From: Ryusuke Konishi konishi.ryusuke@gmail.com

mainline inclusion from mainline-v6.11-rc commit 1ab8425091dba7ce8bf59e09e183aaca6c2a12ac category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGSG3 CVE: CVE-2024-42105

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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Patch series "nilfs2: fix potential issues related to reserved inodes".

This series fixes one use-after-free issue reported by syzbot, caused by nilfs2's internal inode being exposed in the namespace on a corrupted filesystem, and a couple of flaws that cause problems if the starting number of non-reserved inodes written in the on-disk super block is intentionally (or corruptly) changed from its default value.

This patch (of 3):

In the current implementation of nilfs2, "nilfs->ns_first_ino", which gives the first non-reserved inode number, is read from the superblock, but its lower limit is not checked.

As a result, if a number that overlaps with the inode number range of reserved inodes such as the root directory or metadata files is set in the super block parameter, the inode number test macros (NILFS_MDT_INODE and NILFS_VALID_INODE) will not function properly.

In addition, these test macros use left bit-shift calculations using with the inode number as the shift count via the BIT macro, but the result of a shift calculation that exceeds the bit width of an integer is undefined in the C specification, so if "ns_first_ino" is set to a large value other than the default value NILFS_USER_INO (=11), the macros may potentially malfunction depending on the environment.

Fix these issues by checking the lower bound of "nilfs->ns_first_ino" and by preventing bit shifts equal to or greater than the NILFS_USER_INO constant in the inode number test macros.

Also, change the type of "ns_first_ino" from signed integer to unsigned integer to avoid the need for type casting in comparisons such as the lower bound check introduced this time.

Link: https://lkml.kernel.org/r/20240623051135.4180-1-konishi.ryusuke@gmail.com Link: https://lkml.kernel.org/r/20240623051135.4180-2-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: Hillf Danton hdanton@sina.com Cc: Jan Kara jack@suse.cz Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Chen Ridong chenridong@huawei.com --- fs/nilfs2/nilfs.h | 5 +++-- fs/nilfs2/the_nilfs.c | 6 ++++++ fs/nilfs2/the_nilfs.h | 2 +- 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h index a2f247b6a209..cdeefc69ecfc 100644 --- a/fs/nilfs2/nilfs.h +++ b/fs/nilfs2/nilfs.h @@ -121,9 +121,10 @@ enum { #define NILFS_FIRST_INO(sb) (((struct the_nilfs *)sb->s_fs_info)->ns_first_ino)

#define NILFS_MDT_INODE(sb, ino) \ - ((ino) < NILFS_FIRST_INO(sb) && (NILFS_MDT_INO_BITS & BIT(ino))) + ((ino) < NILFS_USER_INO && (NILFS_MDT_INO_BITS & BIT(ino))) #define NILFS_VALID_INODE(sb, ino) \ - ((ino) >= NILFS_FIRST_INO(sb) || (NILFS_SYS_INO_BITS & BIT(ino))) + ((ino) >= NILFS_FIRST_INO(sb) || \ + ((ino) < NILFS_USER_INO && (NILFS_SYS_INO_BITS & BIT(ino))))

/** * struct nilfs_transaction_info: context information for synchronization diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 426d5b065306..dba05e1a8e15 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -403,6 +403,12 @@ static int nilfs_store_disk_layout(struct the_nilfs *nilfs, }

nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino); + if (nilfs->ns_first_ino < NILFS_USER_INO) { + nilfs_err(nilfs->ns_sb, + "too small lower limit for non-reserved inode numbers: %u", + nilfs->ns_first_ino); + return -EINVAL; + }

nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment); if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) { diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 380a543c5b19..dba7e3fe53dd 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -181,7 +181,7 @@ struct the_nilfs { unsigned long ns_nrsvsegs; unsigned long ns_first_data_block; int ns_inode_size; - int ns_first_ino; + unsigned int ns_first_ino; u32 ns_crc_seed;

/* /sys/fs/<nilfs>/<device> */