Since some crafted EROFS filesystem images could have insane large extents, which causes unexpected bahaviors when extracting data.
Fix it by extracting large extents with a buffer with a reasonable maximum size limit and reading multiple times instead. Note that only `--extract` option is impacted. CVE: CVE-2023-33552 Closes: https://nvd.nist.gov/vuln/detail/CVE-2023-33552 Reported-by: Chaoming Yang <[email protected]> Fixes: 412c8f908132 ("erofs-utils: fsck: add --extract=X support to extract to path X") Signed-off-by: Gao Xiang <[email protected]> --- fsck/main.c | 62 ++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 15 deletions(-) diff --git a/fsck/main.c b/fsck/main.c index ad40537..6f89a1e 100644 --- a/fsck/main.c +++ b/fsck/main.c @@ -392,6 +392,8 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd) } while (pos < inode->i_size) { + int alloc_rawsize; + map.m_la = pos; if (compressed) ret = z_erofs_map_blocks_iter(inode, &map, @@ -420,10 +422,27 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd) if (!(map.m_flags & EROFS_MAP_MAPPED) || !fsckcfg.check_decomp) continue; - if (map.m_plen > raw_size) { - raw_size = map.m_plen; - raw = realloc(raw, raw_size); - BUG_ON(!raw); + if (map.m_plen > Z_EROFS_PCLUSTER_MAX_SIZE) { + if (compressed) { + erofs_err("invalid pcluster size %" PRIu64 " @ offset %" PRIu64 " of nid %" PRIu64, + map.m_plen, map.m_la, inode->nid); + ret = -EFSCORRUPTED; + goto out; + } + alloc_rawsize = Z_EROFS_PCLUSTER_MAX_SIZE; + } else { + alloc_rawsize = map.m_plen; + } + + if (alloc_rawsize > raw_size) { + char *newraw = realloc(raw, alloc_rawsize); + + if (!newraw) { + ret = -ENOMEM; + goto out; + } + raw = newraw; + raw_size = alloc_rawsize; } if (compressed) { @@ -434,18 +453,25 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd) } ret = z_erofs_read_one_data(inode, &map, raw, buffer, 0, map.m_llen, false); - } else { - ret = erofs_read_one_data(&map, raw, 0, map.m_plen); - } - if (ret) - goto out; + if (ret) + goto out; - if (outfd >= 0 && write(outfd, compressed ? buffer : raw, - map.m_llen) < 0) { - erofs_err("I/O error occurred when verifying data chunk @ nid %llu", - inode->nid | 0ULL); - ret = -EIO; - goto out; + if (outfd >= 0 && write(outfd, buffer, map.m_llen) < 0) + goto fail_eio; + } else { + u64 count, p = 0; + + do { + count = min_t(u64, alloc_rawsize, map.m_llen); + ret = erofs_read_one_data(&map, raw, p, count); + if (ret) + goto out; + + if (outfd >= 0 && write(outfd, raw, count) < 0) + goto fail_eio; + map.m_llen -= count; + p += count; + } while (map.m_llen); } } @@ -460,6 +486,12 @@ out: if (buffer) free(buffer); return ret < 0 ? ret : 0; + +fail_eio: + erofs_err("I/O error occurred when verifying data chunk @ nid %llu", + inode->nid | 0ULL); + ret = -EIO; + goto out; } static inline int erofs_extract_dir(struct erofs_inode *inode) -- 2.24.4
