From: Chunhai Guo guochunhai@vivo.com
[ Upstream commit 8191213a5835b0317c5e4d0d337ae1ae00c75253 ]
z_erofs_do_read_page() may loop infinitely due to the inappropriate truncation in the below statement. Since the offset is 64 bits and min_t() truncates the result to 32 bits. The solution is to replace unsigned int with a 64-bit type, such as erofs_off_t. cur = end - min_t(unsigned int, offset + end - map->m_la, end);
- For example: - offset = 0x400160000 - end = 0x370 - map->m_la = 0x160370 - offset + end - map->m_la = 0x400000000 - offset + end - map->m_la = 0x00000000 (truncated as unsigned int) - Expected result: - cur = 0 - Actual result: - cur = 0x370
Signed-off-by: Chunhai Guo guochunhai@vivo.com Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Reviewed-by: Gao Xiang hsiangkao@linux.alibaba.com Reviewed-by: Chao Yu chao@kernel.org Link: https://lore.kernel.org/r/20230710093410.44071-1-guochunhai@vivo.com Signed-off-by: Gao Xiang hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/erofs/zdata.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index bedfff5d45faf..997ca4b32e87f 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -990,7 +990,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, */ tight &= (fe->mode > Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE);
- cur = end - min_t(unsigned int, offset + end - map->m_la, end); + cur = end - min_t(erofs_off_t, offset + end - map->m_la, end); if (!(map->m_flags & EROFS_MAP_MAPPED)) { zero_user_segment(page, cur, end); goto next_part;