[k].p_hdr)) { + int len = EXT_LAST_INDEX(path[k].p_hdr) - path[k].p_idx; len *= sizeof(struct ext4_extent_idx); - memmove(path->p_idx, path->p_idx + 1, len); + memmove(path[k].p_idx, path[k].p_idx + 1, len); } - le16_add_cpu(&path->p_hdr->eh_entries, -1); - err = ext4_ext_dirty(handle, inode, path); + le16_add_cpu(&path[k].p_hdr->eh_entries, -1); + err = ext4_ext_dirty(handle, inode, path + k); if (err) return err; ext_debug(inode, "index is empty, remove it, free block %llu\n", leaf); trace_ext4_ext_rm_idx(inode, leaf); ext4_free_blocks(handle, inode, NULL, leaf, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); - while (--depth >= 0) { - if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr)) + while (--k >= 0) { + if (path[k + 1].p_idx != EXT_FIRST_INDEX(path[k + 1].p_hdr)) break; - path--; - err = ext4_ext_get_access(handle, inode, path); + err = ext4_ext_get_access(handle, inode, path + k); if (err) break; - path->p_idx->ei_block = (path+1)->p_idx->ei_block; - err = ext4_ext_dirty(handle, inode, path); + path[k].p_idx->ei_block = path[k + 1].p_idx->ei_block; + err = ext4_ext_dirty(handle, inode, path + k); if (err) break; } return err; } -- 2.52.0