From 8c7e720a165baeaff3853d1cfe017f596381ae1d Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 11 Aug 2020 18:35:27 -0700 Subject: fs/minix: don't allow getting deleted inodes commit facb03dddec04e4aac1bb2139accdceb04deb1f3 upstream. If an inode has no links, we need to mark it bad rather than allowing it to be accessed. This avoids WARNINGs in inc_nlink() and drop_nlink() when doing directory operations on a fuzzed filesystem. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+a9ac3de1b5de5fb10efc@syzkaller.appspotmail.com Reported-by: syzbot+df958cf5688a96ad3287@syzkaller.appspotmail.com Signed-off-by: Eric Biggers Signed-off-by: Andrew Morton Cc: Alexander Viro Cc: Qiujun Huang Cc: Link: http://lkml.kernel.org/r/20200628060846.682158-3-ebiggers@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/minix/inode.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'fs/minix/inode.c') diff --git a/fs/minix/inode.c b/fs/minix/inode.c index 7cb5fd38eb14..2bca95abe8f4 100644 --- a/fs/minix/inode.c +++ b/fs/minix/inode.c @@ -468,6 +468,13 @@ static struct inode *V1_minix_iget(struct inode *inode) iget_failed(inode); return ERR_PTR(-EIO); } + if (raw_inode->i_nlinks == 0) { + printk("MINIX-fs: deleted inode referenced: %lu\n", + inode->i_ino); + brelse(bh); + iget_failed(inode); + return ERR_PTR(-ESTALE); + } inode->i_mode = raw_inode->i_mode; i_uid_write(inode, raw_inode->i_uid); i_gid_write(inode, raw_inode->i_gid); @@ -501,6 +508,13 @@ static struct inode *V2_minix_iget(struct inode *inode) iget_failed(inode); return ERR_PTR(-EIO); } + if (raw_inode->i_nlinks == 0) { + printk("MINIX-fs: deleted inode referenced: %lu\n", + inode->i_ino); + brelse(bh); + iget_failed(inode); + return ERR_PTR(-ESTALE); + } inode->i_mode = raw_inode->i_mode; i_uid_write(inode, raw_inode->i_uid); i_gid_write(inode, raw_inode->i_gid); -- cgit v1.2.3 From db1f4c745a91c3988c57cefb125c7a01711de5e2 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 11 Aug 2020 18:35:30 -0700 Subject: fs/minix: reject too-large maximum file size commit 270ef41094e9fa95273f288d7d785313ceab2ff3 upstream. If the minix filesystem tries to map a very large logical block number to its on-disk location, block_to_path() can return offsets that are too large, causing out-of-bounds memory accesses when accessing indirect index blocks. This should be prevented by the check against the maximum file size, but this doesn't work because the maximum file size is read directly from the on-disk superblock and isn't validated itself. Fix this by validating the maximum file size at mount time. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+c7d9ec7a1a7272dd71b3@syzkaller.appspotmail.com Reported-by: syzbot+3b7b03a0c28948054fb5@syzkaller.appspotmail.com Reported-by: syzbot+6e056ee473568865f3e6@syzkaller.appspotmail.com Signed-off-by: Eric Biggers Signed-off-by: Andrew Morton Cc: Alexander Viro Cc: Qiujun Huang Cc: Link: http://lkml.kernel.org/r/20200628060846.682158-4-ebiggers@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/minix/inode.