Messages in this thread Patch in this message | | | From | Chunhai Guo <> | Subject | [PATCH] erofs: fix to avoid infinite loop in z_erofs_do_read_page() when read page beyond EOF | Date | Mon, 10 Jul 2023 17:34:10 +0800 |
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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> --- 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 d9a0763f4595..b69d89a11dd0 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1035,7 +1035,7 @@ 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; -- 2.25.1
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