[PATCH AUTOSEL 5.7 34/61] f2fs: remove write attribute of main_blkaddr sysfs node
From: Sasha Levin <sashal@kernel.org>
Date: 2020-08-21 17:19:32
Also in:
linux-f2fs-devel, lkml
Subsystem:
f2fs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Jaegeuk Kim, Chao Yu, Alexander Viro, Christian Brauner, Linus Torvalds
From: Dehe Gu <redacted> [ Upstream commit ffcde4b29a5f20ddca6fe559b48f345818bf1d91 ] Fuzzing main_blkaddr sysfs node will corrupt this field's value, causing kernel panic, remove its write attribute to avoid potential security risk. [Chao Yu: add description] Signed-off-by: Dehe Gu <redacted> Signed-off-by: Daiyue Zhang <redacted> Reviewed-by: Chao Yu <redacted> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/f2fs/sysfs.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index e3bbbef9b4f09..66e8b243e48eb 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c@@ -222,6 +222,13 @@ static ssize_t avg_vblocks_show(struct f2fs_attr *a, } #endif +static ssize_t main_blkaddr_show(struct f2fs_attr *a, + struct f2fs_sb_info *sbi, char *buf) +{ + return snprintf(buf, PAGE_SIZE, "%llu\n", + (unsigned long long)MAIN_BLKADDR(sbi)); +} + static ssize_t f2fs_sbi_show(struct f2fs_attr *a, struct f2fs_sb_info *sbi, char *buf) {
@@ -511,7 +518,6 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time); F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_idle, gc_mode); F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_urgent, gc_mode); F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments); -F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, main_blkaddr, main_blkaddr); F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_small_discards, max_discards); F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity); F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
@@ -551,6 +557,7 @@ F2FS_GENERAL_RO_ATTR(current_reserved_blocks); F2FS_GENERAL_RO_ATTR(unusable); F2FS_GENERAL_RO_ATTR(encoding); F2FS_GENERAL_RO_ATTR(mounted_time_sec); +F2FS_GENERAL_RO_ATTR(main_blkaddr); #ifdef CONFIG_F2FS_STAT_FS F2FS_STAT_ATTR(STAT_INFO, f2fs_stat_info, cp_foreground_calls, cp_count); F2FS_STAT_ATTR(STAT_INFO, f2fs_stat_info, cp_background_calls, bg_cp_count);
--
2.25.1