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) (limited to 'fs/minix/inode.c') diff --git a/fs/minix/inode.c b/fs/minix/inode.c index 2bca95abe8f4..0dd929346f3f 100644 --- a/fs/minix/inode.c +++ b/fs/minix/inode.c @@ -150,6 +150,23 @@ static int minix_remount (struct super_block * sb, int * flags, char * data) return 0; } +static bool minix_check_superblock(struct minix_sb_info *sbi) +{ + if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0) + return false; + + /* + * s_max_size must not exceed the block mapping limitation. This check + * is only needed for V1 filesystems, since V2/V3 support an extra level + * of indirect blocks which places the limit well above U32_MAX. + */ + if (sbi->s_version == MINIX_V1 && + sbi->s_max_size > (7 + 512 + 512*512) * BLOCK_SIZE) + return false; + + return true; +} + static int minix_fill_super(struct super_block *s, void *data, int silent) { struct buffer_head *bh; @@ -228,11 +245,12 @@ static int minix_fill_super(struct super_block *s, void *data, int silent) } else goto out_no_fs; + if (!minix_check_superblock(sbi)) + goto out_illegal_sb; + /* * Allocate the buffer map to keep the superblock small. */ - if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0) - goto out_illegal_sb; i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh); map = kzalloc(i, GFP_KERNEL); if (!map) -- cgit v1.2.3 From 6def476496a551ef02f25b2c8c7d817e97d72a87 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 11 Aug 2020 18:35:33 -0700 Subject: fs/minix: set s_maxbytes correctly [ Upstream commit 32ac86efff91a3e4ef8c3d1cadd4559e23c8e73a ] The minix filesystem leaves super_block::s_maxbytes at MAX_NON_LFS rather than setting it to the actual filesystem-specific limit. This is broken because it means userspace doesn't see the standard behavior like getting EFBIG and SIGXFSZ when exceeding the maximum file size. Fix this by setting s_maxbytes correctly. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Biggers Signed-off-by: Andrew Morton Cc: Alexander Viro Cc: Qiujun Huang Link: http://lkml.kernel.org/r/20200628060846.682158-5-ebiggers@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/minix/inode.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'fs/minix/inode.c') diff --git a/fs/minix/inode.c b/fs/minix/inode.c index 0dd929346f3f..7b09a9158e40 100644 --- a/fs/minix/inode.c +++ b/fs/minix/inode.c @@ -150,8 +150,10 @@ static int minix_remount (struct super_block * sb, int * flags, char * data) return 0; } -static bool minix_check_superblock(struct minix_sb_info *sbi) +static bool minix_check_superblock(struct super_block *sb) { + struct minix_sb_info *sbi = minix_sb(sb); + if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0) return false; @@ -161,7 +163,7 @@ static bool minix_check_superblock(struct minix_sb_info *sbi) * of indirect blocks which places the limit well above U32_MAX. */ if (sbi->s_version == MINIX_V1 && - sbi->s_max_size > (7 + 512 + 512*512) * BLOCK_SIZE) + sb->s_maxbytes > (7 + 512 + 512*512) * BLOCK_SIZE) return false; return true; @@ -202,7 +204,7 @@ static int minix_fill_super(struct super_block *s, void *data, int silent) sbi->s_zmap_blocks = ms->s_zmap_blocks; sbi->s_firstdatazone = ms->s_firstdatazone; sbi->s_log_zone_size = ms->s_log_zone_size; - sbi->s_max_size = ms->s_max_size; + s->s_maxbytes = ms->s_max_size; s->s_magic = ms->s_magic; if (s->s_magic == MINIX_SUPER_MAGIC) { sbi->s_version = MINIX_V1; @@ -233,7 +235,7 @@ static int minix_fill_super(struct super_block *s, void *data, int silent) sbi->s_zmap_blocks = m3s->s_zmap_blocks; sbi->s_firstdatazone = m3s->s_firstdatazone; sbi->s_log_zone_size = m3s->s_log_zone_size; - sbi->s_max_size = m3s->s_max_size; + s->s_maxbytes = m3s->s_max_size; sbi->s_ninodes = m3s->s_ninodes; sbi->s_nzones = m3s->s_zones; sbi->s_dirsize = 64; @@ -245,7 +247,7 @@ static int minix_fill_super(struct super_block *s, void *data, int silent) } else goto out_no_fs; - if (!minix_check_superblock(sbi)) + if (!minix_check_superblock(s)) goto out_illegal_sb; /* -- cgit v1.2.3