The quilt patch titled Subject: nilfs2: fix shift-out-of-bounds due to too large exponent of block size has been removed from the -mm tree. Its filename was nilfs2-fix-shift-out-of-bounds-due-to-too-large-exponent-of-block-size.patch This patch was dropped because it was merged into the mm-nonmm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Subject: nilfs2: fix shift-out-of-bounds due to too large exponent of block size Date: Thu, 27 Oct 2022 13:43:06 +0900 If field s_log_block_size of superblock data is corrupted and too large, init_nilfs() and load_nilfs() still can trigger a shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn is set): shift exponent 38973 is too large for 32-bit type 'int' Call Trace: <TASK> dump_stack_lvl+0xcd/0x134 ubsan_epilogue+0xb/0x50 __ubsan_handle_shift_out_of_bounds.cold.12+0x17b/0x1f5 init_nilfs.cold.11+0x18/0x1d [nilfs2] nilfs_mount+0x9b5/0x12b0 [nilfs2] ... This fixes the issue by adding and using a new helper function for getting block size with sanity check. Link: https://lkml.kernel.org/r/20221027044306.42774-3-konishi.ryusuke@xxxxxxxxx Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/nilfs2/the_nilfs.c | 42 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) --- a/fs/nilfs2/the_nilfs.c~nilfs2-fix-shift-out-of-bounds-due-to-too-large-exponent-of-block-size +++ a/fs/nilfs2/the_nilfs.c @@ -194,6 +194,34 @@ static int nilfs_store_log_cursor(struct } /** + * nilfs_get_blocksize - get block size from raw superblock data + * @sb: super block instance + * @sbp: superblock raw data buffer + * @blocksize: place to store block size + * + * nilfs_get_blocksize() calculates the block size from the block size + * exponent information written in @sbp and stores it in @blocksize, + * or aborts with an error message if it's too large. + * + * Return Value: On success, 0 is returned. If the block size is too + * large, -EINVAL is returned. + */ +static int nilfs_get_blocksize(struct super_block *sb, + struct nilfs_super_block *sbp, int *blocksize) +{ + unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size); + + if (unlikely(shift_bits > + ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) { + nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB", + shift_bits); + return -EINVAL; + } + *blocksize = BLOCK_SIZE << shift_bits; + return 0; +} + +/** * load_nilfs - load and recover the nilfs * @nilfs: the_nilfs structure to be released * @sb: super block instance used to recover past segment @@ -246,11 +274,15 @@ int load_nilfs(struct the_nilfs *nilfs, nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime); /* verify consistency between two super blocks */ - blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size); + err = nilfs_get_blocksize(sb, sbp[0], &blocksize); + if (err) + goto scan_error; + if (blocksize != nilfs->ns_blocksize) { nilfs_warn(sb, "blocksize differs between two super blocks (%d != %d)", blocksize, nilfs->ns_blocksize); + err = -EINVAL; goto scan_error; } @@ -609,9 +641,11 @@ int init_nilfs(struct the_nilfs *nilfs, if (err) goto failed_sbh; - blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size); - if (blocksize < NILFS_MIN_BLOCK_SIZE || - blocksize > NILFS_MAX_BLOCK_SIZE) { + err = nilfs_get_blocksize(sb, sbp, &blocksize); + if (err) + goto failed_sbh; + + if (blocksize < NILFS_MIN_BLOCK_SIZE) { nilfs_err(sb, "couldn't mount because of unsupported filesystem blocksize %d", blocksize); _ Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxx are